Document Detail


Mixed dimers of insulin-degrading enzyme reveal a cis activation mechanism.
MedLine Citation:
PMID:  21343292     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Insulin-degrading enzyme (IDE) exists primarily as a dimer being unique among the zinc metalloproteases in that it exhibits allosteric kinetics with small synthetic peptide substrates. In addition the IDE reaction rate is increased by small peptides that bind to a distal site within the substrate binding site. We have generated mixed dimers of IDE in which one or both subunits contain mutations that affect activity. The mutation Y609F in the distal part of the substrate binding site of the active subunit blocks allosteric activation regardless of the activity of the other subunit. This effect shows that substrate or small peptide activation occurs through a cis effect. A mixed dimer composed of one wild-type subunit and the other subunit containing a mutation that neither permits substrate binding nor catalysis (H112Q) exhibits the same turnover number per active subunit as wild-type IDE. In contrast, a mixed dimer in which one subunit contains the wild-type sequence and the other contains a mutation that permits substrate binding, but not catalysis (E111F), exhibits a decrease in turnover number. This indicates a negative trans effect of substrate binding at the active site. On the other hand, activation in trans is observed with extended substrates that occupy both the active and distal sites. Comparison of the binding of an amyloid β peptide analog to wild-type IDE and to the Y609F mutant showed no difference in affinity, indicating that Y609 does not play a significant role in substrate binding at the distal site.
Authors:
Eun Suk Song; David W Rodgers; Louis B Hersh
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural     Date:  2011-02-22
Journal Detail:
Title:  The Journal of biological chemistry     Volume:  286     ISSN:  1083-351X     ISO Abbreviation:  J. Biol. Chem.     Publication Date:  2011 Apr 
Date Detail:
Created Date:  2011-04-18     Completed Date:  2011-06-28     Revised Date:  2013-06-30    
Medline Journal Info:
Nlm Unique ID:  2985121R     Medline TA:  J Biol Chem     Country:  United States    
Other Details:
Languages:  eng     Pagination:  13852-8     Citation Subset:  IM    
Affiliation:
Department of Molecular and Cellular Biochemistry and the Center for Structural Biology, University of Kentucky, Lexington, Kentucky 40536, USA.
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MeSH Terms
Descriptor/Qualifier:
Amyloid beta-Peptides / chemistry
Animals
Bradykinin / chemistry
Catalysis
Catalytic Domain
Circular Dichroism
Dimerization
Dynorphins / chemistry
Endorphins / chemistry
Humans
Insulin / chemistry*,  metabolism*
Kinetics
Molecular Weight
Mutation
Peptides / chemistry
Substrate Specificity
Grant Support
ID/Acronym/Agency:
DA02243/DA/NIDA NIH HHS; NS38041/NS/NINDS NIH HHS; P20 RR020171/RR/NCRR NIH HHS
Chemical
Reg. No./Substance:
0/Amyloid beta-Peptides; 0/Endorphins; 0/Insulin; 0/Peptides; 58-82-2/Bradykinin; 74913-18-1/Dynorphins; 83335-41-5/rimorphin
Comments/Corrections

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


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