title: A novel peptide from the ACEI/BPP-CNP precursor in the venom of Crotalus durissus collilineatus.
abstract: In crotaline venoms, angiotensin-converting enzyme inhibitors [ACEIs, also known as bradykinin potentiating peptides (BPPs)], are products of a gene coding for an ACEI/BPP-C-type natriuretic peptide (CNP) precursor. In the genes from Bothrops jararaca and Gloydius blomhoffii, ACEI/BPP sequences are repeated. Sequencing of a cDNA clone from venom glands of Crotalus durissus collilineatus showed that two ACEIs/BPPs are located together at the N-terminus, but without repeats. An additional sequence for CNP was unexpectedly found at the C-terminus. Homologous genes for the ACEI/BPP-CNP precursor suggest that most crotaline venoms contain both ACEIs/BPPs and CNP. The sequence of ACEIs/BPPs is separated from the CNP sequence by a long spacer sequence. Previously, there was no evidence that this spacer actually coded any expressed peptides. Aird and Kaiser (1986, unpublished) previously isolated and sequenced a peptide of 11 residues (TPPAGPDVGPR) from Crotalus viridis viridis venom. In the present study, analysis of the cDNA clone from C. d. collilineatus revealed a nearly identical sequence in the ACEI/BPP-CNP spacer. Fractionation of the crude venom by reverse phase HPLC (C(18)), and analysis of the fractions by mass spectrometry (MS) indicated a component of 1020.5 Da. Amino acid sequencing by MS/MS confirmed that C. d. collilineatus venom contains the peptide TPPAGPDGGPR. Its high proline content and paired proline residues are typical of venom hypotensive peptides, although it lacks the usual N-terminal pyroglutamate. It has no demonstrable hypotensive activity when injected intravenously in rats; however, its occurrence in the venoms of dissimilar species suggests that its presence is not accidental. Evidence suggests that these novel toxins probably activate anaphylatoxin C3a receptors.
authors.affiliation: Showa University School of Pharmaceutical Sciences, Shinagawa-ku, Tokyo 142-8555, Japan.
authors.forename: Shigesada
authors.initials: S
authors.lastname: Higuchi
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Murayama
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Saguchi
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Ohi
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Fujita
authors.forename: Nelson Jorge
authors.initials: NJ
authors.lastname: da Silva
authors.forename: Rodrigo José Bezerra
authors.initials: RJ
authors.lastname: de Siqueira
authors.forename: Saad
authors.initials: S
authors.lastname: Lahlou
authors.forename: Steven D
authors.initials: SD
authors.lastname: Aird
mesh_terms: D000595:Amino Acid Sequence; D000806:Angiotensin-Converting Enzyme Inhibitors; D000818:Animals; D001483:Base Sequence; D001794:Blood Pressure / Q000187:drug effects; D003435:Crotalid Venoms / Q000235:genetics*; D017839:Crotalus / Q000235:genetics*; D018076:DNA, Complementary / Q000235:genetics; D006339:Heart Rate / Q000187:drug effects; D066298:In Vitro Techniques; D008297:Male; D008969:Molecular Sequence Data; D020098:Natriuretic Peptide, C-Type / Q000235:genetics; D009842:Oligopeptides / Q000235:genetics* / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D017422:Sequence Analysis, DNA
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D003435:Crotalid Venoms; D018076:DNA, Complementary; D009842:Oligopeptides; C006791:bradykinin potentiating factors; D020098:Natriuretic Peptide, C-Type