Increasing the synthesis/hydrolysis ratio of aminoacylase 1 by site-directed mutagenesis

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DOIResolve DOI: http://doi.org/10.1016/j.biochi.2009.09.017
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TypeArticle
Journal titleBiochimie
Volume91
Issue1
Pages102109; # of pages: 8
SubjectAminoacylase; Pig kidney; Computer modeling; N-acyl-l-amino acids
AbstractAminoacylase-1 from pig kidney (pAcy1) catalyzes the highly stereoselective acylation of amino acids, a useful conversion for the preparation of optically pure N-acyl-l-amino acids. The kinetic of this thermodynamically controlled conversion is determined by maximal velocities for synthesis (VmS) and hydrolysis (VmH) of the N-acyl-l-amino acid. To investigate which parameter affects maximal velocities, we focused on the proton acceptor potential of the catalytic base, E146, and studied the influence of the active site architecture on its contribution to the pKa of residue E146. The modeled structure of pAcy1 identified residue D346 as having the strongest impact on the electrostatic features of the catalytic base. Substitutions of D346 generally decreased enzymatic activities but also altered both the pH-dependency of hydrolytic activity and the VmS/VmH ratio of pAcy1. A reduced theoretical pKa value and a lowered experimental pH optimum of hydrolytic rates for the D346A mutant were associated with a 9-fold increase in VmS/VmH. This supports the importance of electrostatic contributions of D346 to the acid-base properties of E146 and demonstrates for the first time the possibility of engineering the VmS/VmH ratio of pAcy1.
Publication date
LanguageEnglish
AffiliationNational Research Council Canada (NRC-CNRC); NRC Biotechnology Research Institute
Peer reviewedYes
NRC number50656
NPARC number16526903
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Record identifier63230c1b-0dfe-4833-9e37-76ac0696068e
Record created2010-12-14
Record modified2016-05-09
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