Isolation and biochemical characterization of bradykinin-potentiating peptides from Bitis gabonica rhinoceros

 

Tamara M. Fucase¹, Juliana M. Sciani², Ingrid Cavalcante², Vincent L. Viala¹, Bruno B. Chagas¹, Daniel C. Pimenta², Patrick J. Spencer¹

 

1 Biotechnology Center, Nuclear and Energy Research Institute (IPEN), Av. Lineu Prestes, 2242, São Paulo, SP CEP 05508-000, Brazil.

2 Laboratory of Biochemistry and Biophysics, Butantan Institute, Av. Vital Brasil, 1500, São Paulo, SP CEP 05503-900, Brazil.

 

ABSTRACT

Background:

Venoms represent a still underexplored reservoir of bioactive components that might mitigate or cure diseases in conditions in which conventional therapy is ineffective. The bradykinin-potentiating peptides (BPPs) comprise a class of angiotensin-I converting enzyme (ACE) inhibitors. The BPPs usually consist of oligopeptides with 5 to 13 residues with a high number of proline residues and the tripeptide Ile-Pro-Pro (IPP-tripeptide) in the C-terminus region and have a conserved N-terminal pyroglutamate residue. As a whole, the action of the BPPs on prey and snakebite victims results in the decrease of the blood pressure. The aim of this work was to isolate and characterize novel BPPs from the venom of Bitis gabonica rhinoceros.

Methods:

The crude venom of B. g. rhinoceros was fractionated by size exclusion chromatography and the peptide fraction (<7 kDa) was separated by reverse phase chromatography (RP-HPLC) and analyzed by ESI-IT-TOF-MS/MS. One new BPP was identified, synthetized and assayed for ACE inhibition and, in vivo, for edema potentiation.

Results:

Typical BPP signatures were identified in three RP-HPLC fractions. CID fragmentation presented the usual y-ion of the terminal P-P fragment as a predominant signal at m/z 213.1. De novo peptide sequencing identified one Bothrops-like BPP and one new BPP sequence. The new BPP was synthesized and showed poor inhibition over ACE, but displayed significant bradykinin-induced edema potentiation.

Conclusions:

So far, few BPPs are described in Viperinae, and based on the sequenced peptides, two non-canonical sequences were detected. The possible clinical role of this new peptides remains unclear.

 

Keywords: Peptide; Hypotension; Viperinae

 

Received: November 24, 2016.

Accepted: June 14, 2017.

 

Correspondence: pspencer@ipen.br

 

Authors’ contributions

TMF performed the aqueous chromatographic procedures, and contributed to the enzymatic and in vivo assays and to the elaboration of the manuscript. JMS contributed to the de novo sequencing, in vivo and enzymatic assays and to the writing of the manuscript. IC contributed with the RP-HPLC assays, as well as with the enzymatic assays. VLV contributed with the de novo sequence analysis and with the final writing of the manuscript. BBC contributed with all the purification steps. DCP coordinated all the peptide characterization procedures and was involved in the final edition of the manuscript. PJS provided the venom, developed the aqueous chromatography procedures and participated in the final edition of the manuscript. All authors read and approved the final manuscript.

 

Competing interests

The authors declare that they have no competing interests.