2YL3

CYTOCHROME C PRIME FROM ALCALIGENES XYLOSOXIDANS: CARBON MONOOXIDE BOUND L16G VARIANT AT 1.04 A RESOLUTION - RESTRAINT REFINED

2YL3 の概要

• エントリーDOI: 10.2210/pdb2yl3/pdb
• 関連するPDBエントリー: 1CGN 1CGO 1E83 1E84 1E85 1E86 2XL6 2XL8 2XLD 2XLE 2XLH 2XLM 2XLO 2XLV 2XLW 2XM0 2XM4 2YKZ 2YL0 2YL1 2YL7
• 分子名称: CYTOCHROME C', CARBON MONOXIDE, HEME C, ... (5 entities in total)
• 機能のキーワード: electron transport, haemoprotein, 4-helix bundle
• 由来する生物種: ACHROMOBACTER XYLOSOXIDANS
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 14317.91

構造登録者

Antonyuk, S.V.,Rustage, N.,Eady, R.R.,Hasnain, S.S. (登録日: 2011-05-31, 公開日: 2011-10-05, 最終更新日: 2024-11-13)

主引用文献

Antonyuk, S.V.,Rustage, N.,Petersen, C.A.,Arnst, J.L.,Heyes, D.J.,Sharma, R.,Berry, N.G.,Scrutton, N.S.,Eady, R.R.,Andrew, C.R.,Hasnain, S.S.
Carbon Monoxide Poisoning is Prevented by the Energy Costs of Conformational Changes in Gas- Binding Haemproteins.
Proc.Natl.Acad.Sci.USA, 108:15780-, 2011

PubMed Abstract: Carbon monoxide (CO) is a product of haem metabolism and organisms must evolve strategies to prevent endogenous CO poisoning of haemoproteins. We show that energy costs associated with conformational changes play a key role in preventing irreversible CO binding. AxCYTcp is a member of a family of haem proteins that form stable 5c-NO and 6c-CO complexes but do not form O(2) complexes. Structure of the AxCYTcp-CO complex at 1.25 Å resolution shows that CO binds in two conformations moderated by the extent of displacement of the distal residue Leu16 toward the haem 7-propionate. The presence of two CO conformations is confirmed by cryogenic resonance Raman data. The preferred linear Fe-C-O arrangement (170 ± 8°) is accompanied by a flip of the propionate from the distal to proximal face of the haem. In the second conformation, the Fe-C-O unit is bent (158 ± 8°) with no flip of propionate. The energetic cost of the CO-induced Leu-propionate movements is reflected in a 600 mV (57.9 kJ mol(-1)) decrease in haem potential, a value in good agreement with density functional theory calculations. Substitution of Leu by Ala or Gly (structures determined at 1.03 and 1.04 Å resolutions) resulted in a haem site that binds CO in the linear mode only and where no significant change in redox potential is observed. Remarkably, these variants were isolated as ferrous 6c-CO complexes, attributable to the observed eight orders of magnitude increase in affinity for CO, including an approximately 10,000-fold decrease in the rate of dissociation. These new findings have wide implications for preventing CO poisoning of gas-binding haem proteins.

PubMed: 21900609
DOI: 10.1073/PNAS.1109051108

実験手法

X-RAY DIFFRACTION (1.04 Å)