A novel angiotensin I-converting enzyme mutation (S333W) impairs N-domain enzymatic cleavage of the anti-fibrotic peptide, AcSDKP.

TitleA novel angiotensin I-converting enzyme mutation (S333W) impairs N-domain enzymatic cleavage of the anti-fibrotic peptide, AcSDKP.
Publication TypeJournal Article
Year of Publication2014
AuthorsDanilov SM, Wade MS, Schwager SL, Douglas RG, Nesterovitch AB, Popova IA, Hogarth KD, Bhardwaj N, Schwartz DE, Sturrock ED, Garcia JGN
JournalPLoS One
Volume9
Issue2
Paginatione88001
Date Published2014
ISSN Number1932-6203
KeywordsAmino Acid Sequence, Animals, Cell Line, CHO Cells, Cricetulus, Fibrosis, Humans, Kinetics, Molecular Sequence Data, Mutation, Oligopeptides, Peptides, Peptidyl-Dipeptidase A, Sequence Alignment
Abstract

<p><b>BACKGROUND: </b>Angiotensin I-converting enzyme (ACE) has two functional N- and C-domain active centers that display differences in the metabolism of biologically-active peptides including the hemoregulatory tetrapeptide, Ac-SDKP, hydrolysed preferentially by the N domain active center. Elevated Ac-SDKP concentrations are associated with reduced tissue fibrosis.</p><p><b>RESULTS: </b>We identified a patient of African descent exhibiting unusual blood ACE kinetics with reduced relative hydrolysis of two synthetic ACE substrates (ZPHL/HHL ratio) suggestive of the ACE N domain center inactivation. Inhibition of blood ACE activity by anti-catalytic mAbs and ACE inhibitors and conformational fingerprint of blood ACE suggested overall conformational changes in the ACE molecule and sequencing identified Ser333Trp substitution in the N domain of ACE. In silico analysis demonstrated S333W localized in the S1 pocket of the active site of the N domain with the bulky Trp adversely affecting binding of ACE substrates due to steric hindrance. Expression of mutant ACE (S333W) in CHO cells confirmed altered kinetic properties of mutant ACE and conformational changes in the N domain. Further, the S333W mutant displayed decreased ability (5-fold) to cleave the physiological substrate AcSDKP compared to wild-type ACE.</p><p><b>CONCLUSIONS AND SIGNIFICANCE: </b>A novel Ser333Trp ACE mutation results in dramatic changes in ACE kinetic properties and lowered clearance of Ac-SDKP. Individuals with this mutation (likely with significantly increased levels of the hemoregulatory tetrapeptide in blood and tissues), may confer protection against fibrosis.</p>

DOI10.1371/journal.pone.0088001
Alternate JournalPLoS ONE
PubMed ID24505347
PubMed Central IDPMC3913711