PURIFICATION AND CHARACTERIZATION OF A PUTATIVE ANTIMICROBIAL PEPTIDE ISOLATED FROM THE FROG Odontophrynus cultripes SKIN SECRETION

SENA, G.(1), FONTES, W.(2), SOUSA, M.V.(2), SCHWARTZ, C.A.(1), SCHWARTZ, E.F.(1), SEBBEN, A.(1), CASTRO, M.S.(1,2)

(1)Laboratório de Toxinologia, Departamento de Ciências Fisiológicas, IB, Universidade de Brasília; (2)Centro Brasileiro de Serviços e Pesquisas em Proteínas, Departamento de Biologia Celular, IB, Universidade de Brasília, Brasília, DF, Brasil.

Amphibian cutaneous secretions have been studied since a long time ago because they carry a large range of noxious substances. For example, they contain bioactive compounds represented by biogenic amines, steroids, alkaloids, peptides and proteins. Many of these substances are used in self-defense against predators and microorganisms. In this report, we describe the purification and characterization of one putative antimicrobial peptide obtained from Odontophrynus cultripes (Leptodactylidae) cutaneous secretion. Adult specimens of O. cultripes were collected in Luziânia/GO and maintained in captivity at the University of Brasília. Cutaneous secretion was obtained by mild electrical stimulation, lyophilized and stored at –20oC. The dried secretion was applied onto a C8 reversed phase column. One eluted fraction was individually rechromatographed using a C18 reversed-phase column and resulted in the purification of one homogenous peptide. This purified fraction was submitted to mass spectrometry analysis using MALDI-TOF technique (Reflex IV, Bruker Daltonics) and to Edman degradation using an automated protein sequencer (477A-120A, Applied Biosystems). This novel peptide has 18 amino acid residues and a molecular mass of 1.800 Da. This peptide shows sequence similarities to other antimicrobial peptides from amphibian species included in Brevenin and Uperin families.

Financial supported by: PIBIC/CNPq, FUB/UnB and FINATEC.

CORRESPONDENCE TO:

CASTRO, M.S., Laboratório de Toxinologia, Departamento de Ciências Fisiológicas, IB, Universidade de Brasília, Brasília, DF, 70910-900, Brasil, Email: mscastro@unb.br