Interaction of EF-Tu with EF-Ts: substitution of His-118 in EF-Tu destabilizes the EF-Tu x EF-Ts complex but does not prevent EF-Ts from stimulating the release of EF-Tu-bound GDP

Abstract

Elongation factor Tu from Escherichia coli with His-118 substituted by glycine (EF-TuH118G) was found to be defective in complex formation with EF-Ts. EF-Ts in excess failed to dissociate kirromycin from the EF-TuH118G x kirromycin complex and to form a stable complex with EF-TuH118G on column chromatography. However, the stimulatory effect of EF-Ts on GDP dissociation from EF-TuH118G x GDP and on poly(U)-directed poly(Phe) synthesis catalyzed by EF-TuH118G was only partially influenced. These results indicate that His-118, while very important for the formation of a stable EF-Tu-EF-Ts complex, is not essential for the transmission of the EF-Ts-dependent signal accelerating the release of the EF-Tu-bound GDP.