Document Detail


Thimet oligopeptidase: site-directed mutagenesis disproves previous assumptions about the nature of the catalytic site.
MedLine Citation:
PMID:  9755850     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Zinc metallopeptidases that contain the His-Glu-Xaa-Xaa-His (HEXXH) motif generally have a third ligand of the metal ion that may be either a Glu residue (in clan MA) or a His residue (in clan MB) (Rawlings and Barrett (1995) Methods Enzymol. 248, 183-228). Thimet oligopeptidase has not yet been assigned to either clan, and both Glu and His residues have been proposed as the third ligand. We mutated candidate ligand residues in the recombinant enzyme and identified Glu, His and Asp residues that are important for catalytic activity and/or stability of the protein. However, neither of the Glu and His residues close to the HEXXH motif that have previously been suggested to be ligands is required for the binding of zinc. We conclude that thimet oligopeptidase is not a member of clan MA or clan MB and it is likely that the enzyme possesses a catalytic site and protein fold different from those identified in any metallopeptidase to date. The definitive identification of the third zinc ligand may well require the determination of the crystallographic structure of thimet oligopeptidase or one of its homologues.
Authors:
J M Chen; R A Stevens; P W Wray; N D Rawlings; A J Barrett
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  FEBS letters     Volume:  435     ISSN:  0014-5793     ISO Abbreviation:  FEBS Lett.     Publication Date:  1998 Sep 
Date Detail:
Created Date:  1998-10-05     Completed Date:  1998-10-05     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0155157     Medline TA:  FEBS Lett     Country:  NETHERLANDS    
Other Details:
Languages:  eng     Pagination:  16-20     Citation Subset:  IM    
Affiliation:
MRC Peptidase Laboratory, The Babraham Institute, Cambridge, UK. Jinq-May.Chen@bbsrc.ac.uk
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MeSH Terms
Descriptor/Qualifier:
Amino Acid Sequence
Animals
Binding Sites / genetics
Catalysis
Enzyme Activation / genetics
Gene Expression Regulation, Enzymologic
Glutamic Acid / genetics
Histidine / genetics
Ligands
Metalloendopeptidases / biosynthesis,  genetics*,  metabolism
Molecular Sequence Data
Mutagenesis, Site-Directed*
Rats
Recombinant Proteins / biosynthesis,  metabolism
Zinc / metabolism
Chemical
Reg. No./Substance:
0/Ligands; 0/Recombinant Proteins; 56-86-0/Glutamic Acid; 71-00-1/Histidine; 7440-66-6/Zinc; EC 3.4.24.-/Metalloendopeptidases; EC 3.4.24.15/thimet oligopeptidase

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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