Amino acid sequence of flagellin of Bacillus subtilis 168. III. Tryptic peptides, N-bromosuccinimide peptides, and the complete amino acid sequence.

Of the 28 expected tryptic peptides from Bacillus subtilis 168 flagellin, 24 were isolated and sequenced. Several overlapping tryptic peptides were also characterized. Studies were also performed on two peptides of 142 and 162 residues isolated after cleavage of the flagellin molecule at the single tyrosine residue (residue 142) with N-bromosuccinimide. These studies together with the previous data on the cyanogen bromide peptides and the tryptic peptides from maleylated flagellin permitted the complete amino acid sequence to be established: (see article). The primary structure reveals no obvious regularities or major repetitions of homologous sequences. Hydrophobic residues are distributed randomly in the amino acid sequence. However, the distribution of charged residues is strikingly asymmetric. The NH2-terminal region (residues 1 to 101) possesses a net charge of 6 plus, the middle of the molecule (residues 102 to 203), a net charge of 9 minus, and the COOH terminal region (residues 204 to 304), a net charge of 4 minus.