Aspartate residues cytochrome

More recently, Yoshikawa,Tsukihara, and co-workers published a study of fully oxidized (PDB 1V54) and fully reduced (PDB 1V55) bovine heart cytochrome c oxidase structures. " In this study, they identified an aspartate residue, asp51, which undergoes a substantial change in position between the oxidized and reduced structures (see inset in Figure 7.41A). 

For cytochrome c peroxidase, the reduction involves two protein-protein one-electron transfers. There have been extensive studies of the physiologically relevant reaction that provide much support for very rapid formation of a precursory 1 1 electron-transfer complex [217]. Electrostatic interactions are a major factor in this process. Examination of the structure of CcP reveals a ring of aspartate residues that are arranged so as to be complementary with the distribution of highly conserved lysines that surround the exposed heme edge region of the... 

Paine MJ, McLaughlin LA, Flanagan JU, et al. Residues glutamate 216 and aspartate 301 are key determinants of substrate specificity and product regioselectivity in cytochrome P450 2D6. J Biol Chem 2003 278(6) 4021-4027. 

Ellis, S. W., Hayhurst, G. P., Smith, G., et al. (1995) Evidence that aspartic acid 301 is a critical substrate-contact residue in the active site of cytochrome P450 2D6. J. Biol. Chem. 270, 29,055-29,058. 

Figure 11 Molecular model of the complex between Ru-65-c) t bs and Cc. The geometry of the complex is the same as that of the complex involving native cytochrome bs proposed by Salemme. The heme groups (red), and the ruthenimn complex (green) are highhghted. The atoms forming an electron-transfer pathway between the ruthenimn complex and the heme group of Ru-65-c) t bs are colored yellow. The lysine and arginine residues are blue, while aspartate and glutamate residues are red ...

Some insights have come from mutation studies (Hosler et al. 1993,1996, Thomas et al. 1993, Fetter et al. 1995, Garcia-Horsman et al. 1995) and the X-ray structures of cytochrome c oxidase (IwATA et al. 1995, Tsukihara et al. 1995, Oster-MEiER et al. 1997, Yoshikawa et al. 1998) revealing at least two pathways that are common to bacterial and mammaUan oxidases, designated as the D and K channels due to an aspartate (D132) and a lysine (K362) which are key residues in these proton Aan-nels. 

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