A NEW GLYCINE-RICH ANTIMICROBIAL PEPTIDE FROM SKIN SECRETION OF THE SOUTH AMERICAN FROG Leptodacytlus pentadactylus

FONTENELE-BERTO R. (1), CORDEIRO-SOUSA J. (1), OLIVEIRA R. G. (1), REBOUÇAS JR J. P. (1), HONÓRIO JR J.E.R. (2), OLINDA A. C. C. (1), CARVALHO I. F. (1), ADED DA SILVA P. (1), FONTENELE-CARDI N. C. (4), PIMENTA D. C. (3), CARDI B. A. (1,2), CARVALHO K. M. (1)

(1) Laboratório de Toxinologia e Farmacologia Molecular, UECE; (2) Laboratório de Animais Peçonhentos, UECE; (3) Centro de Toxinologia Aplicada (CAT/CEPID – FAPESP), Instituto Butantan ; (4) Hospital São José de Doenças Infecciosas, Ceará.

Skin granular glands of anurans species (frog and toad) synthesize and store polypeptides with a broad spectrum of antimicrobial activity that play an important role in the innate immunity and constitute the first-line defense against invading pathogens. This study describes the purification and the partial sequence of a new peptide with bacterial growth inhibitory activity present in high concentration in skin secretion from L. pentadactylus. Adult specimens of L. pentadactylus were collected in Paraipaba (Ceará, Brazil) and maintained in captivity. The secretion from their skin was obtained by electrical stimulation (2-7V), collected in a beaker freezing and immediately lyophilized. The antimicrobial peptide (Lpg) was purified by HPLC with a C18 column (25X250mm), eluted with a flow of 4,5ml/min and using a 0-80% linear gradient of acetonitrile. The molecular mass was analyzed by ESI-Q-TOF Ultima API (Micromass). In order to verify antimicrobial activity, Lpg was tested against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. The results showed that Lpg is capable to inhibit the growth bacterial of Pseudomonas aeruginosa at 200mM level. The analyzed compound is a 1762 Da peptide with 22 amino acid residues (60% glycine, 36% leucine and 4% of praline). This frog peptide should be classified into category of glycine-rich antimicrobial peptides. Structurally it is similar to acanthoscurrin, a peptide antimicrobial isolation of tarantura spider Acanthoscurria gomesiana. The results suggest that LPG may contribute to the improvement of a new antibacterial drug design for future therapeutic uses.

KEY WORDS: Leptodactylus, peptide glycine-rich, antimicrobial activity

FINANCIAL SUPPORT: FUNCAP, CAPES, CNPq

CORRESPONDENCE TO: carvalhokris@gmail.com