A comparative kinetic analysis of the reactivity of plant, horse, and human respiratory cytochrome c towards cytochrome c oxidase.
Two synthetic genes coding for human and Arabidopsis cytochrome c, respectively, have been designed and constructed, and the recombinant proteins have been over-expressed in Escherichia coli cells. Thus a comparative analysis of the two heme proteins, including horse cytochrome c as a reference, has been performed. In addition to their physico-chemical properties, the redox behavior of the three proteins has been analyzed by following the kinetics of both their reduction by flavin semiquinones (lumiflavin, riboflavin, and FMN) and oxidation by cytochrome c oxidase. The resulting data indicate that the accessibility and electrostatic charge of the active site do not differ in a significant way among the three proteins, but human cytochrome c exhibits some intriguing differences when interacting with cytochrome c oxidase that could be related to the amino acid changes underwent by the latter along evolution.
Rodríguez-Roldán
Vicente
V
Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla y CSIC, Centro de Investigaciones Científicas Isla de la Cartuja, Sevilla, Spain.
García-Heredia
José M
JM
Navarro
José A
JA
Hervás
Manuel
M
De la Cerda
Berta
B
Molina-Heredia
Fernando P
FP
De la Rosa
Miguel A
MA
D000818:Animals; D017360:Arabidopsis / Q000201:enzymology*; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D045304:Cytochromes c / Q000378:metabolism*; D003576:Electron Transport Complex IV / Q000378:metabolism*; D005415:Flavins / Q000378:metabolism; D006736:Horses; D006801:Humans; D007700:Kinetics; D008928:Mitochondria / Q000201:enzymology*; D010084:Oxidation-Reduction / Q000187:drug effects; D011189:Potassium Chloride / Q000494:pharmacology
D005415:Flavins; D011189:Potassium Chloride; D045304:Cytochromes c; D003576:Electron Transport Complex IV