We designed, synthesized, and identified UIC-94017 (TMC114), a novel nonpeptidic human immunodeficiency virus type 1 (HIV-1) protease inhibitor (PI) containing a 3(R),3a(S),6a(R)-bis-tetrahydrofuranylurethane (bis-THF) and a sulfonamide isostere which is extremely potent against laboratory HIV-1 strains and primary clinical isolates (50% inhibitory concentration [IC 50

Saquinavir (SQV), the first antiviral HIV-1 protease (PR) inhibitor approved for AIDS therapy, has been studied in complexes with PR and the variants PR(I) (84V) and PR(V) (82A) containing the single mutations I84V and V82A that provide resistance to all the clinical inhibitors. Atomic resolution crystal structures (0.97-1.25 A) of the SQV complexes were analyzed in comparison to the protease complexes with darunavir, a new drug that targets resistant HIV, in order to understand the molecular basis of drug resistance. PR(I) (84V) and PR(V) (82A) complexes were obtained in both the space groups P2(1)2(1)2 and P2(1)2(1)2(1), which provided experimental limits for the conformational flexibility. The SQV interactions with PR were very similar in the mutant complexes, consistent with the similar inhibition constants. The mutation from bigger to smaller amino acids allows more space to accommodate the large group at P1' of SQV, unlike the reduced interactions observed in darunavir complexes. The residues 79-82 have adjusted to accommodate the large hydrophobic groups of SQV, suggesting that these residues are intrinsically flexible and their conformation depends more on the nature of the inhibitor than on the mutations in this region. This analysis will assist with development of more effective antiviral inhibitors.

A healthier HAART: We report the design, synthesis, biological evaluation, and X‐ray crystallographic analysis of a new class of HIV‐1 protease inhibitors. Compound 4 proved to be an extremely potent inhibitor toward various multidrug‐resistant HIV‐1 variants, representing a near 10‐fold improvement over darunavir (DRV). Compound 4 also blocked protease dimerization with at least 10‐fold greater potency than DRV.

The crystal structures of the wild-type HIV-1 protease (PR) and the two resistant variants, PR V82A and PR L90M , have been determined in complex with the antiviral drug, indinavir, to gain insight into the molecular basis of drug resistance. V82A and L90M correspond to an active site mutation and nonactive site mutation, respectively. The inhibition (K i ) of PR V82A and PR L90M was 3.3-and 0.16-fold, respectively, relative to the value for PR. They showed only a modest decrease, of 10-15%, in their k cat /K m values relative to PR. The crystal structures were refined to resolutions of 1.25-1.4 Å to reveal critical features associated with inhibitor resistance. PR V82A showed local changes in residues 81-82 at the site of the mutation, while PR L90M showed local changes near Met90 and an additional interaction with indinavir. These structural differences concur with the kinetic data.

We designed, synthesized, and identified GRL-98065, a novel nonpeptidic human immunodeficiency virus type 1 (HIV-1) protease inhibitor (PI) containing the structure-based designed privileged cyclic ether-derived nonpeptide P2 ligand, 3(R),3a(S),6a(R)-bis-tetrahydrofuranylurethane (bis-THF), and a sulfonamide isostere, which is highly potent against laboratory HIV-1 strains and primary clinical isolates (50% effective concen-