Graber, R; Kasper, P; Malashkevich, V N; Sandmeier, E; Berger, P; Gehring, H; Jansonius, J N; Christen, P (1995). Changing the reaction specificity of a pyridoxal-5'-phosphate-dependent enzyme. FEBS Journal, 232(2):686-690.
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The electron distribution in the coenzyme-substrate adduct of aspartate aminotransferase was changed by replacing active-site Arg386 with alanine and introducing a new arginine residue nearby. [Y225R, R386A]Aspartate aminotransferase decarboxylates L-aspartate to L-alanine (kcat = 0.04 s-1), while its transaminase activity towards dicarboxylic amino acids is decreased by three orders of magnitude (kcat = 0.19 s-1). Molecular-dynamics simulations based on the crystal structure of the mutant enzyme suggest that a new hydrogen bond to the imine N atom of the pyridoxal-5'-phosphate- aspartate adduct and an altered electrostatic potential around its beta-carboxylate group underlie the 650,000-fold increase in the ratio of beta-decarboxylase/transaminase activity.
|Item Type:||Journal Article, refereed|
|Communities & Collections:||04 Faculty of Medicine > Department of Biochemistry
07 Faculty of Science > Department of Biochemistry
|Dewey Decimal Classification:||570 Life sciences; biology|
|Date:||1 September 1995|
|Deposited On:||11 Feb 2008 12:20|
|Last Modified:||28 Nov 2013 00:37|
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