Conformational change coupling the dimerization and activation of KSHV protease.

The mechanism of herpesviral protease activation upon dimerization was studied using two independent spectroscopic assays augmented by directed mutagenesis. Spectroscopic changes, attributable to dimer interface conformational plasticity, were observed upon dimerization of Kaposi's sarcoma-associated herpesvirus protease (KSHV Pr). KSHV Pr's dissociation constant of 585 +/- 135 nM at 37 degrees C was measured by a concentration-dependent, 100-fold increase in specific activity to a value of 0.