9OMH

WrtF fucosyltransferase - Apo

9OMH の概要

• エントリーDOI: 10.2210/pdb9omh/pdb
• 分子名称: Glycosyltransferase, IMIDAZOLE, CHLORIDE ION, ... (4 entities in total)
• 機能のキーワード: fucose, metal-independent, gt-a, o-antigen, transferase
• 由来する生物種: Rhizobium tropici CIAT 899
• タンパク質・核酸の鎖数: 4
• 化学式量合計: 122401.00

構造登録者

Forrester, T.J.B.,Kimber, M.S. (登録日: 2025-05-14, 公開日: 2025-10-29, 最終更新日: 2025-11-12)

主引用文献

Forrester, T.J.B.,Lin, S.,Lowary, T.L.,Kimber, M.S.
WrtF from Rhizobium tropici CIAT 899 is a GT-A fold fucosyltransferase that binds its donor nonproductively.
Proc.Natl.Acad.Sci.USA, 122:e2512460122-e2512460122, 2025

PubMed Abstract: l-Fucose, a 6-deoxy-monosaccharide, is often incorporated into O-antigens in Rhizobia where it serves as an important marker for host recognition. Here, we biochemically and structurally characterize WrtF, an O-antigen polysaccharide l-fucosyltransferase from the plant endosymbiont CIAT 899. We show that WrtF transfers l-fucose from its donor, guanosine 5'-diphospho-β-l-fucose (GDP-Fuc), to a nonreducing end glucose, creating an α-(1→4) linkage. We determined structures of WrtF at resolutions between 1.45 and 2.3 Å in the apo state, and in complex with GDP, GDP-Fuc, nonacetylated and acetylated trisaccharide acceptors, and with a tetrasaccharide product. WrtF has an N-terminal glycosyltransferase A (GT-A) fold and a unique C-terminal α-helical bundle domain. The structures, combined with activity assays, and sequence analysis show that WrtF is unusual in using neither divalent cations nor basic residues to coordinate and stabilize the donor pyrophosphate. In contrast to almost all previously characterized GT-A glycosyltransferases that use α-linked donors that present the donor monosaccharide axially, GDP-Fuc presents its monosaccharide equatorially. GDP-Fuc binds in a compact conformation with the l-fucose endocyclic oxygen and C6 methyl packed against ribose C5 and C4, respectively. This binding mode paradoxically shields the anomeric carbon from attack; superposition of the donor and acceptor complexes suggests that these substrates would sterically hinder one another and do not appropriately orient to form a Michaelis complex. We therefore propose that the donor l-fucose must reorient in the active site prior to turnover. The preferred occluded donor binding mode may serve to "prescreen" GDP-Fuc from structurally similar candidate donors, while also minimizing counterproductive donor hydrolysis.

PubMed: 41166418
DOI: 10.1073/pnas.2512460122

実験手法

X-RAY DIFFRACTION (1.45 Å)