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    Impact of bistrand abasic sites and proximate orientation on DNA global structure and duplex energetics.
    Biopolymers 2018 Jan 11. Epub 2018 Jan 11.
    Department of Chemistry and Chemical Biology, Rutgers - The State University of New Jersey, Piscataway, New Jersey.
    Bistrand lesions embedded within a single helical turn of tridecameric deoxyoligonucleotide duplexes represent a model system for exploring the impact of clustered lesions that occur in vivo and pose a significant challenge to cellular repair machineries. Such investigations are essential for understanding the forces that dictate lesion-induced mutagenesis, carcinogenesis, and cytotoxicity within a context that mimics local helical perturbations caused by an ionizing radiation event. This study characterizes the structural and energy profiles of DNA duplexes harboring synthetic abasic sites (tetrahydrofuran, F) as models of clustered bistrand abasic (AP) lesions. Read More

    A long-lived Aβ oligomer resistant to fibrillization.
    Biopolymers 2018 Jan 10. Epub 2018 Jan 10.
    Department of Pharmaceutical Chemistry, University of California, San Francisco, California.
    The hydrophobic Aβ peptide is highly aggregation prone; it first forms soluble oligomers, which then convert into the amyloid fibrils found in the cerebral plaques of Alzheimer's disease. It is generally understood that as the peptide concentration of Aβ increases, the fibrillization process is accelerated, but we examine the limits on this phenomenon. We found that once a threshold concentration of Aβ is exceeded, a stable oligomer is formed at the expense of fibril formation. Read More

    An entirely fmoc solid phase approach to the synthesis of daptomycin analogs.
    Biopolymers 2018 Jan 2. Epub 2018 Jan 2.
    Department of Chemistry, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, N2L 3G1, Canada.
    Daptomycin is an important Ca2+ -dependent cyclic lipodepsipeptide antibiotic used to treat serious gram-positive infections. The search for daptomycin analogs with improved activity and their application as tools for studying its mechanism of action has prompted us to develop an entirely Fmoc solid phase approach to the synthesis of daptomycin analogs. Key to the success of this approach was the development of conditions that allowed for the formation of the ester bond on resin-bound peptides consisting of residues 1-10 and the decanoyl lipid tail. Read More

    Balancing hydrophobicity and sequence pattern to influence self-assembly of amphipathic peptides.
    Biopolymers 2018 Jan 2. Epub 2018 Jan 2.
    Department of Chemistry, University of Rochester, Rochester, New York.
    Amphipathic peptides with alternating polar and nonpolar amino acid sequences efficiently self-assemble into functional β-sheet fibrils as long as the nonpolar residues have sufficient hydrophobicity. For example, the Ac-(FKFE)2 -NH2 peptide rapidly self-assembles into β-sheet bilayer nanoribbons, while Ac-(AKAE)2 -NH2 fails to self-assemble under similar conditions due to the significantly reduced hydrophobicity and β-sheet propensity of Ala relative to Phe. Herein, we systematically explore the effect of substituting only two of the four Ala residues at various positions in the Ac-(AKAE)2 -NH2 peptide with amino acids of increasing hydrophobicity, β-sheet potential, and surface area (including Phe, 1-naphthylalanine (1-Nal), 2-naphthylalanine (2-Nal), cyclohexylalanine (Cha), and pentafluorophenylalanine (F5 -Phe)) on the self-assembly propensity of the resulting sequences. Read More

    Marine antimicrobial peptide arenicin adopts a monomeric twisted β-hairpin structure and forms low conductivity pores in zwitterionic lipid bilayers.
    Biopolymers 2017 Dec 21. Epub 2017 Dec 21.
    M.M. Shemyakin and Yu. A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya str., 16/10, Moscow, 117997, Russia.
    Arenicins are 21-residue β-hairpin antimicrobial peptides (AMPs) isolated from the marine lugworm Arenicola marina [Ovchinnikova et al., FEBS Lett. 2004;577:209-214]. Read More

    Peptibodies: An elegant solution for a long-standing problem.
    Biopolymers 2017 Dec 21. Epub 2017 Dec 21.
    Faculdade de Medicina, Instituto de Medicina Molecular, Universidade de Lisboa, Av. Prof. Egas Moniz, Lisboa, 1649-028, Portugal.
    Chimeric proteins composed of a biologically active peptide and a fragment crystallizable (Fc) domain of immunoglobulin G (IgG) are known as peptibodies. They present an extended half-life due to neonatal Fc receptor (FcRn) salvage pathway, a decreased renal clearance rate owing to its increased size (≈70 kDa) and, depending on the peptide used in the design of the peptibody, an active-targeting moiety. Also, the peptides therapeutic activity is boosted by the number of peptides in the fusion protein (at least two peptides) and to some peptides' alterations. Read More

    Jack Aviv and brains of children.
    Biopolymers 2017 Dec 4. Epub 2017 Dec 4.
    Department of Pediatrics, Division of Neonatal and Developmental Medicine, Stanford University School of Medicine, Stanford, California.
    Both lead intoxication in early childhood and deficient bilirubin-binding capacity (BBC) of blood in jaundiced neonates indicate risk for brain damage. Zinc protoporphyrin (ZPP) is a biomarker for lead intoxication (PbI) as well as well as for iron deficiency. Under the leadership of Jack Aviv, Aviv Biomedical, Inc. Read More

    Amphiphilic lysine conjugated to tobramycin synergizes legacy antibiotics against wild-type and multidrug-resistant Pseudomonas aeruginosa.
    Biopolymers 2017 Dec 4. Epub 2017 Dec 4.
    Department of Chemistry, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada.
    Peptidomimetic modification is a common route of optimization for biologically active peptides. Previous studies in our group have shown that conjugation of amphiphilic tobramycin to other antibacterials enhance their latent outer membrane permeabilizing and efflux blocking activity toward Gram-negative pathogens including Pseudomonas aeruginosa. Herein, we describe the antimicrobial adjuvant properties of amphiphilic lysine ligated to tobramycin. Read More

    Enzymatic degradation of hyaluronan hydrogels with different capacity for in situ bio-mineralization.
    Biopolymers 2017 Nov 27. Epub 2017 Nov 27.
    Science for Life Laboratory, Division of Polymer Chemistry, Department of Chemistry-Ångström, Uppsala University, Uppsala, Sweden.
    In situ cross-linked hyaluronan (HA) hydrogels with different capacities for biomineralization were prepared and their enzymatic degradation was monitored. Covalent incorporation of bisphosphonates (BPs) into HA hydrogel results in the increased stiffness of the hydrogel in comparison with the unmodified HA hydrogel of the same cross-linking density. The rate of enzymatic degradation of HABP hydrogel was significantly lower than the rate of degradation of control HA hydrogel in vitro. Read More

    Selective detection of α4β1 integrin (VLA-4)-expressing cells using peptide-functionalized nanostructured materials mimicking endothelial surfaces adjacent to inflammatory sites.
    Biopolymers 2017 Nov 27. Epub 2017 Nov 27.
    Department of Chemistry "G. Ciamician", University of Bologna, via Selmi 2, Bologna, 40126, Italy.
    Persistent accumulation of immune cells mediated by α4β1 integrin (VLA-4) is a hallmark of the inflammatory diseases and of chronic inflammation observed in the affected tissues of autoimmune diseases. Aiming at exploring new methods for monitoring the course of the inflammatory processes, we designed the first peptide-functionalized nanostructured devices capable to mimic the high-density multivalency binding between the α4β1 integrin-expressing cells and the ligands overexpressed on the endothelial surfaces, in the proximity of the sites of inflammation. Specifically, we describe the first examples of monolayers constituted by dye-loaded zeolite L crystals, coated with α4β1 integrin peptide ligands, and we analyze the adhesion of model Jurkat cells in comparison to non-α4β1 integrin-expressing cells. Read More

    Crystallographic insights into the self-assembly of KLVFF amyloid-beta peptides.
    Biopolymers 2017 Nov 27. Epub 2017 Nov 27.
    Laboratory of Supramolecular and Bio-Nanomaterials (SupraBioNanoLab), Department of Chemistry, Materials, and Chemical Engineering "Giulio Natta", Politecnico di Milano, Via Luigi Mancinelli 7, Milano, I-20131, Italy.
    Amyloidogenic peptide fragment KLVFF (H2 N-Lys-Leu-Val-Phe-Phe-COOH, Aβ16-20 ), the core-sequence of the polypeptide Aβ40, is a well-studied model for amyloid formation. However, due to its low crystallinity, detailed atomic information of KLVFF structure is lacking. Here we report the high-resolution single-crystal X-ray structure of two monohalogenated KLVFF derivatives, KLVFF(I) and KLVFF(Br). Read More

    Peptide modulators of Rac1/Tiam1 protein-protein interaction: An alternative approach for cardiovascular diseases.
    Biopolymers 2017 Nov 27. Epub 2017 Nov 27.
    Department of Pharmaceutical Sciences, University of Milano, Milano, Italy.
    Rac1 GTPase interaction with guanine nucleotide exchange factor Tiam1 is involved in several cancer types and cardiovascular diseases. Although small molecules interfering with their protein-protein interaction (PPI) were identified and studied, the ability of small peptides and peptide mimics acting as Rac1/Tiam1 PPI inhibitors has not been yet explored. Using computational alanine scanning (CAS), the "hot" interfacial residues have been determined allowing the design of a small library of putative PPI inhibitors. Read More

    Probing the activity of a recombinant Zn2+ -transporting P-type ATPase.
    Biopolymers 2017 Nov 23. Epub 2017 Nov 23.
    Science for Life Laboratory, Department of Physics and Swedish e-Science Research Center, KTH Royal Institute of Technology, Solna, SE-171 21, Sweden.
    P-type ATPase proteins maintain cellular homeostasis and uphold critical concentration gradients by ATP-driven ion transport across biological membranes. Characterization of single-cycle dynamics by time-resolved X-ray scattering techniques in solution could resolve structural intermediates not amendable to for example crystallization or cryo-electron microscopy sample preparation. To pave way for such time-resolved experiments, we used biochemical activity measurements, Attenuated Total Reflectance (ATR) and time-dependent Fourier-Transform Infra-Red (FTIR) spectroscopy to identify optimal conditions for activating a Zn2+ -transporting Type-I ATPase from Shigella sonnei (ssZntA) at high protein concentration using caged ATP. Read More

    Design and development of low cost polyurethane biopolymer based on castor oil and glycerol for biomedical applications.
    Biopolymers 2017 Nov 21. Epub 2017 Nov 21.
    UCL Institute of Orthopaedics and Musculoskeletal Science, Division of Surgery & Interventional Science, University College London, London, United Kingdom.
    In the current study, we present the synthesis of novel low cost bio-polyurethane compositions with variable mechanical properties based on castor oil and glycerol for biomedical applications. A detailed investigation of the physicochemical properties of the polymer was carried out by using mechanical testing, ATR-FTIR, and X-ray photoelectron spectroscopy (XPS). Polymers were also tested in short term in-vitro cell culture with human mesenchymal stem cells to evaluate their biocompatibility for potential applications as biomaterial. Read More

    Structure-activity studies of peptidomimetics based on kinase-inhibitory region of suppressors of cytokine signaling 1.
    Biopolymers 2017 Nov 20. Epub 2017 Nov 20.
    Department of Pharmacy, CIRPEB: Centro Interuniversitario di Ricerca sui Peptidi Bioattivi- University of Naples "Federico II,", Naples, 80134, Italy.
    Suppressors of Cytokine Signaling (SOCS) proteins are negative regulators of JAK proteins that are receptor-associated tyrosine kinases, which play key roles in the phosphorylation and subsequent activation of several transcription factors named STATs. Unlike the other SOCS proteins, SOCS1 and 3 show, in the N-terminal portion, a small kinase inhibitory region (KIR) involved in the inhibition of JAK kinases. Drug discovery processes of compounds based on KIR sequence demonstrated promising in functional in vitro and in inflammatory animal models and we recently developed a peptidomimetic called PS5, as lead compound. Read More

    The burst-phase folding intermediate of ribonuclease H changes conformation over evolutionary history.
    Biopolymers 2017 Nov 20. Epub 2017 Nov 20.
    Department of Molecular and Cell Biology, University of California, Berkeley, California.
    The amino acid sequence encodes the energy landscape of a protein. Therefore, we expect evolutionary mutations to change features of the protein energy landscape, including the conformations adopted by a polypeptide as it folds to its native state. Ribonucleases H (RNase H) from Escherichia coli and Thermus thermophilus both fold via a partially folded intermediate in which the core region of the protein (helices A-D and strands 4-5) is structured. Read More

    Β-cyclodextrin encapsulated polyphenols as effective antioxidants.
    Biopolymers 2017 Nov 15. Epub 2017 Nov 15.
    Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur, 721302, India.
    Formation of dityrosine (DT) cross-linkages in proteins is one of the most widely used markers of oxidative stress. Ribonuclease A (RNase A) has 6 Tyr residues and shows a characteristic DT fluorescence peak upon oxidation in addition to major changes in its secondary structure. DT formation can be prevented by using polyphenols (GA, ECG, and EGCG) which are known to have strong antioxidant activity. Read More

    Differentiation potential of human adipose stem cells bioprinted with hyaluronic acid/gelatin-based bioink through microextrusion and visible light-initiated crosslinking.
    Biopolymers 2017 Nov 15. Epub 2017 Nov 15.
    Department of Materials Science and Engineering, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka, 560-8531, Japan.
    Bioprinting has a great potential to fabricate three-dimensional (3D) functional tissues and organs. In particular, the technique enables fabrication of 3D constructs containing stem cells while maintaining cell proliferation and differentiation abilities, which is believed to be promising in the fields of tissue engineering and regenerative medicine. We aimed to demonstrate the utility of the bioprinting technique to create hydrogel constructs consisting of hyaluronic acid (HA) and gelatin derivatives through irradiation by visible light to fabricate 3D constructs containing human adipose stem cells (hADSCs). Read More

    Conformational properties, membrane interaction, and antibacterial activity of the peptaibiotic chalciporin A: Multitechnique spectroscopic and biophysical investigations on the natural compound and labeled analogs.
    Biopolymers 2017 Nov 11. Epub 2017 Nov 11.
    Institute of Biomolecular, Chemistry, Padova Unit, CNR, Padova, 35131, Italy.
    In this work, an extensive set of spectroscopic and biophysical techniques (including FT-IR absorption, CD, 2D-NMR, fluorescence, and CW/PELDOR EPR) was used to study the conformational preferences, membrane interaction, and bioactivity properties of the naturally occurring synthetic 14-mer peptaibiotic chalciporin A, characterized by a relatively low (≈20%), uncommon proportion of the strongly helicogenic Aib residue. In addition to the unlabeled peptide, we gained in-depth information from the study of two labeled analogs, characterized by one or two residues of the helicogenic, nitroxyl radical-containing TOAC. All three compounds were prepared using the SPPS methodology, which was carefully modified in the course of the syntheses of TOAC-labeled analogs in view of the poorly reactive α-amino function of this very bulky residue and the specific requirements of its free-radical side chain. Read More

    Peptide strand length controls the energetics of self-assembly and morphology of β-sheet fibrils.
    Biopolymers 2017 Nov 11. Epub 2017 Nov 11.
    School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT.
    Self-assembling peptides can be used as versatile, natural, and multifunctional building blocks to produce a variety of well-defined nanostructures, materials and devices for applications in medicine and nanotechnology. Here, we concentrate on the 1D self-assembly of de novo designed Px-2 peptide β-strands into anti-parallel β-sheet tapes and higher order aggregates. We study six members of the Px-2 family, ranging from 3 amino acids (aa) to 13 aa in length, using a range of complementary experimental techniques, computer simulation and theoretical statistical mechanics. Read More

    Release kinetics of somatostatin from self-assembled nanostructured hydrogels.
    Biopolymers 2017 Nov 11. Epub 2017 Nov 11.
    Discipline of Pharmacy, School of Health and Biomedical Sciences, RMIT University, Bundoora, Victoria, 3083, Australia.
    Somatostatin-14 is a native neuropeptide with widespread functions in the body. Self-assembly of somatostatin-14 into amyloid-like nanofibrils has been previously demonstrated in aqueous media. We here hypothesize that the somatostatin nanofibrils can form a stable depot that release monomers in a controlled manner. Read More

    Enhanced tissue adhesiveness of injectable gelatin hydrogels through dual catalytic activity of horseradish peroxidase.
    Biopolymers 2017 Nov 6. Epub 2017 Nov 6.
    Department of Molecular Science and Technology, Ajou University, Suwon, Republic of Korea.
    Development of bioadhesives with tunable mechanical strength, high adhesiveness, biocompatibility, and injectability is greatly desirable in all surgeries to replace or complement the sutures and staples. Herein, the dual catalytic activity of horseradish peroxidase is exploited to in situ form the hydroxyphenyl propionic acid-gelatin/thiolated gelatin (GH/GS) adhesive hydrogels including two alternative crosslinks (phenol-phenol and disulfide bonds) with fast gelation (few seconds - several minutes) and improved physicochemical properties. Their elastic moduli increase from 6. Read More

    Esculentin-1a derived peptides kill Pseudomonas aeruginosa biofilm on soft contact lenses and retain antibacterial activity upon immobilization to the lens surface.
    Biopolymers 2017 Oct 31. Epub 2017 Oct 31.
    Laboratory affiliated to Pasteur Italia-Fondazione Cenci Bolognetti, Department of Biochemical Sciences, Sapienza University of Rome, Rome, Italy.
    Contact lens (CL) wear is a risk factor for development of microbial keratitis, a vision threatening infection of the eye. Adverse events associated with colonization of lenses, especially by the multi-drug resistant and biofilm forming bacterium Pseudomonas aeruginosa remain a major safety issue. Therefore, novel strategies and compounds to reduce the onset of CL-associated ocular infections are needed. Read More

    The polypeptide biophysics of proline/alanine-rich sequences (PAS): Recombinant biopolymers with PEG-like properties.
    Biopolymers 2017 Oct 27. Epub 2017 Oct 27.
    Lehrstuhl für Biologische Chemie, Technische Universität München, 85354, Freising (Weihenstephan), Germany.
    PAS polypeptides comprise long repetitive sequences of the small L-amino acids proline, alanine and/or serine that were developed to expand the hydrodynamic volume of conjugated pharmaceuticals and prolong their plasma half-life by retarding kidney filtration. Here, we have characterized the polymer properties both of the free polypeptides and in fusion with the biopharmaceutical IL-1Ra. Data from size exclusion chromatography, dynamic light scattering, circular dichroism spectroscopy and quantification of hydrodynamic and polar properties demonstrate that the biosynthetic PAS polypeptides exhibit random coil behavior in aqueous solution astonishingly similar to the chemical polymer poly-ethylene glycol (PEG). Read More

    Probing the dynamics of restriction endonuclease NgoMIV-DNA interaction by single-molecule FRET.
    Biopolymers 2017 Dec 27;107(12). Epub 2017 Oct 27.
    Institute of Physics, Center for Physical Sciences and Technology, Savanoriu 231, Vilnius, 02300, Lithuania.
    Many type II restriction endonucleases require two copies of their recognition sequence for optimal activity. Concomitant binding of two DNA sites by such an enzyme produces a DNA loop. Here we exploit single-molecule Förster resonance energy transfer (smFRET) of surface-immobilized DNA fragments to study the dynamics of DNA looping induced by tetrameric endonuclease NgoMIV. Read More

    Exploring the influence of hyperthermophilic protein Ssh10b on the stability and conformation of RNA by molecular dynamics simulation.
    Biopolymers 2017 Oct 25. Epub 2017 Oct 25.
    Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, International Joint Research Laboratory of Nano-Micro Architecture Chemistry, Jilin University, Changchun, 130023, People's Republic of China.
    The hyperthermophilic Ssh10b from Sulfolobus shibatae is a member of the Sac10b family, which binds RNA in vivo as a physiological substrate, and it has been postulated to play a key role in chromosomal organization in Archaea. Even though the crystal structure of Ssh10b-RNA was resolved successively by X-ray diffraction (Protein Data Bank [PDB] code: 3WBM), the detailed dynamic characteristics of Ssh10b-RNA are still unclear. In this study, molecular dynamics (MDs) simulations at 6 temperatures (300, 350, 375, 400, 450, and 500 K) and molecular mechanics Generalized-Born surface area (MM-GB/SA) free energy calculations were performed to investigate the mechanism of how Ssh10b protects and stabilizes RNA. Read More

    Effect of heavy water on the conformational stability of globular proteins.
    Biopolymers 2017 Oct 25. Epub 2017 Oct 25.
    Dipartimento di Scienze e Tecnologie, Università del Sannio, Via Port'Arsa 11, Benevento, 82100, Italy.
    It is well established from the experimental point of view that the native state of globular proteins is more stable in heavy water than in water. No robust explanation, however, has been provided up to now. The application of the theoretical approach, originally devised to rationalize the general occurrence of cold denaturation, indicates that the magnitude of the solvent-excluded volume effect is slightly smaller in heavy water than in water and cannot explain the observed protein stabilization. Read More

    Polypeptoid polymers: Synthesis, characterization, and properties.
    Biopolymers 2017 Oct 25. Epub 2017 Oct 25.
    Department of Chemistry and Macromolecular Studies Group, Louisiana State University, Baton Rouge, 70803, Los Angeles.
    Polypeptoids, a class of peptidomimetic polymers, have emerged at the forefront of macromolecular and supramolecular science and engineering as the technological relevance of these polymers continues to be demonstrated. The chemical and structural diversity of polypeptoids have enabled access to and adjustment of a variety of physicochemical and biological properties (eg, solubility, charge characteristics, chain conformation, HLB, thermal processability, degradability, cytotoxicity and immunogenicity). These attributes have made this synthetic polymer platform a potential candidate for various biomedical and biotechnological applications. Read More

    Synthesis and structure analysis of ferrocene-containing pseudopeptides.
    Biopolymers 2017 Oct 23. Epub 2017 Oct 23.
    Dipartimento di Chimica "Giacomo Ciamician", Università di Bologna - Via Selmi, 2, Bologna, 40126, Italy.
    Ferrocene with its aromaticity and facile redox properties is an attractive moiety to be incorporated into functional moieties. Medicinal applications of ferrocene are well known and ferrocene itself shows cytotoxic and antianemic properties. In this article, we will describe the synthesis and the structure analysis of two pseudopeptides containing a ferrocene moiety as N-terminal group. Read More

    Doxorubicin hinders DNA condensation promoted by the protein bovine serum albumin (BSA).
    Biopolymers 2017 Dec 23;107(12). Epub 2017 Oct 23.
    Departamento de Física, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil.
    In this work, we have studied the interaction between the anticancer drug doxorubicin (doxo) and condensed DNA, using optical tweezers. To perform this task, we use the protein bovine serum albumin (BSA) in the working buffer to mimic two key conditions present in the real intracellular environment: the condensed state of the DNA and the abundant presence of charged macromolecules in the surrounding medium. In particular, we have found that, when doxo is previously intercalated in disperse DNA, the drug hinders the DNA condensation process upon the addition of BSA in the buffer. Read More

    Process development of a FGF21 protein-antibody conjugate.
    Biopolymers 2017 Sep 26. Epub 2017 Sep 26.
    Pfizer Inc.-BioTherapeutics Pharmaceutical Sciences: Bioprocess R&D, 700 Chesterfield Parkway West, Chesterfield, Missouri, 63017.
    A scalable, viable process was developed for the Fibroblast Growth Factor 21 (FGF21) protein-antibody conjugate, CVX-343, an extended half-life therapeutic for the treatment of metabolic disease. CVX-343 utilizes the CovX antibody scaffold technology platform that was specifically developed for peptide and protein half-life extension. CVX-343 is representative of a growing number of complex novel peptide- and protein-based bioconjugate molecules currently being explored as therapeutic candidates. Read More

    Antimicrobial activity of lysozyme isoforms: Key molecular features.
    Biopolymers 2017 Dec 25;107(12). Epub 2017 Sep 25.
    STLO, UMR1253, Agrocampus Ouest, INRA, Rennes, F-35, France.
    Increasing bacterial resistance towards antibiotics has stimulated research for novel antimicrobials. Proteins acting on bacterial membranes could be a solution. Lysozyme has been proven active against E. Read More

    Highly efficient antibacterial diblock copolypeptides based on lysine and phenylalanine.
    Biopolymers 2017 Nov 19;107(11). Epub 2017 Sep 19.
    School of Materials Science and Engineering, Tongji University, 4800 Caoan Road, Shanghai, 201804, China.
    A series of amphiphilic diblock copolypeptides (K30 -b-F15 , K30 -b-F30 , and K30 -b-F45 ) were synthesized via N-carboxy-α-amino-anhydride ring-opening polymerization. The copolypeptides had excellent antibacterial efficacy to both Gram positive (S. aureus) and Gram negative (E. Read More

    Thermal melt circular dichroism spectroscopic studies for identifying stabilising amphipathic molecules for the voltage-gated sodium channel NavMs.
    Biopolymers 2017 Sep 19. Epub 2017 Sep 19.
    Institute of Structural and Molecular Biology, Birkbeck College, University of London, London, United Kingdom.
    Purified integral membrane proteins require amphipathic molecules to maintain their solubility in aqueous solutions. These complexes, in turn, are used in studies to characterise the protein structures by a variety of biophysical and structural techniques, including spectroscopy, crystallography, and cryo-electron microscopy. Typically the amphilphiles used have been detergent molecules, but more recently they have included amphipols, which are polymers of different sizes and compositions designed to create smaller, more well-defined solubilised forms of the membrane proteins. Read More

    Structural insight into the XTACC3/XMAP215 interaction from CD and NMR studies on model peptides.
    Biopolymers 2017 Nov 18;107(11). Epub 2017 Sep 18.
    Department of Biological Physical Chemistry, IQFR-CSIC, Madrid, 28006, Spain.
    TACC3 is a centrosomal adaptor protein that plays important roles during mitotic spindle assembly. It interacts with chTOG/XMAP215, which catalyzes the addition of tubulin dimers during microtubule growth. A 3D coiled-coil model for this interaction is available but the structural details are not well described. Read More

    Synthesis and gelation of copolypept(o)ides with random and block structure.
    Biopolymers 2017 Oct 18;107(10). Epub 2017 Aug 18.
    Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai, 200237, China.
    Copolypept(o)ides of polysarcosine (PSar) and poly(N-isopropyl-L-glutamine) (PIGA) with random and block sequence structures were synthesized by ring-opening polymerization (ROP) of sarcosine N-carboxyanhydrides (Sar-NCA) and γ-benzyl-l-glutamate N-carboxyanhydrides (BLG-NCA) and post modification. With different distribution of Sar along the main chain, H-bonding pattern and secondary structure of polypeptides were turned, as well as aggregation and gelation behavior. Both copolypept(o)ides formed hydrogels above their critical gelation concentrations (CGCs) without thermo-sensitivity, which was normally reserved for PEG copolypeptides (eg, PEG-b-PIGA). Read More

    Design of modular dual enzyme-responsive peptides.
    Biopolymers 2017 Sep 11;108(5). Epub 2017 Aug 11.
    Department of Chemistry and Biochemistry and California NanoSystems Institute, University of California, 607 Charles E. Young Drive East, Los Angeles, California, 90095.
    Dual enzyme-responsive peptides were synthesized by masking the ɛ-amine of lysine with various enzyme substrates. Enzymatic cleavage of these sequences unmasked the ɛ-amine, allowing for further digestion by a second enzyme, which was monitored colorimetrically. This modular peptide design should provide substrates for a large combination of clinically relevant enzymes. Read More

    Homo- and heteropolymer self-assembly of recombinant trichocytic keratins.
    Biopolymers 2017 Oct 24;107(10). Epub 2017 Jul 24.
    Department of Chemistry and Macromolecules Innovation Institute, Virginia Tech, Blacksburg, Virginia, 24060.
    In the past two decades, keratin biomaterials have shown impressive results as scaffolds for tissue engineering, wound healing, and nerve regeneration. In addition to its intrinsic biocompatibility, keratin interacts with specific cell receptors eliciting beneficial biochemical cues. However, during extraction from natural sources, such as hair and wool fibers, natural keratins are subject to extensive processing conditions that lead to formation of unwanted by-products. Read More

    Ensemble characterization of an intrinsically disordered FG-Nup peptide and its F>A mutant in DMSO-d6.
    Biopolymers 2017 Nov 22;108(6). Epub 2017 Jul 22.
    Department of Chemistry, California State University, Fresno, California, 93740.
    Intrinsically disordered proteins (IDP) lack a well-defined 3D-structure under physiological conditions, yet, the inherent disorder represented by an ensemble of conformation plays a critical role in many cellular and regulatory processes. Nucleoporins, or Nups, are the proteins found in the nuclear pore complex (NPC). The central pore of the NPC is occupied by Nups, which have phenylalanine-glycine domain repeats and are intrinsically disordered, and therefore are termed FG-Nups. Read More

    Fusion of plectasin derivative NZ2114 with hydrophilic random coil polypeptide: Recombinant production in Pichia pastoris and antimicrobial activity against clinical strain MRSA.
    Biopolymers 2017 Jun 12. Epub 2017 Jun 12.
    Centro de Análises, Proteômicas e Bioquímicas, Programa de Pós Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília, Brazil.
    One of the roadblocks towards the practical use of antimicrobial peptides for medical use is their relatively high cost when synthesized chemically. Effective recombinant production has only been successful in some cases, such as the previously reported production in Pichia pastoris of the antimicrobial plectasin derivative peptide NZ2114. The same production host has also been used extensively to produce so-called protein-polymers: sequences that consist of repetitions of simple amino acid motifs found in structural proteins such as collagen and elastin, and that can be designed to self-assemble in micelles, fibers and hydrogels. Read More

    Self-assembly of t-butyloxycarbonyl protected dipeptide methyl esters composed of leucine, isoleucine, and valine into highly organized structures from alcohol and aqueous alcohol mixtures.
    Biopolymers 2017 Nov;108(6)
    CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad, Telangana, 500007, India.
    Short peptides composed of phenylalanine and sequences derived from amyloidogenic peptides have the ability to self-assemble to form nanostructures including hydrogels. The self-assembly of peptides composed of only hydrophobic amino acids and aliphatic protecting groups have not been investigated in detail. We have examined various aspects of nanostructures formed by N-terminal t-butyloxycarbonyl-protected aliphatic dipeptide methyl esters dissolved in various solvents. Read More

    Activity of synthetic peptides against Chlamydia.
    Biopolymers 2017 Nov;108(6)
    Centre of Proteomics and Biochemistry, Catholic University of Brasilia, Brazil.
    The in vitro activity of six synthetic peptides against 36 strains of Chlamydia from different origins was investigated. Clavanin MO (CMO) proved to be the most active peptide, reducing the inclusion number of all Chlamydia strains from eight different species tested by ≥50% at 10 µg mL-1 . Mastoparan L showed an equal activity against C. Read More

    Fabrication of elastomeric silk fibers.
    Biopolymers 2017 Sep;107(9)
    Department of Biomedical Engineering, Tufts University, Medford, Massachusetts.
    Methods to generate fibers from hydrogels, with control over mechanical properties, fiber diameter, and crystallinity, while retaining cytocompatibility and degradability, would expand options for biomaterials. Here, we exploited features of silk fibroin protein for the formation of tunable silk hydrogel fibers. The biological, chemical, and morphological features inherent to silk were combined with elastomeric properties gained through enzymatic crosslinking of the protein. Read More

    Design and chemical syntheses of potent matriptase-2 inhibitors based on trypsin inhibitor SFTI-1 isolated from sunflower seeds.
    Biopolymers 2017 Nov;108(6)
    Department of Molecular Biochemistry, Faculty of Chemistry, University of Gdansk, ul. Wita Stwosza 63, Gdansk, 80-308, Poland.
    Matriptase-2 plays a pivotal role in keeping iron concentrations within a narrow physiological range in humans. The opportunity to reduce matriptase-2 proteolytic activity may open a novel possibility to treat iron overload diseases, such as hereditary hemochromatosis and thalassemia. Here, we present 23 new analogues of trypsin inhibitor SFTI-1 designed to inhibit human matriptase-2. Read More

    Inhibition of melanoma metastasis by dual-peptide PLGA NPS.
    Biopolymers 2017 Sep;108(5)
    Institute of Science and Technology, Federal University of São Paulo, São José dos Campos, SP, Brazil.
    Despite the positive results observed in vitro and in vivo, clinical trials with bioactive peptides are generally hampered by their fast degradation in the biological system. Two bioactive peptides, P20 (CSSRTMHHC) and the combined peptide C (CVNHPAFACGYGHTMYYHHYQHHL) have been identified as anticancer therapeutics. Combined peptide C consists of peptide C (CVNHPAFAC), a tumor-homing peptide, conjugated to the antiangiogenic peptide HTMYYHHYQHHL with a GYG. Read More

    Structural and functional study of a simple, rapid, and label-free DNAzyme-based DNA biosensor for optimization activity.
    Biopolymers 2017 Oct;107(10)
    Department of Nanobiotechnology, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran.
    Peroxidase-mimicking DNAzyme has a potential to self-assemble into a G-quadruplex and shows peroxidase activity. In comparison to proteins, peroxidase-mimicking DNAzyme is less expensive and more stable. Herein, it is used in fabricating non-labeling biosensors. Read More

    Convergent mechanisms favor fast amyloid formation in two lambda 6a Ig light chain mutants.
    Biopolymers 2017 Aug;107(8)
    Centro de Investigación en Dinámica Celular-IICBA, Universidad Autónoma del Estado de Morelos, Cuernavaca, Morelos, México.
    Extracellular deposition as amyloids of immunoglobulin light chains causes light chain amyloidosis. Among the light chain families, lambda 6a is one of the most frequent in light chain amyloidosis patients. Its germline protein, 6aJL2, and point mutants, R24G and P7S, are good models to study fibrillogenesis, because their stability and fibril formation characteristics have been described. Read More

    Alanine scan of the opioid peptide dynorphin B amide.
    Biopolymers 2017 Sep;108(5)
    Department of Medicinal Chemistry, The University of Kansas, Lawrence, Kansas, 66045.
    To date structure-activity relationship (SAR) studies of the dynorphins (Dyn), endogenous peptides for kappa opioid receptors (KOR), have focused almost exclusively on Dyn A with minimal studies on Dyn B. While both Dyn A and Dyn B have identical N-terminal sequences, their C-terminal sequences differ, which could result in differences in pharmacological activity. We performed an alanine scan of the non-glycine residues up through residue 11 of Dyn B amide to explore the roles of these side chains in the activity of Dyn B. Read More

    Lysine to arginine mutagenesis of chlorotoxin enhances its cellular uptake.
    Biopolymers 2017 Sep;108(5)
    Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia.
    Chlorotoxin (CTX), a disulfide-rich peptide from the scorpion Leiurus quinquestriatus, has several promising biopharmaceutical properties, including preferential affinity for certain cancer cells, high serum stability, and cell penetration. These properties underpin its potential for use as a drug design scaffold, especially for the treatment of cancer; indeed, several analogs of CTX have reached clinical trials. Here, we focus on its ability to internalize into cells-a trait associated with a privileged subclass of peptides called cell-penetrating peptides-and whether it can be improved through conservative substitutions. Read More

    Identification and characterization of multifunctional cationic and amphipathic peptides from soybean proteins.
    Biopolymers 2017 Jul;108(4)
    Department of Materials Science and Technology, Graduate School of Science and Technology, Niigata University, Niigata, 950-2181, Japan.
    In this study, we identified and chemically synthesized three cationic and amphipathic peptides (Glycinin-17, BCAS-16, and BCBS-11) from soybean proteins. These peptides had high isoelectric points, high positive net charges, and included multiple hydrophobic amino acids. Subsequently, we identified multiple functions of these peptides, including antimicrobial, lipopolysaccharide-neutralizing, and angiogenic activities, and examined their cytotoxic activities against mammalian red blood cells. Read More

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