Amino acid sequences of two sulfhydryl-containing tryptic peptides of the polypeptide chain elongation factor Tu

Abstract

The primary structure around the sulfhydryl groups of the polypeptide chain elongation factor Tu has been investigated. The tryptic peptides containing sulfhydryl groups were separated from other peptides by affinity chromatography using a p-chloromercuribenzoate-agarose column. Two sulfhydryl-containing polypeptides were further purified by DEAE-Sephadex column chromatography after modification with iodo[ 3H]acetic acid. The amino acid sequences of a 15-residue segment containing the sulfhydryl essential for aminoacyl-tRNA binding (SH 2) and a 10-residue segment containing the non-reactive sulfhydryl (SH 3) have been determined using the manual method of the sequential Edman degradation. The amino acid sequences of SH 2- and SH 3-peptides were shown as His-Tyr-Ala-His-Val-Asp-Cys-Pro-Gly-His-Ala-Asp-Tyr-Val-Lys, and Ser-Thr-Cys-Thr-Gly-Val-Glu-Phe-Arg-Lys, respectively.