2THI

THIAMINASE I FROM BACILLUS THIAMINOLYTICUS

2THI の概要

• エントリーDOI: 10.2210/pdb2thi/pdb
• 分子名称: THIAMINASE I, SULFATE ION (3 entities in total)
• 機能のキーワード: thiamine degradation, transferase
• 由来する生物種: Paenibacillus thiaminolyticus
• 細胞内の位置: Secreted: P45741
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 84424.98

構造登録者

Campobasso, N.,Begley, T.P.,Ealick, S.E. (登録日: 1998-09-17, 公開日: 1999-10-07, 最終更新日: 2023-12-27)

主引用文献

Campobasso, N.,Costello, C.A.,Kinsland, C.,Begley, T.P.,Ealick, S.E.
Crystal structure of thiaminase-I from Bacillus thiaminolyticus at 2.0 A resolution.
Biochemistry, 37:15981-15989, 1998

PubMed Abstract: Thiaminase-I catalyzes the replacement of the thiazole moiety of thiamin with a wide variety of nucleophiles, such as pyridine, aniline, catechols, quinoline, and cysteine. The crystal structure of the enzyme from Bacillus thiaminolyticus was determined at 2.5 A resolution by multiple isomorphous replacement and refined to an R factor of 0.195 (Rfree = 0.272). Two other structures, one native and one containing a covalently bound inhibitor, were determined at 2.0 A resolution by molecular replacement from a second crystal form and were refined to R factors of 0.205 and 0.217 (Rfree = 0.255 and 0.263), respectively. The overall structure contains two alpha/beta-type domains separated by a large cleft. At the base of the cleft lies Cys113, previously identified as a key active site nucleophile. The structure with a covalently bound thiamin analogue, which functions as a mechanism-based inactivating agent, confirms the location of the active site. Glu241 appears to function as an active site base to increase the nucleophilicity of Cys113. The mutant Glu241Gln was made and shows no activity. Thiaminase-I shows no sequence identity to other proteins in the sequence databases, but the three-dimensional structure shows very high structural homology to the periplasmic binding proteins and the transferrins.

PubMed: 9843405
DOI: 10.1021/bi981673l

実験手法

X-RAY DIFFRACTION (2.5 Å)