A NOVEL HEMOLYTIC PEPTIDE ISOLATED FROM THE SKIN SECRETION OF THE BRAZILIAN TREE-FROG Hyla biobeba (Anura: Hylidae)

Matsushita, R.H.(1,2), 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)Laboratório de Bioquímica e Química de Proteínas, Centro Brasileiro de Serviços e Pesquisas em Proteínas, Departamento de Biologia Celular, IB, Universidade de Brasília, Brasília, DF, Brasil.

Several biologically active components such as biogenic amines, alkaloids, steroids, peptides and proteins occur in amphibian skin secretions. These compounds exhibit a large array of pharmacological effects and have different functions. Many of them are probably used in self-defense against predators and may protect against microbial infections. Hemolytic activity has been described in the skin secretions of the toad Bombina variegata, the newt Triturus cristatus and the caecilian Siphonops paulensis. In this report, we describe the purification and partial characterization of a novel hemolytic peptide isolated from the skin secretions of adult specimens of the tree-frog Hyla biobeba Bokermann and Sazima, 1973. The frogs were collected in the Federal District and maintained in captivity at the University of Brasília. Secretions were obtained by mild electrical stimulation and were freeze-dried. Aliquots of dried secretion were applied to a C₈ reversed-phase column (Pharmacia Biotech, 4.6 x 250 mm). The eluted fractions were collected manually, lyophilized and tested for hemolytic activity. One hemolytic fraction was rechromatographedusing a C₁₈ reversedphase column (Vydac218TP54, Separations Group). The purified hemolysin was analyzed by MALDI-TOF (Reflex IV, Bruker) and sequenced by automated Edman degradation using an ABI 477A sequencer. This bioactive peptide had a molecular mass of 1.86 kDa and shared high sequence identity with other hemolytic peptides previously isolated from Hyla species by our group.

Financial supported by: FUB-UnB and FINATEC.

CORRESPONDENCE TO:

Castro, M.S, Laboratório de Toxinologia, Departamento de Ciências Fisiológicas, IB, Universidade de Brasília, Brasília, 70190-900, DF, Brasil, Email: mscastro@unb.br