2YCC

OXIDATION STATE-DEPENDENT CONFORMATIONAL CHANGES IN CYTOCHROME C

2YCC の概要

• エントリーDOI: 10.2210/pdb2ycc/pdb
• 関連するPDBエントリー: 1CTY 1CTZ 1YCC
• 分子名称: CYTOCHROME C, SULFATE ION, HEME C, ... (4 entities in total)
• 機能のキーワード: electron transport (heme protein)
• 由来する生物種: Saccharomyces cerevisiae (baker's yeast)
• 細胞内の位置: Mitochondrion intermembrane space: P00044
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 12828.44

構造登録者

Berghuis, A.M.,Brayer, G.D. (登録日: 1991-01-29, 公開日: 1992-07-15, 最終更新日: 2025-03-26)

主引用文献

Berghuis, A.M.,Brayer, G.D.
Oxidation state-dependent conformational changes in cytochrome c.
J.Mol.Biol., 223:959-976, 1992

PubMed Abstract: High-resolution three-dimensional structural analyses of yeast iso-1-cytochrome c have now been completed in both oxidation states using isomorphous crystalline material and similar structure determination methodologies. This approach has allowed a comprehensive comparison to be made between these structures and the elucidation of the subtle conformational changes occurring between oxidation states. The structure solution of reduced yeast iso-1-cytochrome c has been published and the determination of the oxidized protein and a comparison of these structures are reported herein. Our data show that oxidation state-dependent changes are expressed for the most part in terms of adjustments to heme structure, movement of internally bound water molecules and segmental thermal parameter changes along the polypeptide chain, rather than as explicit polypeptide chain positional shifts, which are found to be minimal. This result is emphasized by the retention of all main-chain to main-chain hydrogen bond interactions in both oxidation states. Observed thermal factor changes primarily affect four segments of polypeptide chain. Residues 37-39 show less mobility in the oxidized state, with Arg38 and its side-chain being most affected. In contrast, residues 47-59, 65-72 and 81-85 have significantly higher thermal factors, with maximal increases being observed for Asn52, Tyr67 and Phe82. The side-chains of two of these residues are hydrogen bonded to the internally bound water molecule, Wat166, which shows a large 1.7 A displacement towards the positively charged heme iron atom in the oxidized protein. Further analyses suggest that Wat166 is a major factor in stabilizing both oxidation states of the heme through differential orientation of dipole moment, shift in distance to the heme iron atom and alterations in the surrounding hydrogen bonding network. It also seems likely that Wat166 movement leads to the disruption of the hydrogen bond from the side-chain of Tyr67 to the Met80 heme ligand, thereby further stabilizing the positively charged heme iron atom in oxidized cytochrome c. In total, there appear to be three regions about which oxidation state-dependent structural changes are focussed. These include the pyrrole ring A propionate group, Wat166 and the Met80 heme ligand. All three of these foci are linked together by a network of intermediary interactions and are localized to the Met80 ligand side of the heme group. Associated with each is a corresponding nearby segment of polypeptide chain having a substantially higher mobility in the oxidized protein.(ABSTRACT TRUNCATED AT 400 WORDS)

PubMed: 1311391
DOI: 10.1016/0022-2836(92)90255-I

実験手法

X-RAY DIFFRACTION (1.9 Å)