Site-directed mutagenesis of Escherichia coli succinyl-CoA synthetase. beta-Cys325 is a nonessential active site residue.

C. J. Mann, Stephen C Hardies, J. S. Nishimura

Resultado de la investigación: Articlerevisión exhaustiva

9 Citas (Scopus)

Resumen

Chemical modification experiments have shown that sulfhydryl groups play an important role in the mechanism of action of Escherichia coli succinyl-CoA synthetase. One of these sulfhydryl groups has been localized in the beta-subunit of the enzyme using the coenzyme A affinity analog, CoA disulfide-S,S-dioxide (Collier, G. E., and Nishimura, J. S. (1978) J. Biol. Chem. 253, 4938-4943). Recently, it has been shown that the reactive sulfhydryl group resides in Cys325 (Nishimura, J. S., Mitchell, T., Ybarra, J., and Matula, J. M., submitted to Eur. J. Biochem. for publication). In the present study, we have changed Cys325 to a glycine residue using the technique of site-directed mutagenesis and have purified the mutant enzyme to homogeneity. The resulting mutant enzyme is 83% as active as wild type enzyme. In contrast to wild type succinyl-CoA synthetase, the mutant is refractory to chemical modification by CoA disulfide-S,S-dioxide and methyl methanethiolsulfonate. It is also less reactive with N-ethylmaleimide. Thus, beta-Cys325 is a nonessential active site residue.

Idioma originalEnglish (US)
Páginas (desde-hasta)1457-1460
Número de páginas4
PublicaciónJournal of Biological Chemistry
Volumen264
N.º3
EstadoPublished - ene. 25 1989
Publicado de forma externa

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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