Function of active-site lysines of ribulose bisphosphate carboxylase/oxygenase

As one facet of elucidating the mechanism of ribulose-P/sub 2/ carboxylase, we have focused on active-site characterization with affinity labels. This report describes the determination of the pK/sub a/ values of two lysine residues thought to be at the active site, based on the pH-dependencies of chemical modification, determination of their proximity based on covalent cross-linking with bifunctional reagents, and determination of the consequences on catalytic functionality of their selective replacement with other amino acids by site-directed mutagenesis. 14 refs., 1 fig.