MUTAGENESIS OF CONSERVED RESIDUES OF THE ADENOVIRUS PROTEASE

Based on the alignment of 12 adenovirus protease sequences, we have id entified eleven conserved residues for mutagenesis. Eight of these, E5 , D26, N44, E71, D77, D102, N144, and N170, are potential candidates f or the third residue of the active site triad. N44, E71, N144, and N17 0 proved to be essential for enzyme activity. Glutamic acid 71 was pro posed for the active site. Mutation of the three conserved cysteines s uggested that C122 is the active nucleophile, C104 is the target for a ctivation by peptide pVlc, and C126 is dispensable. Rescue of enzyme a ctivity of the C104G mutant by pVlc suggested that disulfide bond form ation between the peptide and the protease may not be absolutely essen tial for stimulation of enzyme activity. (C) 1996 Academic Press, Inc.