Modulated growth of Saccharomyces cerevisiae by altering the driving force of the reactions of cytochrome c: Marcus' theory in vitro and in vivo.
According to Marcus' theory, rates of electron transfer reactions depend parabolically on the free energy of reaction. Amino acid replacements in the electron transport protein cytochrome c produced a series of proteins which changed the free energy of reaction for cytochrome c in oxidative phosphorylation. This study shows that Marcus' theory of electron transfer can be applied to the reactions of redox-altered cytochromes c with cytochrome c1 both in vitro and in vivo. In vitro, isolation of physiologically relevant partners of cytochrome c suggests that a change in free energy of reaction of cytochrome c changes the rate of electron transfer with cytochrome bc1 complex as would be predicted by Marcus' theory of electron transfer. Furthermore, the reactivity pattern observed in vitro is paralleled in in vivo studies. In vivo the rates of growth of Saccharomyces cerevisiae, in which these alternatives have been incorporated, also are consistent with the change in free energy of the reactions of cytochrome c with cytochrome bc1 complex. This study suggests that Marcus' theory of electron transport can predict rates not only in vitro, in isolated protein-protein systems, but also in vivo, where the relative growth rates of yeast may be predicted from the in vitro results.
Komar-Panicucci
S
S
Department of Chemistry, Princeton University, New Jersey 08544-1009, USA.
Sherman
F
F
McLendon
G
G
D003574:Cytochrome c Group / Q000302:isolation & purification / Q000378:metabolism*; D004579:Electron Transport; D007700:Kinetics; D008954:Models, Biological; D010084:Oxidation-Reduction; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000254:growth & development*
D003574:Cytochrome c Group