Fig. 2. Complete amino acid sequence of Cn11. The N-terminal amino acid sequence up to residue 20 (underlined –d) was obtained by direct sequencing of a sample of native peptide, whose sequence was confirmed up to residue 34 with a reduced and carboxymethylated sample (underlined –RCM). Four additional sub-peptides obtained by enzymatic cleavage of alkylated toxin, followed by HPLC separation (as in Fig. 1, data not shown), were sequenced. They are under-labelled Tryp1 (positions 39–52) and Tryp2 (positions 55–62), for trypsin digestion and AspN1 (positions 20–44) and AspN2 (positions 51–61), for aspartic-N endopeptidase digestion. The last residue in position 63 was determined by mass spectrometry (under-labelled ms).