title: The structural basis for catalysis and specificity of the X-prolyl dipeptidyl aminopeptidase from Lactococcus lactis.
abstract: The X-prolyl dipeptidyl aminopeptidase (X-PDAP) from Lactococcus lactis is a dimeric enzyme catalyzing the removal of Xaa-Pro dipeptides from the N terminus of peptides. The structure of the enzyme was solved at 2.2 A resolution and provides a model for the peptidase family S15. Each monomer is composed of four domains. The larger one presents an alpha/beta hydrolase fold and comprises the active site serine. The specificity pocket is mainly built by residues from a small helical domain which is, together with the N-terminal domain, essential for dimerization. A C-terminal moiety probably plays a role in the tropism of X-PDAP toward the cellular membrane. These results give new insights for further exploration of the role of the enzymes of the SC clan.
authors.affiliation: L.U.R.E. Centre Universitaire Paris-Sud, Bât. 209D-BP 34, F-91898 Orsay Cedex, France. rigolet@lure.u-psud.fr
authors.forename: Pascal
authors.initials: P
authors.lastname: Rigolet
authors.forename: Ingrid
authors.initials: I
authors.lastname: Mechin
authors.forename: Marie-Madeleine
authors.initials: MM
authors.lastname: Delage
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Chich
mesh_terms: D000595:Amino Acid Sequence; D002384:Catalysis; D019281:Dimerization; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases / Q000737:chemistry / Q000378:metabolism*; D013294:Lactococcus lactis / Q000201:enzymology*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D017510:Protein Folding; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity
chemical_list: D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases; C098392:PepX dipeptidyl aminopeptidase