Publications by authors named "Danielle H Dube"

21 Publications

  • Page 1 of 1

Dismantling the bacterial glycocalyx: Chemical tools to probe, perturb, and image bacterial glycans.

Bioorg Med Chem 2021 Jul 7;42:116268. Epub 2021 Jun 7.

Department of Chemistry & Biochemistry, Bowdoin College, 6600 College Station, Brunswick, ME 04011, USA. Electronic address:

The bacterial glycocalyx is a quintessential drug target comprised of structurally distinct glycans. Bacterial glycans bear unusual monosaccharide building blocks whose proper construction is critical for bacterial fitness, survival, and colonization in the human host. Despite their appeal as therapeutic targets, bacterial glycans are difficult to study due to the presence of rare bacterial monosaccharides that are linked and modified in atypical manners. Their structural complexity ultimately hampers their analytical characterization. This review highlights recent advances in bacterial chemical glycobiology and focuses on the development of chemical tools to probe, perturb, and image bacterial glycans and their biosynthesis. Current technologies have enabled the study of bacterial glycosylation machinery even in the absence of detailed structural information.
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http://dx.doi.org/10.1016/j.bmc.2021.116268DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8276522PMC
July 2021

Metabolic Glycan Labeling-Based Screen to Identify Bacterial Glycosylation Genes.

ACS Infect Dis 2020 12 13;6(12):3247-3259. Epub 2020 Nov 13.

Department of Chemistry & Biochemistry, Bowdoin College, 6600 College Station, Brunswick, Maine 04011, United States.

Bacterial cell surface glycans are quintessential drug targets due to their critical role in colonization of the host, pathogen survival, and immune evasion. The dense cell envelope glycocalyx contains distinctive monosaccharides that are stitched together into higher order glycans to yield exclusively bacterial structures that are critical for strain fitness and pathogenesis. However, the systematic study and inhibition of bacterial glycosylation enzymes remains challenging. Bacteria produce glycans containing rare sugars refractory to traditional glycan analysis, complicating the study of bacterial glycans and the identification of their biosynthesis machinery. To ease the study of bacterial glycans in the absence of detailed structural information, we used metabolic glycan labeling to detect changes in glycan biosynthesis. Here, we screened wild-type versus mutant strains of the gastric pathogen , ultimately permitting the identification of genes involved in glycoprotein and lipopolysaccharide biosynthesis. Our findings provide the first evidence that protein glycosylation proceeds via a lipid carrier-mediated pathway that overlaps with lipopolysaccharide biosynthesis. Protein glycosylation mutants displayed fitness defects consistent with those induced by small molecule glycosylation inhibitors. Broadly, our results suggest a facile approach to screen for bacterial glycosylation genes and gain insight into their biosynthesis and functional importance, even in the absence of glycan structural information.
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http://dx.doi.org/10.1021/acsinfecdis.0c00612DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7808405PMC
December 2020

Metabolic inhibitors of bacterial glycan biosynthesis.

Chem Sci 2020 Jan 8;11(7):1761-1774. Epub 2020 Jan 8.

Department of Chemistry & Biochemistry, Bowdoin College 6600 College Station Brunswick ME 04011 USA

The bacterial cell wall is a quintessential drug target due to its critical role in colonization of the host, pathogen survival, and immune evasion. The dense cell wall glycocalyx contains distinctive monosaccharides that are absent from human cells, and proper assembly of monosaccharides into higher-order glycans is critical for bacterial fitness and pathogenesis. However, the systematic study and inhibition of bacterial glycosylation enzymes remains challenging. Bacteria produce glycans containing rare deoxy amino sugars refractory to traditional glycan analysis, complicating the study of bacterial glycans and the creation of glycosylation inhibitors. To ease the study of bacterial glycan function in the absence of detailed structural or enzyme information, we crafted metabolic inhibitors based on rare bacterial monosaccharide scaffolds. Metabolic inhibitors were assessed for their ability to interfere with glycan biosynthesis and fitness in pathogenic and symbiotic bacterial species. Three metabolic inhibitors led to dramatic structural and functional defects in . Strikingly, these inhibitors acted in a bacteria-selective manner. These metabolic inhibitors will provide a platform for systematic study of bacterial glycosylation enzymes not currently possible with existing tools. Moreover, their selectivity will provide a pathway for the development of novel, narrow-spectrum antibiotics to treat infectious disease. Our inhibition approach is general and will expedite the identification of bacterial glycan biosynthesis inhibitors in a range of systems, expanding the glycochemistry toolkit.
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http://dx.doi.org/10.1039/c9sc05955eDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8148367PMC
January 2020

Sugar-Modified Analogs of Auranofin Are Potent Inhibitors of the Gastric Pathogen .

ACS Infect Dis 2019 10 9;5(10):1682-1687. Epub 2019 Sep 9.

Department of Chemistry & Biochemistry , Bowdoin College , 6600 College Station , Brunswick , Maine 04011 , United States.

() infection poses a worldwide public health crisis, as chronic infection is rampant and can lead to gastric ulcers, gastritis, and gastric cancer. Unfortunately, frontline therapies cause harmful side effects and are often ineffective due to antibiotic resistance. The FDA-approved drug auranofin is a gold complex with a Au(I) core coordinated with triethylphosphine and peracetylated thioglucose as the ligands. Auranofin is used for the treatment of rheumatoid arthritis and also displays potent activity against . One of auranofin's modes of action involves cell death by disrupting cellular thiol-redox balance maintained by thioredoxin reductase (TrxR), but this disruption leads to unwanted side effects due to mammalian cell toxicity. Here, we developed and tested sugar-modified analogs of auranofin as potential antibiotics against , with the rationale that modulating the sugar moiety would bias uptake by targeting bacterial cells and mitigating mammalian cell toxicity. Sugar-modified auranofin analogs displayed micromolar minimum inhibitory concentrations against , maintained nanomolar inhibitory activity against the target enzyme TrxR, and caused reduced toxicity to mammalian cells. Taken together, our results suggest that structurally modifying the sugar component of auranofin has the potential to yield superior antibiotics for the treatment of infection. Broadly, glyco-tailoring is an attractive approach for repurposing approved drugs.
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http://dx.doi.org/10.1021/acsinfecdis.9b00251DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7123778PMC
October 2019

Design of a drug discovery course for non-science majors.

Authors:
Danielle H Dube

Biochem Mol Biol Educ 2018 07 12;46(4):327-335. Epub 2018 Mar 12.

Department of Chemistry and Biochemistry, Bowdoin College, 6600 College Station, Brunswick, Maine 04011.

"Drug Discovery" is a 13-week lecture and laboratory-based course that was developed to introduce non-science majors to foundational chemistry and biochemistry concepts as they relate to the unifying theme of drug discovery. The first part of this course strives to build students' understanding of molecules, their properties, the differences that enable them to be separated from one another, and their abilities to bind to biological receptors and elicit physiological effects. After building students' molecular worldview, the course then focuses on four classes of drugs: antimicrobials, drugs that affect the mind, steroid-based drugs, and anti-cancer drugs. During each of these modules, an emphasis is placed on how understanding the basis of disease and molecular-level interactions empowers us to identify novel medicinal compounds. Periodic in class discussions based on articles pertinent to class topics ranging from the spread of antibiotic resistance, to the molecular basis of addiction, to rational drug design, are held to enable students to relate course material to pressing problems of national and daily concern. In addition to class time, weekly inquiry-based laboratories allow students to critically analyze data related to course concepts, and later in the semester give students an opportunity to design and implement their own experiments to screen for antimicrobial activity. This course provides students with an understanding of the importance of chemistry and biochemistry to human health while emphasizing the process, strategies, and challenges related to drug discovery. © 2018 by The International Union of Biochemistry and Molecular Biology, 46:327-335, 2018.
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http://dx.doi.org/10.1002/bmb.21121DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6105404PMC
July 2018

Development of Rare Bacterial Monosaccharide Analogs for Metabolic Glycan Labeling in Pathogenic Bacteria.

ACS Chem Biol 2016 12 28;11(12):3365-3373. Epub 2016 Oct 28.

Department of Chemistry & Biochemistry, Bowdoin College , 6600 College Station, Brunswick, Maine 04011, United States.

Bacterial glycans contain rare, exclusively bacterial monosaccharides that are frequently linked to pathogenesis and essentially absent from human cells. Therefore, bacterial glycans are intriguing molecular targets. However, systematic discovery of bacterial glycoproteins is hampered by the presence of rare deoxy amino sugars, which are refractory to traditional glycan-binding reagents. Thus, the development of chemical tools that label bacterial glycans is a crucial step toward discovering and targeting these biomolecules. Here, we explore the extent to which metabolic glycan labeling facilitates the studying and targeting of glycoproteins in a range of pathogenic and symbiotic bacterial strains. We began with an azide-containing analog of the naturally abundant monosaccharide N-acetylglucosamine and discovered that it is not broadly incorporated into bacterial glycans, thus revealing a need for additional azidosugar substrates to broaden the utility of metabolic glycan labeling in bacteria. Therefore, we designed and synthesized analogs of the rare deoxy amino d-sugars N-acetylfucosamine, bacillosamine, and 2,4-diacetamido-2,4,6-trideoxygalactose and established that these analogs are differentially incorporated into glycan-containing structures in a range of pathogenic and symbiotic bacterial species. Further application of these analogs will refine our knowledge of the glycan repertoire in diverse bacteria and may find utility in treating a variety of infectious diseases with selectivity.
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http://dx.doi.org/10.1021/acschembio.6b00790DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5161589PMC
December 2016

A semester-long project-oriented biochemistry laboratory based on Helicobacter pylori urease.

Biochem Mol Biol Educ 2015 Sep-Oct;43(5):333-40. Epub 2015 Jul 14.

Department of Chemistry and Biochemistry, Bowdoin College, 6600 College Station, Brunswick, Maine, 04011.

Here we present the development of a 13 week project-oriented biochemistry laboratory designed to introduce students to foundational biochemical techniques and then enable students to perform original research projects once they have mastered these techniques. In particular, we describe a semester-long laboratory that focuses on a biomedically relevant enzyme--Helicobacter pylori (Hp) urease--the activity of which is absolutely required for the gastric pathogen Hp to colonize the human stomach. Over the course of the semester, students undertake a biochemical purification of Hp urease, assess the success of their purification, and investigate the activity of their purified enzyme. In the final weeks of the semester, students design and implement their own experiments to study Hp urease. This laboratory provides students with an understanding of the importance of biochemistry in human health while empowering them to engage in an active area of research.
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http://dx.doi.org/10.1002/bmb.20884DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4573817PMC
July 2016

Glycans in pathogenic bacteria--potential for targeted covalent therapeutics and imaging agents.

Chem Commun (Camb) 2014 May;50(36):4659-73

Bowdoin College, Department of Chemistry & Biochemistry, Brunswick, Maine, USA.

A substantial obstacle to the existing treatment of bacterial diseases is the lack of specific probes that can be used to diagnose and treat pathogenic bacteria in a selective manner while leaving the microbiome largely intact. To tackle this problem, there is an urgent need to develop pathogen-specific therapeutics and diagnostics. Here, we describe recent evidence that indicates distinctive glycans found exclusively on pathogenic bacteria could form the basis of targeted therapeutic and diagnostic strategies. In particular, we highlight the use of metabolic oligosaccharide engineering to covalently deliver therapeutics and imaging agents to bacterial glycans.
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http://dx.doi.org/10.1039/c4cc00660gDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4049282PMC
May 2014

Targeted identification of glycosylated proteins in the gastric pathogen Helicobacter pylori (Hp).

Mol Cell Proteomics 2013 Sep 10;12(9):2568-86. Epub 2013 Jun 10.

Department of Chemistry and Biochemistry, Bowdoin College, 6600 College Station, Brunswick, Maine 04011, USA.

Virulence of the gastric pathogen Helicobacter pylori (Hp) is directly linked to the pathogen's ability to glycosylate proteins; for example, Hp flagellin proteins are heavily glycosylated with the unusual nine-carbon sugar pseudaminic acid, and this modification is absolutely essential for Hp to synthesize functional flagella and colonize the host's stomach. Although Hp's glycans are linked to pathogenesis, Hp's glycome remains poorly understood; only the two flagellin glycoproteins have been firmly characterized in Hp. Evidence from our laboratory suggests that Hp synthesizes a large number of as-yet unidentified glycoproteins. Here we set out to discover Hp's glycoproteins by coupling glycan metabolic labeling with mass spectrometry analysis. An assessment of the subcellular distribution of azide-labeled proteins by Western blot analysis indicated that glycoproteins are present throughout Hp and may therefore serve diverse functions. To identify these species, Hp's azide-labeled glycoproteins were tagged via Staudinger ligation, enriched by tandem affinity chromatography, and analyzed by multidimensional protein identification technology. Direct comparison of enriched azide-labeled glycoproteins with a mock-enriched control by both SDS-PAGE and mass spectrometry-based analyses confirmed the selective enrichment of azide-labeled glycoproteins. We identified 125 candidate glycoproteins with diverse biological functions, including those linked with pathogenesis. Mass spectrometry analyses of enriched azide-labeled glycoproteins before and after cleavage of O-linked glycans revealed the presence of Staudinger ligation-glycan adducts in samples only after beta-elimination, confirming the synthesis of O-linked glycoproteins in Hp. Finally, the secreted colonization factors urease alpha and urease beta were biochemically validated as glycosylated proteins via Western blot analysis as well as by mass spectrometry analysis of cleaved glycan products. These data set the stage for the development of glycosylation-based therapeutic strategies, such as new vaccines based on natively glycosylated Hp proteins, to eradicate Hp infection. Broadly, this report validates metabolic labeling as an effective and efficient approach for the identification of bacterial glycoproteins.
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http://dx.doi.org/10.1074/mcp.M113.029561DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3769331PMC
September 2013

Recruiting the host's immune system to target Helicobacter pylori's surface glycans.

Chembiochem 2013 Apr 19;14(6):721-6. Epub 2013 Mar 19.

Department of Chemistry & Biochemistry, Bowdoin College, 6600 College Station, Brunswick, ME 04011, USA.

Due to the increased prevalence of bacterial strains that are resistant to existing antibiotics, there is an urgent need for new antibacterial strategies. Bacterial glycans are an attractive target for new treatments, as they are frequently linked to pathogenesis and contain distinctive structures that are absent in humans. We set out to develop a novel targeting strategy based on surface glycans present on the gastric pathogen Helicobacter pylori (Hp). In this study, metabolic labeling of bacterial glycans with an azide-containing sugar allowed selective delivery of immune stimulants to azide-covered Hp. We established that Hp's surface glycans are labeled by treatment with the metabolic substrate peracetylated N-azidoacetylglucosamine (Ac4 GlcNAz). By contrast, mammalian cells treated with Ac4 GlcNAz exhibited no incorporation of the chemical label within extracellular glycans. We further demonstrated that the Staudinger ligation between azides and phosphines proceeds under acidic conditions with only a small loss of efficiency. We then targeted azide-covered Hp with phosphines conjugated to the immune stimulant 2,4-dinitrophenyl (DNP), a compound capable of directing a host immune response against these cells. Finally, we report that immune effector cells catalyze selective damage in vitro to DNP-covered Hp in the presence of anti-DNP antibodies. The technology reported herein represents a novel strategy to target Hp based on its glycans.
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http://dx.doi.org/10.1002/cbic.201300006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3786562PMC
April 2013

Deciphering the bacterial glycocode: recent advances in bacterial glycoproteomics.

Curr Opin Chem Biol 2013 Feb 29;17(1):41-8. Epub 2012 Dec 29.

Department of Chemistry and Biochemistry, Bowdoin College, 6600 College Station, Brunswick, ME 04011, USA.

Bacterial glycoproteins represent an attractive target for new antibacterial treatments, as they are frequently linked to pathogenesis and contain distinctive glycans that are absent in humans. Despite their potential therapeutic importance, many bacterial glycoproteins remain uncharacterized. This review focuses on recent advances in deciphering the bacterial glycocode, including metabolic glycan labeling to discover and characterize bacterial glycoproteins, lectin-based microarrays to monitor bacterial glycoprotein dynamics, crosslinking sugars to assess the roles of bacterial glycoproteins, and harnessing bacterial glycosylation systems for the efficient production of industrially important glycoproteins.
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http://dx.doi.org/10.1016/j.cbpa.2012.12.006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3594442PMC
February 2013

A two-hybrid assay to study protein interactions within the secretory pathway.

PLoS One 2010 Dec 28;5(12):e15648. Epub 2010 Dec 28.

Department of Chemistry and Biochemistry, Bowdoin College, Brunswick, Maine, United States of America.

Interactions of transcriptional activators are difficult to study using transcription-based two-hybrid assays due to potent activation resulting in false positives. Here we report the development of the Golgi two-hybrid (G2H), a method that interrogates protein interactions within the Golgi, where transcriptional activators can be assayed with negligible background. The G2H relies on cell surface glycosylation to report extracellularly on protein-protein interactions occurring within the secretory pathway. In the G2H, protein pairs are fused to modular domains of the reporter glycosyltransferase, Och1p, and proper cell wall formation due to Och1p activity is observed only when a pair of proteins interacts. Cells containing interacting protein pairs are identified by selectable phenotypes associated with Och1p activity and proper cell wall formation: cells that have interacting proteins grow under selective conditions and display weak wheat germ agglutinin (WGA) binding by flow cytometry, whereas cells that lack interacting proteins display stunted growth and strong WGA binding. Using this assay, we detected the interaction between transcription factor MyoD and its binding partner Id2. Interfering mutations along the MyoD:Id2 interaction interface ablated signal in the G2H assay. Furthermore, we used the G2H to detect interactions of the activation domain of Gal4p with a variety of binding partners. Finally, selective conditions were used to enrich for cells encoding interacting partners. The G2H detects protein-protein interactions that cannot be identified via traditional two-hybrid methods and should be broadly useful for probing previously inaccessible subsets of the interactome, including transcriptional activators and proteins that traffic through the secretory pathway.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0015648PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3011011PMC
December 2010

Chemical tools to discover and target bacterial glycoproteins.

Chem Commun (Camb) 2011 Jan 23;47(1):87-101. Epub 2010 Aug 23.

Bowdoin College, Department of Chemistry & Biochemistry, Brunswick, Maine, USA.

Bacterial protein glycosylation is an important post-translational modification that can distinguish pathogenic bacteria from human cells. This review discusses recent findings in the field of bacterial glycobiology, with a particular focus on the unusual structures of bacterial glycans and their link to pathogenesis. We then describe how chemical tools can augment the study of this class of biomolecules, offering the potential to unveil novel pathogen-associated targets. Finally, this article highlights recent advances in targeting bacteria with therapeutics based on their unique glycans.
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http://dx.doi.org/10.1039/c0cc01557aDOI Listing
January 2011

A strategy for the selective imaging of glycans using caged metabolic precursors.

J Am Chem Soc 2010 Jul;132(28):9516-8

Department of Chemistry and Howard Hughes Medical Institute, University of California, Berkeley, California 94720, USA.

Glycans can be imaged by metabolic labeling with azidosugars followed by chemical reaction with imaging probes; however, tissue-specific labeling is difficult to achieve. Here we describe a strategy for the use of a caged metabolic precursor that is activated for cellular metabolism by enzymatic cleavage. An N-azidoacetylmannosamine derivative caged with a peptide substrate for the prostate-specific antigen (PSA) protease was converted to cell-surface azido sialic acids in a PSA-dependent manner. The approach has applications in tissue-selective imaging of glycans for clinical and basic research purposes.
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http://dx.doi.org/10.1021/ja101080yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2907715PMC
July 2010

Metabolic profiling of Helicobacter pylori glycosylation.

Mol Biosyst 2009 Sep 23;5(9):909-12. Epub 2009 Jun 23.

Bowdoin College, Department of Chemistry & Biochemistry, Brunswick, Maine, USA.

Metabolic oligosaccharide engineering was used to profile glycoproteins of the human pathogen Helicobacter pylori.
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http://dx.doi.org/10.1039/b902178gDOI Listing
September 2009

Regulating cell surface glycosylation with a small-molecule switch.

Methods Enzymol 2006 ;415:213-29

Department of Chemistry, Stanford University, CA, USA.

Correct localization of Golgi-resident enzymes is essential for the formation of specific glycan epitopes. In this chapter, we describe a method to control the localization, and thus the activity, of an individual glycosyltransferase by administration of a small molecule. Our method takes advantage of the modularity of most Golgi-resident enzymes, which are composed of localization and catalytic domains. These domains can be physically separated and fused to the small molecule binding proteins FRB and FKBP, which dimerize in the presence of rapamycin. In this way, rapamycin serves as a "switch" for enzyme activity.
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http://dx.doi.org/10.1016/S0076-6879(06)15014-4DOI Listing
February 2007

Probing mucin-type O-linked glycosylation in living animals.

Proc Natl Acad Sci U S A 2006 Mar 20;103(13):4819-24. Epub 2006 Mar 20.

Department of Chemistry, University of California, Berkeley, CA 94720, USA.

Changes in O-linked protein glycosylation are known to correlate with disease states but are difficult to monitor in a physiological setting because of a lack of experimental tools. Here, we report a technique for rapid profiling of O-linked glycoproteins in living animals by metabolic labeling with N-azidoacetylgalactosamine (GalNAz) followed by Staudinger ligation with phosphine probes. After injection of mice with a peracetylated form of GalNAz, azide-labeled glycoproteins were observed in a variety of tissues, including liver, kidney, and heart, in serum, and on isolated splenocytes. B cell glycoproteins were robustly labeled with GalNAz but T cell glycoproteins were not, suggesting fundamental differences in glycosylation machinery or metabolism. Furthermore, GalNAz-labeled B cells could be selectively targeted with a phosphine probe by Staudinger ligation within the living animal. Metabolic labeling with GalNAz followed by Staudinger ligation provides a means for proteomic analysis of this posttranslational modification and for identifying O-linked glycoprotein fingerprints associated with disease.
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http://dx.doi.org/10.1073/pnas.0506855103DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1405625PMC
March 2006

Glycans in cancer and inflammation--potential for therapeutics and diagnostics.

Nat Rev Drug Discov 2005 Jun;4(6):477-88

Department of Chemistry, University of California, Berkeley, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.

Changes in glycosylation are often a hallmark of disease states. For example, cancer cells frequently display glycans at different levels or with fundamentally different structures than those observed on normal cells. This phenomenon was first described in the early 1970s, but the molecular details underlying such transformations were poorly understood. In the past decade advances in genomics, proteomics and mass spectrometry have enabled the association of specific glycan structures with disease states. In some cases, the functional significance of disease-associated changes in glycosylation has been revealed. This review highlights changes in glycosylation associated with cancer and chronic inflammation and new therapeutic and diagnostic strategies that are based on the underlying glycobiology.
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http://dx.doi.org/10.1038/nrd1751DOI Listing
June 2005

Chemical remodelling of cell surfaces in living animals.

Nature 2004 Aug;430(7002):873-7

Department of Chemistry, University of California, Berkeley, California 94720, USA.

Cell surfaces are endowed with biological functionality designed to mediate extracellular communication. The cell-surface repertoire can be expanded to include abiotic functionality through the biosynthetic introduction of unnatural sugars into cellular glycans, a process termed metabolic oligosaccharide engineering. This technique has been exploited in fundamental studies of glycan-dependent cell-cell and virus-cell interactions and also provides an avenue for the chemical remodelling of living cells. Unique chemical functional groups can be delivered to cell-surface glycans by metabolism of the corresponding unnatural precursor sugars. These functional groups can then undergo covalent reaction with exogenous agents bearing complementary functionality. The exquisite chemical selectivity required of this process is supplied by the Staudinger ligation of azides and phosphines, a reaction that has been performed on cultured cells without detriment to their physiology. Here we demonstrate that the Staudinger ligation can be executed in living animals, enabling the chemical modification of cells within their native environment. The ability to tag cell-surface glycans in vivo may enable therapeutic targeting and non-invasive imaging of changes in glycosylation during disease progression.
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http://dx.doi.org/10.1038/nature02791DOI Listing
August 2004

Metabolic oligosaccharide engineering as a tool for glycobiology.

Curr Opin Chem Biol 2003 Oct;7(5):616-25

Department of Chemistry, Howard Hughes Medical Institute, University of California, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.

Oligosaccharides transact information exchange at the cell surface and modulate the activities and distribution of proteins within cells. Recently, the ability to modify monosaccharide structures within cellular glycans through metabolic processes has offered a new avenue for biological studies. The technique of metabolic oligosaccharide engineering has been used to disrupt glycan biosynthesis, chemically modify cell surfaces, probe metabolic flux inside cells, and to identify specific glycoprotein subtypes from the proteome.
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http://dx.doi.org/10.1016/j.cbpa.2003.08.006DOI Listing
October 2003

Constructing azide-labeled cell surfaces using polysaccharide biosynthetic pathways.

Methods Enzymol 2003 ;362:249-72

Department of Chemistry, University of California, Berkeley, California 94720, USA.

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http://dx.doi.org/10.1016/S0076-6879(03)01018-8DOI Listing
November 2003
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