Structural organization of precursor proteins.
A, nucleotide sequence of ms9.1 cDNA accompanied by deduced amino acid sequence. The signal peptide sequence is marked in bold, determined mature peptide sequences are underlined, and the Ms 9a-1 peptide is highlighted in gray. B, alignment of protein sequences of Ms 9a-1 precursors deduced from ms9.1 and ms9.2 genes. The signal peptide sequences are shown in italics, and different amino acids are in bold. C, multiple sequence alignment for three novel peptides from M. senile and other sea anemone toxins from structural class 9a: peptide U-SHTX-Sdd11 (C0HJB4) from Homostichanthus duerdeni; SHTXI/2 (P0C7W7) from Stichodactyla haddoni; Bcg III 23.41 toxin (P86466) from Bunodosoma cangicum; Am-1 (P69929) from Antheopsis maculata; Ugr 9a-1 (S4S1V7) from U. grebelnyi. Residues identical to the Ms 9a-1 sequence are highlighted. The cysteine distribution pattern for structural class 9a is shown at the bottom.