The complete primary structure of protein L10 from the large subunit of the Escherichia coli ribosome has been determined. L10 is composed of 165 residues and has the amino acid composition: Asp6, Asn3, Thr9, Ser6, Glu14, Gln4, Pro5, Gly9, Ala33, Val15, Met5, Ile5, Leu15, Tyr3, Phe6, His1, Lys12, Arg13 and Cys1. The molecular weight of L10 is 17 738. The amino acid sequence was determined by a combination of automated Edman degradation of the intact protein in a modified Beckman sequentor and sequencing peptides obtained from digestions with trypsin, themolysin, Staphylococcus aureus protease and chymotrypsin. Further information was obtained from cyanogen bromide fragments and peptides resulting from digestion with trypsin after protection of the epsilon-amino groups of the lysine residues with exo-cis-3,6-endoxo-delta4-tetrahydrophthalic anhydride (ETPA).
