3H8G: Bestatin Complex Structure Of Leucine Aminopeptidase From Pseudomonas Putida

Citation:
Abstract
The zinc-dependent leucine aminopeptidase from Pseudomonas putida (ppLAP) is an important enzyme for the industrial production of enantiomerically pure amino acids. To provide a better understanding of its structure-function relationships, the enzyme was studied by X-ray crystallography. Crystal structures of native ppLAP at pH 9.5 and pH 5.2, and in complex with the inhibitor bestatin, show that the overall folding and hexameric organization of ppLAP are very similar to those of the closely related di-zinc leucine aminopeptidases (LAPs) from bovine lens and Escherichia coli. At pH 9.5, the active site contains two metal ions, one identified as Mn(2+) or Zn(2+) (site 1), and the other as Zn(2+) (site 2). By using a metal-dependent activity assay it was shown that site 1 in heterologously expressed ppLAP is occupied mainly by Mn(2+). Moreover, it was shown that Mn(2+) has a significant activation effect when bound to site 1 of ppLAP. At pH 5.2, the active site of ppLAP is highly disordered and the two metal ions are absent, most probably due to full protonation of one of the metal-interacting residues, Lys267, explaining why ppLAP is inactive at low pH. A structural comparison of the ppLAP-bestatin complex with inhibitor-bound complexes of bovine lens LAP, along with substrate modelling, gave clear and new insights into its substrate specificity and high level of enantioselectivity.
PDB ID: 3H8GDownload
MMDB ID: 81369
PDB Deposition Date: 2009/4/29
Updated in MMDB: 2012/10
Experimental Method:
x-ray diffraction
Resolution: 1.5  Å
Source Organism:
Similar Structures:
Biological Unit for 3H8G: hexameric; determined by author and by software (PISA)
Molecular Components in 3H8G
Label Count Molecule
Proteins (6 molecules)
6
Cytosol Aminopeptidase
Molecule annotation
Chemicals (30 molecules)
1
6
2
6
3
6
4
6
5
6
* Click molecule labels to explore molecular sequence information.

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