Metal Ion Substitution in the Catalytic Site Greatly Affects the Binding of Sulfhydryl-containing Compounds to Leucyl Aminopeptidase.
From: Department of Physiology and Biochemistry, University of Pisa, I-56126 Pisa, Italy.
Biochemistry
- Publish Date: Mar 2006
- ISSN: 0006-2960
- Volume: 45
- Issue: 10
- Pages: 3226-34
- Medium: Print
- Language: English
- Citation (JAMA): Cappiello Mario, Alterio Vincenzo, Amodeo Pietro, et al. Metal Ion Substitution in the Catalytic Site Greatly Affects the Binding of Sulfhydryl-containing Compounds to Leucyl Aminopeptidase.. Biochemistry Mar 2006;45:3226-34
Abstract
Bovine lens leucyl aminopeptidase (blLAP), a homohexameric metallopeptidase preferring bulky and hydrophobic amino acids at the N-terminus of (di)peptides, contains two Zn(2+) ions per subunit that are essential for catalytic activity. They may be replaced by other divalent cations with different exchange kinetics. The protein readily exchangeable site (site 1) can be occupied by Zn(2+), Mn(2+), Mg(2+), or Co(2+), while the tight binding site (site 2) can be occupied by Zn(2+) or Co(2+). We recently reported that introduction of Mn(2+) into site 1 generates a novel activity of blLAP toward CysGly [Cappiello, M., et al. (2004) Biochem. J. 378, 35-44], which in contrast is not hydrolyzed by the (Zn/Zn) enzyme. This finding, while disclosing a potential specific role for blLAP in glutathione metabolism, raised a question about the features required for molecules to be a substrate for the enzyme. To clarify the interaction of the enzyme with sulfhydryl-containing derivatives, (Zn/Zn)- and (Mn/Zn)blLAP forms were prepared and functional-structural studies were undertaken. Thus, a kinetic analysis of various compounds with both enzyme forms was performed; the crystal structure of (Zn/Zn)blLAP in complex with the peptidomimetic derivative Zofenoprilat was determined, and a modeling study on the CysGly-(Zn/Zn)blLAP complex was carried out. This combined approach provided insight into the interaction of blLAP with sulfhydryl-containing derivatives, showing that the metal exchange in site 1 modulates binding to these molecules that may result in enzyme substrates or inhibitors, depending on the nature of the metal.
Mesh Headings (Keywords): Binding Sites, Catalytic Domain, Cations, Divalent, Crystallography, X-Ray, Enzyme Inhibitors, Hydrolases, Kinetics, Leucyl Aminopeptidase, Manganese, Models, Molecular, Structure-Activity Relationship, Substrate Specificity, Sulfhydryl Compounds, Zinc
Check for Full Text / PubMed Unique Identifier (PMID): 16519517
This abstract is part of PubMed, a service of the U.S. National Library of Medicine. PubMed includes more than 17 million citations from MEDLINE and other life science journals for biomedical articles. See Copyright and Disclaimers.
Linked medical terms appearing on this page are added by Healia to help readers find more information and are not part of the original PubMed document.
The data herein was last updated on July 8th, 2008 and may not reflect the most current and accurate data available from NLM.