Three-dimensional structure of human cytomegalovirus protease

The three dimensional structure of human cytomegalovirus protease at 2.27 resolution reveals an unique fold and a catalytic method for cleavage. The monomer fold of the enzyme has a seven-stranded beta-barrel encircled by a chain of helixes that form the carboxy terminus of the molecule. The histidine residues at positions 63 and 157 activate the serine nucleophile at position 132. Dimerization in the molecule imparts specificity and recognition in the substrate binding activity.