Alternating arginine-modulated substrate specificity in an engineered tyrosine aminotransferase.Malashkevich, V.N., Onuffer, J.J., Kirsch, J.F., Jansonius, J.N.
(1995) Nat Struct Biol 2: 548-553
- PubMed: 7664122
- DOI: https://doi.org/10.1038/nsb0795-548
- Primary Citation of Related Structures:
1AHE, 1AHF, 1AHG, 1AHX, 1AHY
- PubMed Abstract:
Mutation of six residues of Escherichia coli aspartate aminotransferase results in substantial acquisition of the transamination properties of tyrosine amino-transferase without loss of aspartate transaminase activity. X-ray crystallographic analysis of key inhibitor complexes of the hexamutant reveals the structural basis for this substrate selectivity. It appears that tyrosine aminotransferase achieves nearly equal affinities for a wide range of amino acids by an unusual conformational switch. An active-site arginine residue either shifts its position to electrostatically interact with charged substrates or moves aside to allow access of aromatic ligands.
Department of Structural Biology, University of Basel, Switzerland.