A Biochemical Characterization of Histidine-Dependent Mutants of Staphylococcus aureus

Abstract

Over 100 histidine-dependent mutants were isolated from strain 655 of Staphylococcus aureus. Paper chromatography was used to differentiate the mutants into classes according to their ability to accumulate Pauly-positive imidazoles. Mutants of class A accumulated 5-amino-l-ribosyl-4-imidazolecarbox-amide, mutants of class B accumulated imidazoleglycerol, and mutants of class C accumulated imidazoleacetol. Mutants of class D accumulated histidinol and were incapable of utilizing exogenous L-histidinol. A comparison of the accumulations obtained from mutants of S. aureus with accumulations obtained from previously characterized mutants of Salmonella typhimurium indicates that a similar, if not identical, pathway for the biosynthesisof L-histidine is used by these two species.