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E. Li

Bio: E. Li is an academic researcher from Washington University in St. Louis. The author has contributed to research in topics: Oligosaccharide & Chinese hamster ovary cell. The author has an hindex of 5, co-authored 5 publications receiving 975 citations.

Papers
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Journal ArticleDOI
TL;DR: The synthesis of the complex-type oligosaccharide unit of the vesicular stomatitis virus G protein is initiated by the en bloc transfer of a high molecular weight oligosACcharide from a lipid carrier to the nascent polypeptide.

398 citations

Journal ArticleDOI
TL;DR: To elucidate the sequence of processing, pulse-chase experiments were performed with virus-infected Chinese hamster ovary cells using labeled mannose, glucosamine, and galactose and demonstrated that processing is initiated by the rapid removal of 2 of the 3 glucose residues of the precursor oligosaccharide.

331 citations

Journal ArticleDOI
TL;DR: An asparagine-linked oligosaccharide with an unusual structure has been isolated from Pronase digests of Chinese hamster ovary cell glycoproteins using gel filtration, ion exchange chromatography, and affinity chromatography on lectin-Sepharose columns.

94 citations

Book ChapterDOI
01 Jan 1979
TL;DR: A study of oligosaccharide processing in vesicular stomatitis virus-infected Chinese hamster ovary cells and how it is processed by the removal of glucose and mannose residues is presented.
Abstract: Publisher Summary This chapter focuses on oligosaccharide processing during glycoprotein biosynthesis. The oligosaccharides share a common core structure but differ in their outer branches. Biosynthesis of asparagine-linked oligosaccharide units is initiated by the “en bloc” transfer of a preformed oligosaccharide from an oligosaccharide pyrophosphoryldolichol intermediate to an asparagine residue of the nascent polypeptide chain. It has been demonstrated that the synthesis of complex-type oligosaccharides involves the transfer of a glucose-containing high mannose-type oligosaccharide from the lipid carrier to the nascent polypeptide and that following transfer to the protein the oligosaccharide is processed by the removal of glucose and mannose residues. This chapter presents a study of oligosaccharide processing in vesicular stomatitis virus-infected Chinese hamster ovary cells. This virus contains a single glycoprotein—termed G—which has two complex-type oligosaccharides. VSV-infected Chinese hamster ovary cells synthesize a lipid-linked oligosaccharide. This oligosaccharide has three branches, one of which contains three glucose residues. The glucose residues probably function as a signal for transfer of the oligosaccharide to the nascent protein.

34 citations


Cited by
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Journal ArticleDOI
TL;DR: It is time for the diverse functional roles of glycans to be fully incorporated into the mainstream of biological sciences, as they are no different from other major macromolecular building blocks of life, simply more rapidly evolving and complex.
Abstract: Simple and complex carbohydrates (glycans) have long been known to play major metabolic, structural and physical roles in biological systems. Targeted microbial binding to host glycans has also been studied for decades. But such biological roles can only explain some of the remarkable complexity and organismal diversity of glycans in nature. Reviewing the subject about two decades ago, one could find very few clear-cut instances of glycan-recognition-specific biological roles of glycans that were of intrinsic value to the organism expressing them. In striking contrast there is now a profusion of examples, such that this updated review cannot be comprehensive. Instead, a historical overview is presented, broad principles outlined and a few examples cited, representing diverse types of roles, mediated by various glycan classes, in different evolutionary lineages. What remains unchanged is the fact that while all theories regarding biological roles of glycans are supported by compelling evidence, exceptions to each can be found. In retrospect, this is not surprising. Complex and diverse glycans appear to be ubiquitous to all cells in nature, and essential to all life forms. Thus, >3 billion years of evolution consistently generated organisms that use these molecules for many key biological roles, even while sometimes coopting them for minor functions. In this respect, glycans are no different from other major macromolecular building blocks of life (nucleic acids, proteins and lipids), simply more rapidly evolving and complex. It is time for the diverse functional roles of glycans to be fully incorporated into the mainstream of biological sciences.

1,588 citations

Journal ArticleDOI
TL;DR: A number of inhibitors have been identified that interfere with glycoprotein biosynthesis, processing, or transport, such as tunicamycin, tridecaptin, and flavomycin this paper.
Abstract: A number of glycoproteins have oligosaccharides linked to protein in a GlcNAc----asparagine bond. These oligosaccharides may be either of the complex, the high-mannose or the hybrid structure. Each type of oligosaccharides is initially biosynthesized via lipid-linked oligosaccharides to form a Glc3Man9GlcNAc2-pyrophosphoryl-dolichol and transfer of this oligosaccharide to protein. The oligosaccharide portion is then processed, first of all by removal of all three glucose residues to give a Man9GlcNAc2-protein. This structure may be the immediate precursor to the high-mannose structure or it may be further processed by the removal of a number of mannose residues. Initially four alpha 1,2-linked mannoses are removed to give a Man5 - GlcNAc2 -protein which is then lengthened by the addition of a GlcNAc residue. This new structure, the GlcNAc- Man5 - GlcNAc2 -protein, is the substrate for mannosidase II which removes the alpha 1,3- and alpha 1,6-linked mannoses . Then the other sugars, GlcNAc, galactose, and sialic acid, are added sequentially to give the complex types of glycoproteins. A number of inhibitors have been identified that interfere with glycoprotein biosynthesis, processing, or transport. Some of these inhibitors have been valuable tools to study the reaction pathways while others have been extremely useful for examining the role of carbohydrate in glycoprotein function. For example, tunicamycin and its analogs prevent protein glycosylation by inhibiting the first step in the lipid-linked pathway, i.e., the formation of Glc NAc-pyrophosphoryl-dolichol. These antibiotics have been widely used in a number of functional studies. Another antibiotic that inhibits the lipid-linked saccharide pathway is amphomycin, which blocks the formation of dolichyl-phosphoryl-mannose. In vitro, this antibiotic gives rise to a Man5GlcNAc2 -pyrophosphoryl-dolichol from GDP-[14C]mannose, indicating that the first five mannose residues come directly from GDP-mannose rather than from dolichyl-phosphoryl-mannose. Other antibodies that have been shown to act at the lipid-level are diumycin , tsushimycin , tridecaptin, and flavomycin. In addition to these types of compounds, a number of sugar analogs such as 2-deoxyglucose, fluoroglucose , glucosamine, etc. have been utilized in some interesting experiments. Several compounds have been shown to inhibit glycoprotein processing. One of these, the alkaloid swainsonine , inhibits mannosidase II that removes alpha-1,3 and alpha-1,6 mannose residues from the GlcNAc- Man5GlcNAc2 -peptide. Thus, in cultured cells or in enveloped viruses, swainsonine causes the formation of a hybrid structure.(ABSTRACT TRUNCATED AT 400 WORDS)

1,067 citations

01 Jan 1987
TL;DR: A number of glycoproteins have oligosaccharides linked to protein in a GlcNAc----asparagine bond that are either of the complex, the high-mannose or the hybrid structure and a number of inhibitors have been identified that interfere with glycoprotein biosynthesis, processing, or transport.

900 citations

Book ChapterDOI
TL;DR: This chapter presents literature data on the high-resolution, 1H-NMR spectroscopy of carbohydrates derived from glycoconjugates and discusses the results for carbohydrates related to the glycoproteins of N-glycosylic type.
Abstract: Publisher Summary This chapter discusses the application of high-resolution, 1H-nuclear magnetic resonance (NMR) spectroscopy to the structural analysis of carbohydrates related to glycoproteins. Glycoproteins are biopolymers consisting of a polypeptide backbone bearing one or more covalently linked carbohydrate chains. The carbohydrate chains of glycoproteins may be classified according to the type of linkage to the polypeptide backbone. N-Glycosylic chains are attached to the amide group of asparagine (Asn), whereas the O-glycosylic chains are linked to the hydroxyl group of amino acid residues such as serine (Ser), threonine (Thr), and hydroxylysine (Hyl). The high-resolution, 1H-NMR spectroscopy technique, in conjunction with methylation analysis, is extremely suitable for the structural studies of N-, as well as on O-, glycosylic glycans. For the interpretation of the 1H-NMR spectrum of a carbohydrate chain in terms of primary structural assignments, the concept of “structural reporter groups” was developed. This means that the chemical shifts of protons resonating at clearly distinguishable positions in the spectrum, together with their coupling constants and the line widths of their signals, bear the information essential to permit the assigning of the primary structure. This chapter presents literature data on the high-resolution, 1H-NMR spectroscopy of carbohydrates derived from glycoconjugates. It also discusses the results for carbohydrates related to the glycoproteins of N-glycosylic type.

797 citations

Journal ArticleDOI
TL;DR: Author(s): Varki, Ajit; Cummings, Richard D; Aebi, Markus; Packer, Nicole H; Seeberger, Peter H; Esko, Jeffrey D; Stanley, Pamela; Hart, Gerald; Darvill, Alan; Kinoshita, Taroh; Prestegard, James J; Schnaar, Ronald L; Freeze, Hudson H; Marth, Jamey D; Bertozzi, Carolyn R.
Abstract: Author(s): Varki, Ajit; Cummings, Richard D; Aebi, Markus; Packer, Nicole H; Seeberger, Peter H; Esko, Jeffrey D; Stanley, Pamela; Hart, Gerald; Darvill, Alan; Kinoshita, Taroh; Prestegard, James J; Schnaar, Ronald L; Freeze, Hudson H; Marth, Jamey D; Bertozzi, Carolyn R; Etzler, Marilynn E; Frank, Martin; Vliegenthart, Johannes Fg; Lutteke, Thomas; Perez, Serge; Bolton, Evan; Rudd, Pauline; Paulson, James; Kanehisa, Minoru; Toukach, Philip; Aoki-Kinoshita, Kiyoko F; Dell, Anne; Narimatsu, Hisashi; York, William; Taniguchi, Naoyuki; Kornfeld, Stuart

735 citations