Figure 1

Figure 1

RP-HPLC/ESI-MS analyses of the synthesized conopressins and alignment of conopressin-related sequences. (A) Alignment of conopressin-related sequences. The asterisks * indicate an amidated C-terminal. Conopressin-M1 and M2 with γ-conopressin-vil are the only sequences that display a negatively charged amino acid at position 8. Interestingly, conopressin-M1 also displays an unusual proline residue at position 3. The highly conserved glycine residue at position 9 is replaced by a serine residue in conopressin-M1 and M2. (B) RP-HPLC/ESI-MS analyses of the synthesized conopressins. Acetonitrile (ACN) gradient from 0% to 30% over 30 min. For Con-M1 the two peaks display the same mass, possibly caused by the two proline residues inducing cis-trans isomerization causing dynamic conformational exchange leading to the splitting of the UV chromatogram peak [16,17,18]. The asterisk (*) on ESI-MS insets indicate an ion resulting from in source fragmentation of the proline residue [19].