Insight into the active-site structure and function of cytochrome oxidase by analysis of site-directed mutants of bacterial cytochrome aa3 and cytochrome bo

• Published in: Journal of bioenergetics and biomembranes 1993-04, Vol.25 (2), p.121-136
• Main Authors: HOSLER, J. P, FERGUSON-MILLER, S, TECKLENBURG, M. M. J, BABCOCK, G. T, GENNIS, R. B, CALHOUN, M. W, THOMAS, J. W, HILL, J, LEMIEUX, L, JIXIANG MA, GEORGIOU, C, FETTER, J, SHAPLEIGH, J
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Bacteriology; Binding Sites; Biological and medical sciences; Cytochrome b Group; Cytochromes - chemistry; Cytochromes - genetics; Cytochromes - metabolism; Electron Transport Complex IV - chemistry; Electron Transport Complex IV - genetics; Electron Transport Complex IV - metabolism; Escherichia coli - enzymology; Escherichia coli Proteins; Fundamental and applied biological sciences. Psychology; Metabolism. Enzymes; Microbiology; Models, Structural; Molecular Sequence Data; Mutagenesis, Site-Directed; Protein Structure, Secondary; Recombinant Proteins - chemistry; Recombinant Proteins - metabolism; Rhodobacter sphaeroides - enzymology
• ISSN: 0145-479X; 1573-6881
• DOI: 10.1007/BF00762854

Cytochrome aa3 of Rhodobacter sphaeroides and cytochrome bo of E. coli are useful models of the more complex cytochrome c oxidase of eukaryotes, as demonstrated by the genetic, spectroscopic, and functional studies reviewed here. A summary of site-directed mutants of conserved residues in these two enzymes is presented and discussed in terms of a current model of the structure of the metal centers and evidence for regions of the protein likely to be involved in proton transfer. The model of ligation of the heme a3 (or o)-CuB center, in which both hemes are bound to helix X of subunit I, has important implications for the pathways and control of electron transfer.