1CHJ

STRUCTURAL STUDIES OF THE ROLES OF RESIDUES 82 AND 85 AT THE INTERACTIVE FACE OF CYTOCHROME C

1CHJ の概要

• エントリーDOI: 10.2210/pdb1chj/pdb
• 関連するPDBエントリー: 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: 12786.36

構造登録者

Lo, T.P.,Brayer, G.D. (登録日: 1994-06-01, 公開日: 1994-12-20, 最終更新日: 2021-03-03)

主引用文献

Lo, T.P.,Guillemette, J.G.,Louie, G.V.,Smith, M.,Brayer, G.D.
Structural studies of the roles of residues 82 and 85 at the interactive face of cytochrome c.
Biochemistry, 34:163-171, 1995

PubMed Abstract: A combination of structural, functional, and mutagenic experiments has been used to study the roles of the invariant Phe82 and highly conserved Leu85 residues in cytochrome c, especially with respect to the complexation interface with electron transfer partners and maintenance of the hydrophobic heme pocket. Structural analyses show that the F82Y, L85A, and F82Y/L85A mutant proteins all retain the characteristic cytochrome c fold, but that conformational alterations are introduced in the direct vicinity of the mutation sites. In particular, the additional hydroxyl group of Tyr82 is in direct spatial conflict with the side chain of Leu85 in the F82Y mutant protein, leading to rotation of the side chain of Tyr82 out toward the protein surface. This strain is relieved in the F82Y/L85A mutant protein where the phenyl ring of Tyr82 is accommodated in a conformation comparable to that of the phenylalanine normally present at this location. In addition, the available space vacated by the replacement of Leu85 with an alanine allows for the inclusion of two new internal water molecules, one of which is bound to Tyr82 and the other to Arg13. In contrast, in the L85A mutant protein, no internal water molecules are observed in this exclusively hydrophobic pocket, which is partially filled by shifts in nearby side chains. Overall, the conformational changes observed result from the optimization of side chain packing to reflect the spatial requirements of new side chains, the minimization of both vacant internal space and the solvent exposure of hydrophobic groups, and the attainment of maximal hydrogen bonding between available polar groups.(ABSTRACT TRUNCATED AT 250 WORDS)

PubMed: 7819192
DOI: 10.1021/bi00001a020

実験手法

X-RAY DIFFRACTION (1.9 Å)