A new binding site involving the C-terminal domain to design specific inhibitors of PepX.
PepX is a X-prolyl dipeptidyl aminopeptidase of S15 family that cleaves dipeptides from the N-terminus of polypeptides having a proline or alanine residue at the second position. Involved in bacterial nutrition and in peptide maturation, this serine exopeptidase, counterpart of the mammalian DDP-4, has been proposed to play a role in pathogenicity for Streptococci and to be a promising target against trypanosomes. Searching for specific inhibitors, we undertook docking simulations on the whole surface of PepX from Lactococcus lactis, type example of the S15 family, which revealed a new putative binding site in connection with the active site and involving the C-terminal domain. Accordingly to the results of the computations, we synthesized two peptidomimetics of low molecular weight: the valinephenylpiperazine and the valine-isopropylpiperazine that can accommodate to this putative binding site. Experiments revealed that the valine-phenylpiperazine was an uncompetitive inhibitor whereas the valine-isopropylpiperazine showed to be an activator of the enzyme activity. The valine-phenylpiperazine is interacting with ASN 379, GLU 383, GLU 474, residues in connection with the specificity and active sites, and with the residues from the C-terminal domain LEU 693, GLU 710 and GLN 712. These results point out a role of the C-terminal domain in controlling access to the active site of enzymes of the S15 family, like PepX, the cocaine esterase or the alpha-amino acid ester hydrolase, and could have applications in human health giving new perspectives to struggle against streptococci or trypanosomes by designing inhibitors specific to the S15 family of enzymes.
Laboratoire de Biotechnologies et Pharmacologie Génétique Appliquée, Ecole Normale Supérieure, 94235 Cachan cedex, France.
Joseph
J
André
Mathieu
M
Bach
Juan
J
Xie
Pascal
P
Rigolet
D001665:Binding Sites / Q000235:genetics; D020134:Catalytic Domain; D018819:Dipeptidyl Peptidase 4 / Q000737:chemistry; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D004789:Enzyme Activation; D020536:Enzyme Activators / Q000138:chemical synthesis / Q000494:pharmacology; D006801:Humans; D007700:Kinetics; D013294:Lactococcus lactis / Q000201:enzymology; D008958:Models, Molecular; D062105:Molecular Docking Simulation; D010879:Piperazines / Q000138:chemical synthesis / Q000494:pharmacology; D011480:Protease Inhibitors / Q000138:chemical synthesis / Q000494:pharmacology; D013291:Streptococcus / Q000201:enzymology / Q000472:pathogenicity; D014349:Trypanosoma cruzi / Q000201:enzymology; D014633:Valine / Q000031:analogs & derivatives / Q000138:chemical synthesis / Q000494:pharmacology
C581682:1-valyl-4-isopropylpiperazine; C581683:1-valyl-4-phenylpiperazine; D020536:Enzyme Activators; D010879:Piperazines; D011480:Protease Inhibitors; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases; C098392:PepX dipeptidyl aminopeptidase; D018819:Dipeptidyl Peptidase 4; D014633:Valine