Caracterização de proteinases envolvidas na geração de peptídeos antimicrobianos no intestino de Rhipicephalus (Boophilus) microplus. / CE. Characterization of proteinases involved in the generation of antimicrobial peptides in the gut of Rhipicephalus (Boophilus) microplus.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2010

RESUMO

It is known that hemoglobin is a rich source of antimicrobial peptides (hemocidins). The first hemoglobin-derived hemocidin characterized in ticks was the peptide Hb33-61, which is active against Gram-positive bacteria and fungi. It is believed that hemocidins are endogenously generated in the tick gut. In this work we biochemically characterized a cathepsin D, designated BmAP. Expression analysis by qRT-PCR showed that it is expressed predominantly in the gut. Through LC-MS/MS, we determined the cleavage specificity of BmAP using bovine hemoglobin, and we verified that hydrophobic residues were preferentially cleaved at the subsites P1 and P1. We also investigated the cleavage specificity of the intestinal cathepsin L BmCL1, using a positional scanning synthetic combinatorial library and through in vitro hemoglobinolysis. BmCL1 preferred aliphatic residues at P2 and polar residues at P1 and P1. Also, it hydrolysed the subunit of bovine hemoglobin at A63/A64, generating peptides with a primary structure similar to Hb 33-61. Hemoglobinolysis with BmAP and/or BmCL1 resulted in the formation of some hemocidins, corroborating the hypothesis that these proteinases are involved in the endogenous generation of antimicrobial peptides

ASSUNTO(S)

aspártico- proteinases cisteína-proteinases rhipicephalus (boophilus) microplus aspartic proteinases antimicrobial peptides hemoglobinolysis peptídeos antimicrobianos cysteine proteinases rhipicephalus (boophilus) microplus hemoglobinólise

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