Peptides and Proteins of Brazilian Amphibians

Bloch Jr., C.(1)

(1)Laboratório de Espectrometria de Massa; Embrapa Recursos Genéticos e Biotecnologia. SAIN Parque Rural Av.W3 Norte 70 770-900;  Brasília, DF.

Amphibian skin secretion is a somewhat unique source of bioactive material. Ranging from simple sugars, alkaloids, amines, opioid substances, hormones, neurotransmitters to clearly established antibiotics [1], antimicrobial peptides [2] and protease inhibitors [3]. As a rule, a given amphibian species secretes a unique repertoire of small sized antimicrobial peptides through specialized epithelial cells. Most of them share overlapping structural and sequence features, such as cationic residues, an amphiphilic alpha-helix, and a sequence of 10 to 46 residues long. The presence of these related peptides in the frog skin plays a primary role in a primitive but elaborated innate host defense mechanism [4]. It is a chemical shield, against a wide range of invaders at their first point of contact, the skin, mucous membranes or other surfaces. This work reports the results of a systematic screening, functional investigation and structural analysis of a number of bioactive molecules found in the water-soluble skin secretions of amphibians from the Brazilian biodiversity. Among the studied genera are: Phyllomedusa, Physalaemus, Osteocephalus, Hyla, Brachycephalusand Trachycephalus.

References

1) HANCOCK, R.E.W. and LEHRER, R.I., (1998) Trends in Biotechnology 16:82-88.

2) HANCOCK, R.E.W. and DIAMOND, G., (2000) Trends in Microbiology 8,9:402-410.

3) CONLON, J.M. and KIM,J.B. (2000) Biochem. Biophys. Res. Comm. 279 (3):961-964.

4) GURA, T., (2001) Science 291:2068-2071.

CORRESPONDENCE TO:

Bloch Jr., C., Laboratório de Espectrometria de Massa; Embrapa Recursos Genéticos e Biotecnologia. SAIN Parque Rural Av.W3 Norte 70 770-900;  Brasília, DF, Brasil, Email: cbloch@cenargen.embrapa.br