Hans Hitz

Primary structure of ribosomal protein S6 from the wild type and a mutant of Escherichia coli

Ribosomes were isolated from E. coli, strain P, as previously described [S] . After extraction of ribosomal proteins by acetic acid protein S6 was separated from the other proteins by a two step elution procedure followed by a gradient elution on DEAE-cellulose. This resulted in several forms of S6 as described below and elsewhere in detail [4]. Amino acid analyses were done on a Durrum D-500 analyzer and peptide mapping on cellulose thin-layer plates. Peptides obtained after cleavage with trypsin, chymotrypsin, thermolysin and staphylococcus protease [6] digestion were separated on sulfoethyl-cellulose followed by paper chromatography [7]. The two peptides obtained by specific cleavage of the protein at its single tryptophanyl bond using BNPSskatol(2 (2 -nitrophenyl-sulfenyl) -3 methyl 3’ bromoindolenine [8] were separated by gel filtration on Sephadex Gl 00.