This N-terminal domain adopts a secondary structure consisting of a helical bundle of eight alpha helices and three beta strands, with the last alpha helix connecting to the first strand of the catalytic domain. The first strand of the N-terminus also forms a small parallel beta sheet with strand five of the catalytic domain. This domain mediates dimerisation of the protein, with two proline residues present in the domain being critical for interaction (PUBMED:12377124).
This N-terminal domain adopts a secondary structure consisting of a helical bundle of eight alpha helices and three beta strands, with the last alpha helix connecting to the first strand of the catalytic domain. The first strand of the N terminus also forms a small parallel beta sheet with strand five of the catalytic domain. This domain mediates dimerisation of the protein, with two proline residues present in the domain being critical for interaction [(PUBMED:12377124)].
The structural basis for catalysis and specificity of the X-prolyldipeptidyl aminopeptidase from Lactococcus lactis.
Structure. 2002; 10: 1383-94
Display abstract
The X-prolyl dipeptidyl aminopeptidase (X-PDAP) from Lactococcus lactis isa dimeric enzyme catalyzing the removal of Xaa-Pro dipeptides from the Nterminus of peptides. The structure of the enzyme was solved at 2.2 Aresolution and provides a model for the peptidase family S15. Each monomeris composed of four domains. The larger one presents an alpha/betahydrolase fold and comprises the active site serine. The specificitypocket is mainly built by residues from a small helical domain which is,together with the N-terminal domain, essential for dimerization. AC-terminal moiety probably plays a role in the tropism of X-PDAP towardthe cellular membrane. These results give new insights for furtherexploration of the role of the enzymes of the SC clan.