title: An angiotensin I-converting enzyme mutation (Y465D) causes a dramatic increase in blood ACE via accelerated ACE shedding.
abstract: BACKGROUND
  Angiotensin I-converting enzyme (ACE) metabolizes a range of peptidic substrates and plays a key role in blood pressure regulation and vascular remodeling. Thus, elevated ACE levels may be associated with an increased risk for different cardiovascular or respiratory diseases. Previously, a striking familial elevation in blood ACE was explained by mutations in the ACE juxtamembrane region that enhanced the cleavage-secretion process. Recently, we found a family whose affected members had a 6-fold increase in blood ACE and a Tyr465Asp (Y465D) substitution, distal to the stalk region, in the N domain of ACE.
  
  
  RESULTS
  HEK and CHO cells expressing mutant (Tyr465Asp) ACE demonstrate a 3- and 8-fold increase, respectively, in the rate of ACE shedding compared to wild-type ACE. Conformational fingerprinting of mutant ACE demonstrated dramatic changes in ACE conformation in several different epitopes of ACE. Cell ELISA carried out on CHO-ACE cells also demonstrated significant changes in local ACE conformation, particularly proximal to the stalk region. However, the cleavage site of the mutant ACE--between Arg1203 and Ser1204--was the same as that of WT ACE. The Y465D substitution is localized in the interface of the N-domain dimer (from the crystal structure) and abolishes a hydrogen bond between Tyr465 in one monomer and Asp462 in another.
  
  
  CONCLUSIONS
  The Y465D substitution results in dramatic increase in the rate of ACE shedding and is associated with significant local conformational changes in ACE. These changes could result in increased ACE dimerization and accessibility of the stalk region or the entire sACE, thus increasing the rate of cleavage by the putative ACE secretase (sheddase).
authors: Department of Anesthesiology, University of Illinois at Chicago, Chicago, Illinois, United States of America. danilov@uic.edu
authors: Sergei M
authors: SM
authors: Danilov
authors: Kerry
authors: K
authors: Gordon
authors: Andrew B
authors: AB
authors: Nesterovitch
authors: Heinrich
authors: H
authors: Lünsdorf
authors: Zhenlong
authors: Z
authors: Chen
authors: Maricela
authors: M
authors: Castellon
authors: Isolda A
authors: IA
authors: Popova
authors: Sergey
authors: S
authors: Kalinin
authors: Emma
authors: E
authors: Mendonca
authors: Pavel A
authors: PA
authors: Petukhov
authors: David E
authors: DE
authors: Schwartz
authors: Richard D
authors: RD
authors: Minshall
authors: Edward D
authors: ED
authors: Sturrock
mesh_terms: D000818:Animals; D001665:Binding Sites; D016466:CHO Cells; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism*; D019295:Computational Biology; D006224:Cricetinae; D003412:Cricetulus; D004252:DNA Mutational Analysis; D010450:Endopeptidases / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D050505:Mutant Proteins / Q000097:blood* / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D007703:Peptidyl-Dipeptidase A / Q000097:blood* / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D055503:Protein Multimerization / Q000187:drug effects; D017434:Protein Structure, Tertiary; D059748:Proteolysis / Q000187:drug effects
chemical_list: D050505:Mutant Proteins; D010450:Endopeptidases; D007703:Peptidyl-Dipeptidase A; C077675:angiotensin converting enzyme secretase