Isolation and sequence determination of peptides in the venom of the spider wasp (Cyphononyx dorsalis) guided by matrix-assisted laser desorption/ionization time of flight (MALDI-TOF) mass spectrometry

Micro-scale (sub-pmol) isolation and sequence determination of three peptid es from the venom of the solitary spider wasp Cyphononyx dorsalis is descri bed. We isolated two novel peptides Cd-125 and Cd-146 and a known peptide T hr(6)-bradykinin from only two venom sacs of solitary spider wasp Cyphonony x dorsalis without bioassay-guided fractionation. but instead guided by MAL DI-TOF MS. The MALDI-TOF MS analysis of each fraction showed the purity and molecular weight of the components, which led to the isolation of the pept ides virtually without loss of sample amount. The sequences of the novel pe ptides Cd-125 (Asp-Thr-Ala-Arg-Leu-Lys-Trp-His) and Cd-146 (Ser-Glu-Thr-Gly -Asn-Thr-Val-Thr-Val-Lys-Gly-Phe-Ser-Pro-Leu-Arg) were determined by Edman degradation together with mass spectrometry. and finally corroborated by so lid-phase synthesis. The known peptide Thr(6)-bradykinin (Arg-Pro-Pro-Gly-P he-Thr-Pro-Phe-Arg) was identified by comparison with the synthetic authent ic specimen. This is the first example for any kinins to be found in Pompil idae wasp venoms. The procedure reported here can be applicable to studies on many other components of solitary wasp venoms with limited sample availa bility. (C) 2001 Elsevier Science Ltd. All rights reserved.