A Superhyperfine Interaction Involving 33S in the Iron-containing Proteins of Azotobacter vinelandii

Abstract

Abstract A line-broadening effect attributable to 33S was observed in the asymmetrical electron spin resonance signals at g = 1.94 and 2.01 characteristic of non-heme iron proteins of Azotobacter vinelandii. The line broadening is believed to be due to unresolved superhyperfine splitting by the 33S nucleus. The observation implies an iron-sulfur interaction in at least one species of these proteins in A. vinelandii.