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We recently reported statistical analysis of structural data on glycosidic linkages. Here we extend this analysis to the glycan-protein linkage, and the peptide primary, secondary, and tertiary structures around N-glycosylation sites. We surveyed 506 glycoproteins in the Protein Data Bank crystallographic database, giving 2592 glycosylation sequons (1683(More)
Tyrosinase is the key enzyme in melanin biosynthesis, catalyzing multiple steps in this pathway. The mature glycoprotein is transported from the Golgi to the melanosome where melanin biosynthesis occurs. In this study, we have investigated the effects of inhibitors of N-glycan processing on the synthesis, transport, and catalytic activity of tyrosinase.(More)
Calnexin is a membrane protein of the endoplasmic reticulum that associates transiently with newly synthesized N-linked glycoproteins in vivo. Using defined components, the binding of ribonuclease B (RNase B) Man7-Man9 glycoforms to the luminal domain of calnexin was observed in vitro only if RNase B was monoglucosylated. Binding was independent of the(More)
Tyrosinase is a copper-containing enzyme that regulates melanin biosynthesis in mammals. Mutations at a single N-glycosylation sequon of tyrosinase have been reported to be responsible for oculocutaneous albinism type IA in humans, characterized by inactive tyrosinase and the total absence of pigmentation. To probe the role that each N-glycosylation site(More)
Ovarian cancer is the fourth most common cancer in women in the Western world. In a pilot scale study, we highlight changes in the total serum glycome of patients with advanced ovarian cancer that might shed insight into disease pathogenesis. These changes include increases in levels of core fucosylated, agalactosyl biantennary glycans (FA2) and sialyl(More)
Tyrosinase is a type I membrane protein regulating the pigmentation process in humans. Mutations of the human tyrosinase gene cause the tyrosinase negative type I oculocutaneous albinism (OCAI). Some OCAI mutations were shown to delete the transmembrane domain or to affect its hydrophobic properties, resulting in soluble tyrosinase mutants that are retained(More)
We have generated a database of 639 glycosidic linkage structures by an exhaustive survey of the available crystallographic data for isolated oligosaccharides, glycoproteins, and glycan-binding proteins. For isolated oligosaccharides there is relatively little crystallographic data available. A much larger number of glycoprotein and glycan-binding protein(More)
Glucosylated oligomannose N-linked oligosaccharides (Glc(x)Man9GlcNAc2 where x = 1-3) are not normally found on mature glycoproteins but are involved in the early stages of glycoprotein biosynthesis and folding as (i) recognition elements during protein N-glycosylation and chaperone recognition and (ii) substrates in the initial steps of N-glycan(More)
Investigation of the entry pathways of hepatitis B virus (HBV), a member of the family Hepadnaviridae, has been hampered by the lack of versatile in vitro infectivity models. Most concepts of hepadnaviral infection come from the more robust duck HBV system; however, whether the two viruses use the same mechanisms to invade target cells is still a matter of(More)