Download MendeleyStructure and mechanism of a proline-specific aminopeptidase from Escherichia coli.
Wilce, M.C., Bond, C.S., Dixon, N.E., Freeman, H.C., Guss, J.M., Lilley, P.E., Wilce, J.A.(1998) Proc Natl Acad Sci U S A 95: 3472-3477
- PubMed: 9520390
- DOI: https://doi.org/10.1073/pnas.95.7.3472
- Primary Citation of Related Structures:
1A16, 1JAW - PubMed Abstract:
The structure of the proline-specific aminopeptidase (EC 3.4.11.9) from Escherichia coli has been solved and refined for crystals of the native enzyme at a 2.0-A resolution, for a dipeptide-inhibited complex at 2.3-A resolution, and for a low-pH inactive form at 2.7-A resolution. The protein crystallizes as a tetramer, more correctly a dimer of dimers, at both high and low pH, consistent with observations from analytical ultracentrifuge studies that show that the protein is a tetramer under physiological conditions. The monomer folds into two domains. The active site, in the larger C-terminal domain, contains a dinuclear manganese center in which a bridging water molecule or hydroxide ion appears poised to act as the nucleophile in the attack on the scissile peptide bond of Xaa-Pro. The metal-binding residues are located in a single subunit, but the residues surrounding the active site are contributed by three subunits. The fold of the protein resembles that of creatine amidinohydrolase (creatinase, not a metalloenzyme). The C-terminal catalytic domain is also similar to the single-domain enzyme methionine aminopeptidase that has a dinuclear cobalt center.
Organizational Affiliation:
Department of Biochemistry, University of Sydney, New South Wales 2006, Australia.
