Lack of stereospecificity in the binding of the P2 amino acid of ritonavir to HIV protease

Abstract The biological and pharmacokinetic properties of the HIV protease inhibitor ritonavir and its D-valinyl diastereomer, A-117673, were found to be indistinguishable. The X-ray crystal structure of the A-117673/HIV protease complex demonstrated similar binding modes for the two inhibitors, with a ca 1 A difference in the backbone that allows the valine side chain of both compounds to project into the S2 subsite of the enzyme.