1yoo
From Proteopedia
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ASPARTATE AMINOTRANSFERASE MUTANT ATB17 WITH ISOVALERIC ACID
Overview
Directed evolution was used to change the substrate specificity of, aspartate aminotransferase. A mutant enzyme with 17 amino acid, substitutions was generated that shows a 2.1 x 10(6)-fold increase in the, catalytic efficiency (kcat/Km) for a non-native substrate, valine. The, absorption spectrum of the bound coenzyme, pyridoxal 5'-phosphate, is also, changed significantly by the mutations. Interestingly, only one of the 17, residues appears to be able to contact the substrate, and none of them, interact with the coenzyme. The three-dimensional structure of the mutant, enzyme complexed with a valine analog, isovalerate (determined to 2.4-A, resolution by x-ray crystallography), provides insights into how the, mutations affect substrate binding. The active site is remodeled; the, subunit interface is altered, and the enzyme domain that encloses the, substrate is shifted by the mutations. The present results demonstrate, clearly the importance of the cumulative effects of residues remote from, the active site and represent a new line of approach to the redesign of, enzyme activity.
About this Structure
1YOO is a Single protein structure of sequence from Escherichia coli with PLP and IVA as ligands. Active as Aspartate transaminase, with EC number 2.6.1.1 Full crystallographic information is available from OCA.
Reference
Redesigning the substrate specificity of an enzyme by cumulative effects of the mutations of non-active site residues., Oue S, Okamoto A, Yano T, Kagamiyama H, J Biol Chem. 1999 Jan 22;274(4):2344-9. PMID:9891001
Page seeded by OCA on Wed Nov 21 06:57:09 2007
