title: Sulfhydryl groups of Escherichia coli ribosomal protein S1. Location along the polypeptide chain.
abstract: The location of the functionally important -SH groups of Escherichia coli ribosomal protein S1 along the polypeptide chain has been determined using a cysteine-specific cleavage procedure. The two -SH groups of S1 are located at 57% and 67% of the polypeptide chain length from the NH2 terminus. The -SH group farther from the NH2 terminus is shown to be the more reactive one. Two truncated derivatives of S1 (S1-F1 and m1-S1) both contain two -SH groups. It has previously been shown that S1-F1 (which lacks the NH2-terminal region of S1) is inactive in unfolding nucleic acids, just as the N-ethylmaleimide derivative of S1. The present results therefore show that the formation and functioning of the nucleic acid unfolding domain of protein S1 requires the -SH group(s) as well as the NH2-terminal region.
mesh_terms: D003545:Cysteine / Q000032:analysis*; D004926:Escherichia coli / Q000032:analysis*; D005033:Ethylmaleimide; D010455:Peptides / Q000032:analysis; D012269:Ribosomal Proteins / Q000032:analysis*; D013861:Thiocyanates; D014508:Urea
chemical_list: D010455:Peptides; D012269:Ribosomal Proteins; D013861:Thiocyanates; C015494:ribosomal protein S1; D014508:Urea; D003545:Cysteine; D005033:Ethylmaleimide; C008658:2-nitro-5-thiocyanobenzoic acid