A novel peptide from the ACEI/BPP-CNP precursor in the venom of Crotalus durissus collilineatus.
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 Aird and Kaiser (1986, unpublished) previously isolated and sequenced a peptide of 11 residues (TPPAGPDVGPR) from Crotalus viridis viridis venom.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.
Higuchi
Shigesada
S
Showa University School of Pharmaceutical Sciences, Shinagawa-ku, Tokyo 142-8555, Japan.
Murayama
Nobuhiro
N
Saguchi
Ken-ichi
K
Ohi
Hiroaki
H
Fujita
Yoshiaki
Y
da Silva
Nelson Jorge
NJ
de Siqueira
Rodrigo José Bezerra
RJ
Lahlou
Saad
S
Aird
Steven D
SD
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
D000806:Angiotensin-Converting Enzyme Inhibitors; D003435:Crotalid Venoms; D018076:DNA, Complementary; D009842:Oligopeptides; C006791:bradykinin potentiating factors; D020098:Natriuretic Peptide, C-Type