5XSA

Crystal Structure of Transketolase in complex with TPP intermediate III from Pichia Stipitis

5XSA の概要

• エントリーDOI: 10.2210/pdb5xsa/pdb
• 分子名称: Transketolase, CALCIUM ION, 2-[3-[(4-azanyl-2-methyl-pyrimidin-5-yl)methyl]-4-methyl-2H-1,3-thiazol-5-yl]ethyl phosphono hydrogen phosphate, ... (4 entities in total)
• 機能のキーワード: transketolase, transferase
• 由来する生物種: Scheffersomyces stipitis CBS 6054 (Yeast)
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 75520.85

構造登録者

Li, T.L.,Hsu, N.S.,Wang, Y.L. (登録日: 2017-06-13, 公開日: 2018-04-25, 最終更新日: 2023-11-22)

主引用文献

Hsu, N.S.,Wang, Y.L.,Lin, K.H.,Chang, C.F.,Lyu, S.Y.,Hsu, L.J.,Liu, Y.C.,Chang, C.Y.,Wu, C.J.,Li, T.L.
The Mesomeric Effect of Thiazolium on non-Kekule Diradicals in Pichia stipitis Transketolase.
Angew. Chem. Int. Ed. Engl., 57:1802-1807, 2018

PubMed Abstract: It is theoretically plausible that thiazolium mesomerizes to congeners other than carbene in a low effective dielectric binding site; especially given the energetics and uneven electronegativity of carbene groups. However, such a phenomenon has never been reported. Nine crystal structures of transketolase obtained from Pichia stipitis (TKps) are reported with subatomic resolution, where thiazolium displays an extraordinary ring-bending effect. The bent thiazolium congeners correlate with non-Kekulé diradicals because there is no gain or loss of electrons. In conjunction with biophysical and biochemical analyses, it is concluded that ring bending is a result of tautomerization of thiazolium with its non- Kekulé diradicals, exclusively in the binding site of TKps. The chemophysical properties of these thiazolium mesomers may account for the great variety of reactivities carried out by thiamine-diphosphate-containing (ThDP) enzymes. The stability of ThDP in living systems can be regulated by the levels of substrates, and hydration and dehydration, as well as diradical-mediated oxidative degradation.

PubMed: 29243887
DOI: 10.1002/anie.201709799

実験手法

X-RAY DIFFRACTION (0.975 Å)