4ap5
Crystal structure of human POFUT2
Structural highlights
FunctionOFUT2_HUMAN Catalyzes the reaction that attaches fucose through an O-glycosidic linkage to a conserved serine or threonine residue in the consensus sequence C1-X(2,3)-S/T-C2-X(2)-G of thrombospondin type 1 repeats where C1 and C2 are the first and second cysteines, respectively. O-fucosylates members of several protein families including the ADAMTS family, the thrombosporin (TSP) and spondin families. The O-fucosylation of TSRs is also required for restricting epithelial to mesenchymal transition (EMT), maintaining the correct patterning of mesoderm and localization of the definite endoderm (By similarity). Required for the proper secretion of ADAMTS family members such as ADAMSL1 and ADAMST13.[1] [2] [3] [4] [5] Publication Abstract from PubMedProtein O-fucosylation is a post-translational modification found on serine/threonine residues of thrombospondin type 1 repeats (TSR). The fucose transfer is catalysed by the enzyme protein O-fucosyltransferase 2 (POFUT2) and >40 human proteins contain the TSR consensus sequence for POFUT2-dependent fucosylation. To better understand O-fucosylation on TSR, we carried out a structural and functional analysis of human POFUT2 and its TSR substrate. Crystal structures of POFUT2 reveal a variation of the classical GT-B fold and identify sugar donor and TSR acceptor binding sites. Structural findings are correlated with steady-state kinetic measurements of wild-type and mutant POFUT2 and TSR and give insight into the catalytic mechanism and substrate specificity. By using an artificial mini-TSR substrate, we show that specificity is not primarily encoded in the TSR protein sequence but rather in the unusual 3D structure of a small part of the TSR. Our findings uncover that recognition of distinct conserved 3D fold motifs can be used as a mechanism to achieve substrate specificity by enzymes modifying completely folded proteins of very wide sequence diversity and biological function. Structure of human POFUT2: insights into thrombospondin type 1 repeat fold and O-fucosylation.,Chen CI, Keusch JJ, Klein D, Hess D, Hofsteenge J, Gut H EMBO J. 2012 May 15. doi: 10.1038/emboj.2012.143. PMID:22588082[6] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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