19 results match your criteria hu-a chains

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N-Terminal Extensions Appear to Frustrate HU Heterodimer Formation by Strengthening Intersubunit Contacts and Blocking the Formation of a Heterotetrameric Intermediate.

Biochemistry 2021 Jun 21;60(23):1836-1852. Epub 2021 May 21.

Centre for Protein Science, Design and Engineering (CPSDE), Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Knowledge City, Sector-81, SAS Nagar, Punjab 140306, India.

HU is a bacterial nucleoid-associated protein. Two homologues, known as HU-A, and HU-B, are found in within which the early, late, and stationary phases of growth are dominated by HU-AA, HU-BB, and HU-AB dimers, respectively. Here, using genetic manipulation, mass spectrometry, spectroscopy, chromatography, and electrophoretic examination of glutaraldehyde-mediated cross-linking of subunits, in combination with experiments involving mixing, co-expression, unfolding, and refolding of HU chains, we show that the spontaneous formation of HU-AB heterodimers that is reported to occur upon mixing of wild-type HU-AA and HU-BB homodimers does not occur if chains possess N-terminal extensions. Read More

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HU-AB simulacrum: Fusion of HU-B and HU-A into HU-B-A, a functional analog of the Escherichia coli HU-AB heterodimer.

Biochem Biophys Res Commun 2021 Jun 5;560:27-31. Epub 2021 May 5.

Centre for Protein Science, Design and Engineering (CPSDE), Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Knowledge City, Sector-81, SAS Nagar, Punjab, 140306, India. Electronic address:

In enteric bacteria such as Escherichia coli, there are two homologs of the DNA-binding nucleoid associated protein (NAP) known as HU. The two homologs are known as HU-A and HU-B, and exist either in the form of homodimers (HU-AA, or HU-BB) or as heterodimers (HU-AB), with different propensities to form higher-order oligomers. The three different dimeric forms dominate different stages of bacterial growth, with the HU-AB heterodimer dominating cultures in the stationary phase. Read More

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Electrostatic self-assembled nanoparticles based on spherical polyelectrolyte brushes for magnetic resonance imaging.

Dalton Trans 2018 Jun;47(23):7663-7668

Shanghai Key Laboratory of Advanced Polymeric Materials, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai, 200237, China.

Magnetic resonance imaging (MRI) is one of the most important medical imaging techniques for clinical diagnosis. Contrast agents (CAs) are commonly necessarily used to enhance the imaging quality of MRI and differentiate diseased tissues from normal ones. Herein, we introduced a macromolecular carrier, spherical polyelectrolyte brushes (SPBs), which consists of a solid polystyrene (PS) core and polyacrylic acid (PAA) chains as a brush layer to host Gd(iii) complexes. Read More

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Construction of Polyarylenes with Various Structural Features via Bergman Cyclization Polymerization.

Top Curr Chem (Cham) 2017 Jun 22;375(3):60. Epub 2017 May 22.

Shanghai Key Laboratory of Advanced Polymeric Materials, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai, 200237, China.

Synthetic polymer chemistry is a fundamental part of polymer science, and highly efficient polymerization reactions are essential for the synthesis of high-performance polymers. Development of new synthetic methods for emerging polymer science is of great importance in this regard. Bergman cyclization is a chemical process in which highly reactive aryl diradicals form from enediyne precursors, having a strong impact in a number of fields including pharmaceutics, synthetic chemistry, and materials science. Read More

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HP-DO3A-based amphiphilic MRI contrast agents and relaxation enhancement through their assembly with polyelectrolytes.

J Mater Chem B 2016 Dec 26;4(45):7241-7248. Epub 2016 Oct 26.

Shanghai Key Laboratory of Advanced Polymeric Materials, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai, 200237, China.

HP-DO3A-based cationic amphiphilic Gd(iii) complexes bearing quaternary ammonium salts of different alkyl chain lengths were synthesized. The structures of the intermediates, the ligands and the Gd(iii) complexes were characterized by H NMR, C NMR, ESI and MALDI-TOF mass spectrometry. Relaxation studies of the amphiphilic Gd(iii) complexes revealed that long alkyl chains facilitated the formation of micelles in an aqueous solution and afforded high relaxivity. Read More

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December 2016

Kaleidoscope of quantum phases in a long-range interacting spin-1 chain.

Phys Rev B 2016 ;93

Joint Quantum Institute, NIST/University of Maryland, College Park, Maryland 20742, USA.

Motivated directly by recent trapped-ion quantum simulation experiments, we carry out a comprehensive study of the phase diagram of a spin-1 chain with XXZ-type interactions that decay as 1/ , using a combination of finite and infinite-size DMRG calculations, spin-wave analysis, and field theory. In the absence of long-range interactions, varying the spin-coupling anisotropy leads to four distinct and well-studied phases: a ferromagnetic Ising phase, a disordered XY phase, a topological Haldane phase, and an antiferromagnetic Ising phase. If long-range interactions are antiferromagnetic and thus frustrated, we find primarily a quantitative change of the phase boundaries. Read More

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January 2016

4-Amino-2-trifluoromethyl-phenyl retinate inhibits the migration of BGC-823 human gastric cancer cells by downregulating the phosphorylation level of MLC II.

Oncol Rep 2014 Oct 18;32(4):1473-80. Epub 2014 Jul 18.

Institute of Clinical Pharmacology, Anhui Medical University, Hefei, Anhui 230032, P.R. China.

4-Amino-2-trifluoromethyl-phenyl retinate (ATPR) is a novel all-trans retinoic acid (ATRA) derivative which was reported to have a superior antitumor effect in breast cancer cells. However, little is known about its antitumor effects on human gastric cancer cells and the mechanisms have not been fully elucidated. The results of the present study suggest that in the human gastric carcinoma cell line BGC-823, ATPR plays a more effective role than ATRA at the same dose in inhibiting proliferation, migration and inducing differentiation after the same treatment time. Read More

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October 2014

[Correlation of HLA-DRB1 gene polymorphism and aplastic anemia in Xinjiang Han people].

Xi Bao Yu Fen Zi Mian Yi Xue Za Zhi 2014 Feb;30(2):188-90

Blood Center, First Affiliated Hospital, Xinjiang Medical University, Urumqi 830054, China.

Objective: To investigate the correlation between the human leukocyte antigen (HLA) DRB1 and the aplastic anemia (AA).

Methods: A total of 243 Han ethnic people in Xinjiang were enrolled for this study. Among them, 43 people were diagnosed as AA and the other 200 were healthy controls. Read More

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February 2014

Attaching double chain cationic Gd(iii)-containing surfactants on nanosized colloids for highly efficient MRI contrast agents.

J Mater Chem B 2013 Oct 28;1(40):5443-5449. Epub 2013 Aug 28.

Shanghai Key Laboratory of Advanced Polymeric Materials, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai, 200237, China.

A new Gd(iii)-based metallosurfactant with double quaternary-ammonium-containing long alkyl chains was developed and subjected to the miniemulsion polymerization of vinyl monomers, giving nanosized colloids (50-110 nm) with narrow size distribution. The size of the colloid particles can be easily tuned by adjusting the feeding ratio of metallosurfactant to monomer. SEM and XPS analysis showed that the Gd(iii) complexes were attached on the surface of the colloids. Read More

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October 2013

On-surface formation of one-dimensional polyphenylene through Bergman cyclization.

J Am Chem Soc 2013 Jun 28;135(23):8448-51. Epub 2013 May 28.

College of Materials Science and Engineering, Key Laboratory for Advanced Civil Engineering Materials (Ministry of Education), Tongji University, Caoan Road 4800, Shanghai 201804, PR China.

On-surface fabrication of covalently interlinked conjugated nanostructures has attracted significant attention, mainly because of the high stability and efficient electron transport ability of these structures. Here, from the interplay of scanning tunneling microscopy imaging and density functional theory calculations, we report for the first time on-surface formation of one-dimensional polyphenylene chains through Bergman cyclization followed by radical polymerization on Cu(110). The formed surface nanostructures were further corroborated by the results for the ex situ-synthesized molecular product after Bergman cyclization. Read More

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High-temperature spin crossover behavior in a nitrogen-rich Fe(III)-based system.

Inorg Chem 2013 Feb 6;52(4):1825-31. Epub 2013 Feb 6.

Department of Chemistry, University of Ottawa, 10 Marie Curie, Ottawa, ON, K1N6N5, Canada.

A nitrogen-rich ligand bis(1H-tetrazol-5-yl)amine (H(3)bta) was employed to isolate a new Fe(III) complex, Na(2)NH(4)[Fe(III)(Hbta)(3)]·3DMF·2H(2)O (1). Single crystal X-ray diffraction revealed that complex 1 consists of Fe(III) ions in an octahedral environment where each metal ion is coordinated by three Hbta(2-) ligands forming the [Fe(III)(Hbta)(3)](3-) core. Each unit is linked to two one-dimensional (1-D) Na(+)/solvent chains creating a two-dimensional (2-D) network. Read More

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February 2013

Hydrogen-bonding-induced complexation of polydimethylsiloxane-graft-poly(ethylene oxide) and poly(acrylic acid)-block-polyacrylonitrile micelles in water.

Langmuir 2010 Sep;26(18):14502-8

School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China.

Polydimethylsiloxane-graft-poly(ethylene oxide) (PDMS-g-PEO) copolymers form micelles in water with PDMS as the core and PEO as the corona. The introduction of poly(acrylic acid)-block-polyacrylonitrile (PAA-b-PAN) block copolymers in water leads to the formation of micellar complexes due to the hydrogen bonding between carboxyl groups and ether oxygens among the PAA and PEO chains in the corona of the micelles. The effects of pH, molar ratios (r) of PAA/PEO, and the standing time on the directly mixing these two micelles in water have been investigated using laser light scattering (LLS) and transmission electron microscopy (TEM). Read More

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September 2010

Spectroscopic characterization of carbon chains in nanostructured tetrahedral carbon films synthesized by femtosecond pulsed laser deposition.

J Chem Phys 2007 Apr;126(15):154705

Department of Physics, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, Canada.

A comparative study of carbon bonding states and Raman spectra is reported for amorphous diamondlike carbon films deposited using 120 fs and 30 ns pulsed laser ablation of graphite. The presence of sp(1) chains in femtosecond carbon films is confirmed by the appearance of a broad excitation band at 2000-2200 cm(-1) in UV-Raman spectra. Analysis of Raman spectra indicates that the concentrations of sp(1)-, sp(2)-, and sp(3)-bonded carbon are approximately 6%, approximately 43%, and approximately 51%, respectively, in carbon films prepared by femtosecond laser ablation. Read More

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A homochiral porous metal-organic framework for highly enantioselective heterogeneous asymmetric catalysis.

J Am Chem Soc 2005 Jun;127(25):8940-1

Department of Chemistry, CB#3290, University of North Carolina, Chapel Hill, North Carolina 27599, USA.

A homochiral porous noninterpenetrating metal-organic framework (MOF), 1, was constructed by linking infinite 1D [Cd(mu-Cl)2]n zigzag chains with axially chiral bipyridine bridging ligands containing orthogonal secondary functional groups. The secondary chiral dihydroxy groups accessible via the large open channels in 1 were utilized to generate a heterogeneous asymmetric catalyst for the addition of diethyzinc to aromatic aldehydes to afford chiral secondary alcohols at up to 93% enantiomeric excess (ee). Control experiments with dendritic aromatic aldehydes of different sizes indicate that the heterogeneous asymmetric catalyst derived from 1 is both highly active and enantioselective as a result of the creation of readily accessible, uniform active catalyst sites inside the porous MOF. Read More

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Mutations in human nonmuscle myosin IIA found in patients with May-Hegglin anomaly and Fechtner syndrome result in impaired enzymatic function.

J Biol Chem 2002 Nov 16;277(48):46512-7. Epub 2002 Sep 16.

Laboratory of Molecular Cardiology, NHLBI, National Institutes of Health, Bethesda, Maryland 20892-1762, USA.

A family of autosomal-dominant diseases including May-Hegglin anomaly, Fechtner syndrome, Sebastian syndrome, Alport syndrome, and Epstein syndrome are commonly characterized by giant platelets and thrombocytopenia. In addition, there may be leukocyte inclusions, deafness, cataracts, and nephritis, depending on the syndrome. Mutations in the human nonmuscle myosin IIA heavy chain gene (MYH9) have been linked to these diseases. Read More

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November 2002

Influence of N-linked oligosaccharide chains on the processing, cell surface expression and function of the measles virus fusion protein.

J Gen Virol 1995 Mar;76 ( Pt 3):705-10

Microbiology and Tumorbiology Centre, Karolinska Institute, Stockholm, Sweden.

The fusion (F) glycoprotein of measles virus, a structural component of the virion envelope, contains four potential sites for attachment of N-linked oligosaccharides. Three are located in the F2 subunit of the protein and one in the signal peptide. Four mutants were constructed by oligonucleotide-directed mutagenesis, in each case changing one N-linked glycosylation site from Asn-X-Ser/Thr to Ser-X-Ser/Thr. Read More

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Role of N-linked oligosaccharide chains in the processing and antigenicity of measles virus haemagglutinin protein.

J Gen Virol 1994 May;75 ( Pt 5):1043-52

Department of Virology, School of Medicine, Karolinska Institute, Stockholm, Sweden.

The effects of N-linked oligosaccharides on the haemagglutinin (H) protein of measles virus (MV) were assessed with respect to the processing and antigenicity of the molecule. The functional glycosylation sites on the H protein were determined by eliminating each of the five potential positions, Asn-168, Asn-187, Asn-200, Asn-215 and Asn-238, for N-linked glycosylation by oligonucleotide-directed mutagenesis on a cDNA clone. Expression of the mutant H proteins in BHK-21 cells by a recombinant vaccinia virus encoding T7 polymerase indicated that the first four sites were used in the H glycoprotein for the addition of N-linked oligosaccharide chains. Read More

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Effect of age on the expressed B cell repertoire: role of B cell subsets.

Int Immunol 1993 Sep;5(9):1035-9

Department of Medicine, Cornell University Medical College, New York, NY 10021.

Aged humans and experimental animals are impaired in their responses to most foreign antigens although they produce greater amounts of autoantibodies. We have examined the effect of age on the production of antibodies to a prototypic foreign antigen, sheep erythrocytes (SRBC), and to a prototypic autoantigen, bromelain-treated mouse erythrocytes (BrMRBC), in young and old mice before and after immunization with SRBC. Old mice express more anti-BrMRBC plaque-forming cell (PFC) antibodies before and an even greater number after immunization with SRBC than young mice. Read More

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September 1993
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