Yeast iso‐l‐cytochrome c: Genetic analysis of structural requirements

FEBS Letters

Sherman, Fred²  Hampsey, D.Michael¹  Dast, Goutam² 

[1] Departments of Biophysics University of Rochester Medical Center, Rochester, NY 14642, USA;Biochemistry, University of Rochester Medical Center, Rochester, NY 14642, USA

关键词: cycl missense mutation;    Cytochrome c phylogeny;    Heme attachment;    Iso-l-cytochrome c;    Protein stability;    (Saccharomyces cerevisiae);   

DOI  :  10.1016/0014-5793(88)80834-2

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

We describe the use of classical and molecular genetic techniques to investigate the folding, stability, and enzymatic requirements of iso-l-cytochrome c from the yeast Saccharomyces cerevisiae. Interpretation of the defects associated with an extensive series of altered forms of iso-l-cytochrome c was facilitated by the recently resolved three dimensional structure of iso-l-cytochrome c [(1987) J. Mol. Biol. 199, 295–314], and by comparison with the phylogenetic series of eukaryotic cytochromes c. Residue replacements that abolish iso-l-cytochrome c function appear to do so by affecting either heme attachment or protein stability; no replacements that abolish electron transfer function without affecting protein structure were uncovered. Most nonfunctional forms retained at least partial covalent attachment to the heme moiety; heme attachment was abolished only by replacements of Cys19 and Cys22, which are required for thioether linkage, and His23, a heme ligand. Replacements were uncovered that retain function at varying levels, including replacements at evolutionarily conserved positions, some of which were structurally and functionally indistinguishable from wild type iso-l-cytochrome c.

【 授权许可】

Unknown