INTERACTION OF EF-TU WITH EF-TS - SUBSTITUTION OF HIS-118 IN EF-TU DESTABILIZES THE EF-TU-CENTER-DOT-EF-TS COMPLEX BUT DOES NOT PREVENT EF-TS FROM STIMULATING THE RELEASE OF EF-TU-BOUND GDP

Elongation factor Tu from Escherichia coli with His118 substituted by glycine (EF-TuH118G) was found to be defective in complex formation wi th EF-Ts. EF-Ts in excess failed to dissociate kirromycin from the EF- TuH118G kirromycin complex and to form a stable complex with EF-TuH118 G on column chromatography. However, the stimulatory effect of EF-Ts o n GDP dissociation from EF-TuH118G GDP and on poly(U)-directed poly(Ph e) synthesis catalyzed by EF-TuH118G was only partially influenced. Th ese results indicate that His118, while very important for the formati on of a stable EF-Tu EF-Ts complex, is not essential for the transmiss ion of the EF-Ts-dependent signal accelerating the release of the EF-T u-bound GDP. (C) 1998 Federation of European Biochemical Societies.