Gly216 in the active site of the broadly specific MA190 mutant of alpha-lytic protease has been found to be remarkably tolerant of amino acid substitutions. Side-chains as large as Trp can be accommodated within the substrate-binding pocket without abolishing catalysis, and have major effects upon the substrate specificity of the enzyme ...
Gly216 in the active site of the broadly specific MA190 mutant of alpha-lytic protease has been found to be remarkably tolerant of amino acid substitutions. Side-chains as large as Trp can be accommodated within the substrate-binding pocket without abolishing catalysis, and have major effects upon the substrate specificity of the enzyme. Kinetic characterization of eleven enzymatically active mutants against a panel of eight substrates clearly revealed the functional consequences of the substitutions at position 216. To understand better the structural basis for their altered specificity, the GA216 + MA190 and GL216 + MA190 mutants have been crystallized both with and without a representative series of peptide boronic acid transition-state analog inhibitors. An empirical description and non-parametric statistical analysis of structural variation among these enzyme: inhibitor complexes is presented. The roles of active site plasticity and dynamics in alpha-lytic protease function and substrate preference are also addressed. The results strongly suggest that substrate specificity determination in alpha-lytic protease is a distributed property of the active site and substrate molecule.
Related Citations:
Structural Basis for Broad Specificity in Alpha-Lytic Protease Bone, R., Fujushige, A., Kettner, C.A., Agard, D.A. (1991) Biochemistry 30: 10388
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Refined Structure of Alpha-Lytic Protease at 1.7 Angstroms Resolution. Analysis of Hydrogen Bonding and Solvent Structure Fujinaga, M., Delbaere, L.T.J., Brayer, G.D., James, M.N.G. (1985) J Mol Biol 184: 479
Molecular Structure of the Alpha-Lytic Protease from Myxobacter 495 at 2.8 Angstroms Resolution Brayer, G.D., Delbaere, L.T.J., James, M.N.G. (1979) J Mol Biol 131: 743
Organizational Affiliation:
Howard Hughes Medical Institute, University of California, San Francisco 94143-0448, USA.
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