Novel peptides from assassin bugs (Hemiptera: Reduviidae): isolation, chemical and biological characterization.
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 omega-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 beta-turns similar to that of omega-conotoxins GVIA and MVIIA. Electrophysiological experiments demonstrated that sPtu1 reversibly blocks the N-type calcium channels expressed in BHK cells.
Corzo
G
G
Suntory Institute for Bioorganic Research, Osaka, Japan. corzo@sunbor.or.jp
Adachi-Akahane
S
S
Nagao
T
T
Kusui
Y
Y
Nakajima
T
T
D000595:Amino Acid Sequence; D000818:Animals; D002853:Chromatography, Liquid; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry / Q000302:isolation & purification*; D011487:Protein Conformation; D020064:Reduviidae / Q000737:chemistry*; D017386:Sequence Homology, Amino Acid; D014688:Venoms / Q000737:chemistry*; D020960:omega-Conotoxins / Q000737:chemistry
D010455:Peptides; D014688:Venoms; D020960:omega-Conotoxins