4HCW

Structure of a eukaryotic thiaminase-I

4HCW の概要

• エントリーDOI: 10.2210/pdb4hcw/pdb
• 関連するPDBエントリー: 4HCY
• 分子名称: thiaminase-I (1 entity in total)
• 機能のキーワード: thiamine pyridinylase, transferase
• 由来する生物種: Naegleria gruberi (Amoeba)
• タンパク質・核酸の鎖数: 6
• 化学式量合計: 235710.65

構造登録者

Kreinbring, C.A.,Hubbard, P.A.,Petsko, G.A.,Ringe, D. (登録日: 2012-10-01, 公開日: 2013-10-02, 最終更新日: 2024-02-28)

主引用文献

Kreinbring, C.A.,Remillard, S.P.,Hubbard, P.,Brodkin, H.R.,Leeper, F.J.,Hawksley, D.,Lai, E.Y.,Fulton, C.,Petsko, G.A.,Ringe, D.
Structure of a eukaryotic thiaminase I.
Proc.Natl.Acad.Sci.USA, 111:137-142, 2014

PubMed Abstract: Thiaminases, enzymes that cleave vitamin B1, are sporadically distributed among prokaryotes and eukaryotes. Thiaminase I enzymes catalyze the elimination of the thiazole ring moiety from thiamin through substitution of the methylene group with a nitrogenous base or sulfhydryl compound. In eukaryotic organisms, these enzymes are reported to have much higher molecular weights than their bacterial counterparts. A thiaminase I of the single-celled amoeboflagellate Naegleria gruberi is the only eukaryotic thiaminase I to have been cloned, sequenced, and expressed. Here, we present the crystal structure of N. gruberi thiaminase I to a resolution of 2.8 Å, solved by isomorphous replacement and pseudo-two-wavelength multiwavelength anomalous diffraction and refined to an R factor of 0.231 (Rfree, 0.265). This structure was used to solve the structure of the enzyme in complex with 3-deazathiamin, a noncleavable thiamin analog and enzyme inhibitor (2.7 Å; R, 0.233; Rfree, 0.267). These structures define the mode of thiamin binding to this class of thiaminases and indicate the involvement of Asp272 as the catalytic base. This enzyme is able to use thiamin as a substrate and is active with amines such as aniline and veratrylamine as well as sulfhydryl compounds such as l-cysteine and β-mercaptoethanol as cosubstrates. Despite significant differences in polypeptide sequence and length, we have shown that the N. gruberi thiaminase I is homologous in structure and activity to a previously characterized bacterial thiaminase I.

PubMed: 24351929
DOI: 10.1073/pnas.1315882110

実験手法

X-RAY DIFFRACTION (2.705 Å)