A novel peptide from the ACEI/BPP-CNP precursor in the venom of Crotalus durissus collilineatus

• Published in: Comparative biochemistry and physiology. Toxicology & pharmacology 2006-10, Vol.144 (2), p.107-121
• Main Authors: Higuchi, Shigesada, Murayama, Nobuhiro, Saguchi, Ken-ichi, Ohi, Hiroaki, Fujita, Yoshiaki, da Silva, Nelson Jorge, de Siqueira, Rodrigo José Bezerra, Lahlou, Saad, Aird, Steven D.
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Anaphylatoxin C3a; Angiotensin-Converting Enzyme Inhibitors; Animals; Base Sequence; Blood Pressure - drug effects; Bradykinin-potentiating peptides; Crotalid Venoms - genetics; Crotalus - genetics; Crotalus durissus collilineatus; Crotalus viridis viridi; DNA, Complementary - genetics; Heart Rate - drug effects; Hypotensive peptides; In Vitro Techniques; Male; Molecular Sequence Data; Natriuretic Peptide, C-Type - genetics; Oligopeptides - genetics; Oligopeptides - pharmacology; Rats; Rats, Wistar; Rattlesnake venoms; Sequence Analysis, DNA
• ISSN: 1532-0456; 1878-1659
• DOI: 10.1016/j.cbpc.2006.04.006

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 Aird and Kaiser (1986, unpublished) previously isolated and sequenced a peptide of 11 residues (TPPAGPDVGPR) from Crotalus viridis viridis venom.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.