| Knowledge of the structure-function relationships in b-glucosidase Zm-p60.1 is necessary for understanding its specificity and catalytic activity, and for rational engineering of its catalytic properties. Our previous experiments indicated an important role for cysteine residues in catalytic activity, and structural stability of Zm-p60.1. A combination of molecular and biochemical techniques is employed to assign function to individual cysteine residues in Zm-p60.1. Site-directed mutagenesis is used to replace cysteine residues by specific amino acids. Analysis of changed catalytic and structural properties of the enzyme will allow us to draw conclusions about the role of individual cysteine residues in activity and architecture of the enzyme. In mutants which lose activity we will search, by random mutagenesis, for second-site mutations restoring the enzyme activity. Thereby we will gain novel information on plasticity of the enzyme structure. |
