8Q2E

The 1.68-A X-ray crystal structure of Sporosarcina pasteurii urease inhibited by thiram and bound to dimethylditiocarbamate

8Q2E の概要

• エントリーDOI: 10.2210/pdb8q2e/pdb
• 分子名称: Urease subunit gamma, Urease subunit beta, Urease subunit alpha, ... (9 entities in total)
• 機能のキーワード: urease, nickel, thiram, dimethyldithiocarbamate, enzyme, hydrolase
• 由来する生物種: Sporosarcina pasteurii; 詳細
• タンパク質・核酸の鎖数: 3
• 化学式量合計: 89335.66

構造登録者

Mazzei, L.,Cianci, M.,Ciurli, S. (登録日: 2023-08-02, 公開日: 2023-11-01, 最終更新日: 2023-11-15)

主引用文献

Mazzei, L.,Paul, A.,Cianci, M.,Devodier, M.,Mandelli, D.,Carloni, P.,Ciurli, S.
Kinetic and structural details of urease inactivation by thiuram disulphides.
J.Inorg.Biochem., 250:112398-112398, 2023

PubMed Abstract: This paper reports on the molecular details of the reactivity of urease, a nickel-dependent enzyme that catalyses the last step of organic nitrogen mineralization, with thiuram disulphides, a class of molecules known to inactivate the enzyme with high efficacy but for which the mechanism of action had not been yet established. IC values of tetramethylthiuram disulphide (TMTD or Thiram) and tetraethylthiuram disulphide (TETD or Disulfiram) in the low micromolar range were determined for plant and bacterial ureases. The X-ray crystal structure of Sporosarcina pasteurii urease inactivated by Thiram, determined at 1.68 Å resolution, revealed the presence of a covalent modification of the catalytically essential cysteine residue. This is located on the flexible flap that modulates the size of the active site channel and cavity. Formation of a Cys-S-S-C(S)-N(CH) functionality responsible for enzyme inactivation was observed. Quantum-mechanical calculations carried out to rationalise the large reactivity of the active site cysteine support the view that a conserved histidine residue, adjacent to the cysteine in the active site flap, modulates the charge and electron density along the thiol SH bond by shifting electrons towards the sulphur atom and rendering the thiol proton more reactive. We speculate that this proton could be transferred to the nickel-coordinated urea amide group to yield a molecule of ammonia from the generated C-NH functionality during catalysis.

PubMed: 37879152
DOI: 10.1016/j.jinorgbio.2023.112398

実験手法

X-RAY DIFFRACTION (1.68 Å)