Ponente
Descripción
The enzymes ePepN and PfA-M1 are two M1 alanyl-aminopeptidases which are targets in the potential treatment of microbial infections and malaria, respectively. The classical inhibitor of M1-aminopeptidases is bestatin (non-selective). The synthetic bestatin-derived peptidomimetic KBE009 was previously identified as a PfA-M1 inhibitor with in vitro antimalarial activity. The objective of this work was to test a synthetic library of 10 bestatin (KBE009)-derived peptidomimetics and 21 tetrazole-peptidomimetics (TPMs) in the inhibition of recombinant ePepN (rePepN) and PfA-M1 (rPfA-M1), and to study the resultant structure-activity relationship. The main kinetic characteristics of the inhibition of both enzymes by bestatin were assessed. Bestatin is a non-competitive inhibitor of rePepN (Ki = 2.31 uM), and competitive of rPfA-M1 (Ki = 1.29 uM). None bestatin-derived peptidomimetic is a potent inhibitor. KBE053 (representative of this series) is an uncompetitive inhibitor of rePepN (Ki = 10.13 uM). Three TPMs were identified as potent and selective (regarding porcine M1-aminopeptidase) rePepN inhibitors. The structural characteristics of these compounds that are favorable for the inhibition were described. The most potent (IC50 = 0.26 uM) and selective (selectivity index = 23,461 times) inhibitor (TPM 11) is a non-competitive inhibitor of rePepN. The non-competitive inhibition, based on not coordination of the catalytic Zn2+, was predicted by molecular docking. TMP 2 showed in vitro antibacterial activity against Escherichia coli. None of the three identified inhibitors is a potent haemolytic agent, and only two compounds show moderate cytotoxic activity toward the murine myeloma P3X63Ag cells. This knowledge could contribute to the design of novel ePepN and PfA-M1 inhibitors with antibacterial and antimalarial activities.
