Novel peptides from assassin bugs (Hemiptera: Reduviidae): isolation, chemical and biological characterization

[摘要]

Three novel peptides were isolated from the venomous saliva of predatory reduviids. They were identified by mass spectrometry and HPLC analysis and consist of 34–36 amino acid residues. They are relatively homologous to the calcium channel blockers ω-conotoxins from marine cone snails and belong to the four-loop Cys scaffold structural class. Ptu1, the shortest peptide, was chemically synthesized (sPtu1) and co-eluted with its native form. Circular dichroism spectra of the sPtu1 showed a high content of β-turns similar to that of ω-conotoxins GVIA and MVIIA. Electrophysiological experiments demonstrated that sPtu1 reversibly blocks the N-type calcium channels expressed in BHK cells.

[学科分类] 生物化学/生物物理

[关键词] Assassin bug;Conotoxin;Peptide;N-type calcium channel;Four-loop scaffold;Circular dichroism;Ptu1;Ado1;and lob1;peptides from the assassin bugs Peirates turpis;Agriosphodrus dohrni;and Isyndus obscurus respectively;sPtu1 and sAdo1;synthetic C-terminally carboxylated forms of Ptu1 and Ado1 respectively;GVIA;ω-conotoxin from Conus geographus;MVIIA;ω-conotoxin from Conus magus;TCEP;Tris-(2-carboxy-ethyl)phosphine;CDAP;1-cyano-4-dimethylamino-pyridinium tetrafluoroborate;MALDI-TOF MS;matrix-assisted laser desorption/ionization time-of-flight mass spectrometry;CZE;capillary zone electrophoresis;CD;circular dichroism