Intramolecular long-range electron transfer in the hemerythrin monomer: a pulse radiolysis study.
The single sulfhydryl group (Cys-50) of the methemerythrin from Phascolosoma gouldii reacts with 5,5'dithiobis(2-nitrobenzoic acid) to form a mixed disulfide. The pulse radiolytically generated formate radical reduces this mixed disulfide to its radical anion. In turn, the disulfide radical anion reduces the protein two-iron center over a nominal distance of 13 A. The rate constant for this intramolecular electron transfer is approximately 15 s-1 at room temperature, pH 7. Between the two redox centers there is an equilibrium driving force of 0.78 V, measured by differential pulsed polarography.
Faraggi
M
M
Department of Chemistry, Nuclear Research Centre-Negev, Beer-Sheva, Israel.
Klapper
M H
MH
D000818:Animals; D002245:Carbon Dioxide; D003545:Cysteine; D005609:Free Radicals; D006422:Hemerythrin / Q000502:physiology*; D007448:Invertebrates; D046911:Macromolecular Substances; D008667:Metalloproteins / Q000502:physiology*; D010084:Oxidation-Reduction
D005609:Free Radicals; D006422:Hemerythrin; D046911:Macromolecular Substances; D008667:Metalloproteins; D002245:Carbon Dioxide; D003545:Cysteine