2wcu
From Proteopedia
CRYSTAL STRUCTURE OF MAMMALIAN FUCU
Structural highlights
Function[FUCM_MOUSE] Involved in the interconversion between alpha- and beta-L-fucoses. L-Fucose (6-deoxy-L-galactose) exists as alpha-L-fucose (29.5%) and beta-L-fucose (70.5%), the beta-form is metabolized through the salvage pathway. GDP-L-fucose formed either by the de novo or salvage pathways is transported into the endoplasmic reticulum, where it serves as a substrate for N- and O-glycosylations by fucosyltransferases. Fucosylated structures expressed on cell surfaces or secreted in biological fluids are believed to play a critical role in cell-cell adhesion and recognition processes.[1] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedEscherichia coli FucU (Fucose Unknown) is a dual fucose mutarotase and ribose pyranase, which shares 44% sequence identity with its human counterpart. Herein, we report the structures of E. coli FucU and mouse FucU bound to L-fucose and delineate the catalytic mechanisms underlying the interconversion between stereoisomers of fucose and ribose. E. coli FucU forms a decameric toroid with each active site formed by two adjacent subunits. While one subunit provides most of the fucose-interacting residues including a catalytic tyrosine residue, the other subunit provides a catalytic His-Asp dyad. This active-site feature is critical not only for the mutarotase activity toward L-fucose but also for the pyranase activity toward D-ribose. Structural and biochemical analyses pointed that mouse FucU assembles into four different oligomeric forms, among which the smallest homodimeric form is most abundant and would be the predominant species under physiological conditions. This homodimer has two fucose-binding sites that are devoid of the His-Asp dyad and catalytically inactive, indicating that the mutarotase and the pyranase activities appear dispensable in vertebrates. The defective assembly of the mouse FucU homodimer into the decameric form is due to an insertion of two residues at the N-terminal extreme, which is a common aspect of all the known vertebrate FucU proteins. Therefore, vertebrate FucU appears to serve for as yet unknown function through the quaternary structural alteration. Crystal structures and enzyme mechanisms of a dual fucose mutarotase/ribose pyranase.,Lee KH, Ryu KS, Kim MS, Suh HY, Ku B, Song YL, Ko S, Lee W, Oh BH J Mol Biol. 2009 Aug 7;391(1):178-91. Epub 2009 Jun 11. PMID:19524593[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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Categories: Lk3 transgenic mice | Kim, M S | Ku, B | Lee, K H | Oh, B H | Song, Y L | Suh, H Y | Fucose | Fucu | Isomerase | Mutarotase | Pyranase | Ribose
