Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0019693 (HIV)
 170,526 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The HIV-1 protease is becoming one of the most important proteins in medicine. It is perhaps the most attractive target for development of an anti-HIV-1 therapeutic drug. Given its pre-eminent position in biomedical research, many aspects of the protease are currently coming under close scrutiny. Protease is available from recombinant sources, and numerous structures of the enzyme (with and without bound inhibitors) have now been determined by crystallographic methods, enabling the full utilization of mutational analysis in the study of protease function. In addition, the selection of HIV-1 mutants with reduced sensitivity to protease inhibitors is further complementing research on this enzyme.
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PMID:Characterization of HIV-1 protease mutants: random, directed, selected. 776 74

Upon in vitro processing of the recombinant HIV-1/gag p24 protein, expressed in Escherichia coli as a fusion protein, by HIV-1 protease, a cleavage site within the staphylococcal protein A fusion partner was found. N-terminal sequencing of the protein A fragments showed that HIV-1 protease cleavage occurred between phenylalanine-235 and tyrosine-236 within the sequence Gln-Asn-Ala-Phe/Tyr-Glu-Ile-Leu (QNAF/YEIL) in the IgG-binding domain C of the protein A encoded by the pRIT2T fusion gene vector (Pharmacia). Results presented here have proven that the protease-sensitive site is viable in vitro on the protein A alone and other chimeric protein, protein A/beta-galactosidase. A possible significance of this phenomenon in biotechnology work is discussed.
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PMID:Staphylococcal protein A is a novel heterologous substrate for the HIV-1 protease. 776 14

A series of novel pseudo-symmetrical and unsymmetrical inhibitors based on the backbone modification of a peptidomimetic were synthesized and found to be highly potent inhibitors of the HIV-1 protease (IC50 = 2.9 to < 0.5 nM). These compounds also possess good antiviral activity in vitro as measured by inhibition of the cytopathic effect of HIV-1(3B) in MT-4 lymphocytes. Importantly, some of these compounds also have good oral bioavailabilities in rats (F = 30.6% to 100%). One of these compounds 4C, also has good oral bioavailability in beagle dogs and cynomolgus monkeys.
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PMID:Potent inhibitors of the HIV-1 protease with good oral bioavailabilities. 777 82

Recombinant purified Nef protein of HIV-1, as well as Nef protein derived from extracts of permanently HIV-1 infected glioblastoma cells and monocytes, are specifically cleaved by the HIV-1 protease. Nef cleavage products in cellular extracts treated with protease showed identical molecular weights as those obtained by digestion of purified Nef with recombinant HIV-1 protease. Since cellular extracts were prepared by detergent and mechanical lysis it cannot be excluded that physiological cytoplasmic conditions were altered. The lack of Nef cleavage by endogenous HIV-1 protease in infected cells might be due to low concentrations of viral protease and the presence of Gag precursor molecules as natural substrate. Using a panel of monoclonal antibodies two cleavage fragments of 19 kDa and 8 kDa were defined. The cleavage site was located by microsequencing between amino acid 57 and 58 (AW*LEAQEEEEVGF). The conserved cleavage motif within HIV-1 Nef suggests a potential biological function of Nef processing.
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PMID:Cleavage of recombinant and cell derived human immunodeficiency virus 1 (HIV-1) Nef protein by HIV-1 protease. 783 26

Hydrogen bonding plays an important role in the stabilization of complexes between HIV-1 protease (HIV-1 PR) and its inhibitors. The adequate treatment of the protease active site protonation state is important for accurate molecular simulations of the protonation state is important for accurate molecular simulations of the protease-inhibitor complexes. We have applied the free energy simulation/thermodynamic cycle approach to evaluate the relative binding affinities of the S vs R isomers of the U85548E inhibitor of the protease. Several mono- and diprotonation states of the catalytic aspartic acid residues of the protease active site were considered in the course of molecular simulations. The calculated difference in binding free energy of the S vs R isomers strongly depended on the location of proton(s), but in all cases the binding free energy of the S inhibitor was higher. On the basis of our calculations, we propose that in the HIV-1 PR-inhibitor complex only one catalytic aspartic acid residue is protonated and that the binding free energy of the S isomer is ca. 2.8 kcal/mol higher than that of the R isomer. The accuracy of these predictions shall be evaluated when binding affinities of both isomers become available.
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PMID:Relative binding free energies of peptide inhibitors of HIV-1 protease: the influence of the active site protonation state. 783 38

HIV PROTEINASE INHIBITORS: The HIV proteinase enzyme has been identified as a potential target for antiretroviral therapy, as inhibition of this enzyme leads to the generation of immature, non-infectious virions. There are several proteinase inhibitors in development; the first to enter clinical trials was saquinavir. DEVELOPMENT OF SAQUINAVIR: Saquinavir, a transition-stage analogue of an HIV proteinase cleavage site, was developed using computer-led rational design techniques. It is a highly specific inhibitor of HIV-1 and -2 proteinases, with antiviral activity at concentrations 1000-fold less than those causing cytotoxicity. EUROPEAN CLINICAL EXPERIENCE WITH SAQUINAVIR: Three European clinical studies involving 202 patients have been conducted with saquinavir at doses of 25, 75, 200 and 600 mg three times a day. Two studies were dose-ranging monotherapy trials, one in asymptomatic or mildly symptomatic patients not previously treated with zidovudine, the other in patients with advanced HIV infection who had been treated with zidovudine. The third study was a combination therapy trial with zidovudine in previously untreated patients with advanced infection. Saquinavir was well tolerated either alone or in combination with zidovudine. In the monotherapy studies, CD4 cell counts and estimates of viral load showed the best results with the 600-mg dose. The combination of saquinavir and zidovudine resulted in higher and more sustained increases in CD4 cell counts than with either drug alone. The CD4 cell counts favoured saquinavir at 200 and 600 mg in combination with zidovudine, although plasma viraemia and the RNA polymerase chain reaction indicated that the 600-mg dose (in combination) produced better responses.
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PMID:HIV therapy advances. Update on a proteinase inhibitor. 784 Sep 13

Several new analogues of the novel anti-HIV agent cosalane have been synthesized and evaluated as inhibitors of HIV-1 integrase and protease, HIV-1 replication, HIV-1 and HIV-2 cytopathicity, HIV-1- and HIV-2-mediated syncytium formation, and cytopathicity of a variety of human pathogenic viruses. The congeners displayed enhanced potencies relative to cosalane itself as inhibitors of HIV-1 integrase and protease. The two most potent analogues against HIV-1 integrase displayed IC50 values of 2.2 microM, while the three most potent compounds against HIV-1 protease had IC50 values in the 0.35-0.39 microM range. In addition to its activity against HIV-1 and HIV-2 cytopathicity, cosalane inhibited the cytopathic effects of herpes simplex virus-1, herpes simplex virus-2, and human cytomegalovirus at concentrations that were well below the cytotoxic concentrations. Potentially useful antiviral activities were also revealed for some of the new cosalane congeners against influenza virus, Junin virus, and Tacaribe virus.
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PMID:Cosalane analogues with enhanced potencies as inhibitors of HIV-1 protease and integrase. 785 37

This chapter has focused on the application of molecular dynamics computer simulations and related molecular modeling techniques to the study of HIV protease structure and structure-function relationships. The abundance of crystallographic data provides ample experimental quantities (average structures, temperature factors, and hydrogen bond topography) to validate the computational techniques employed. Furthermore, these studies provide insight into the structure and functional energetics of HIV-1 protease that would be difficult or impossible to study experimentally. This chapter covers studies that investigate correlated motion between and within subunits of the protease, mutants of the protease that disrupt the tertiary structure and dimer formation, and studies of HIV-1 protease-inhibitor complexes that rationalize both the protonation state of the active site and the observed binding strength of these complexes. These studies demonstrate that MD is capable of contributing to our understanding of structure-function relationships and may aid in the design of potential therapeutics.
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PMID:Probing structure-function relationships in human immunodeficiency virus type 1 protease via molecular dynamics simulation. 785 78

Here we have investigated if human immunodeficiency virus type 1 (HIV-1) protease expressed in trans can interfere with production of infectious HIV-1 particles. Protease produced from a Tat and Rev inducible expression plasmid specifically cleaved HIV-1 p55Gag in a dose-dependent manner. Coexpression of protease and an infectious HIV-1 proviral clone resulted in increased intracellular cleavage of p55Gag. As a consequence, virus production and virus infectivity was significantly reduced. These results suggest that overexpression of HIV-1 protease in HIV-1-infected cells is a powerful way to inhibit production of infectious virions.
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PMID:Overexpression of human immunodeficiency virus type 1 protease increases intracellular cleavage of Gag and reduces virus infectivity. 785 98

(2R,4S,5S,1'S)-2-Phenylmethyl-4-hydroxy-5-(tert-butoxycarbonyl) amino-6-phenylhexanoyl-N-(1'-imidazo-2-yl)-2'-methylpropanamide (compound 2) is a tripeptide analogue inhibitor of HIV-1 protease in which a C-terminal imidazole substituent constitutes an isoelectronic, structural mimic of a carboxamide group. Compound 2 is a potent inhibitor of the protease (K(i) = 18 nM) and inhibits HIV-1 acute infectivity of CD4+ T-lymphocytes (IC50 = 570 nM). Crystallographic analysis of an HIV-1 protease-compound 2 complex demonstrates that the nitrogen atoms of the imidazole ring assume the same hydrogen-bonding interactions with the protease as amide linkages in other peptide analogue inhibitors. The sole substitution of the C-terminal carboxamide of a hydroxyethylene-containing tripeptide analogue with an imidazole group imparts greatly improved pharmacokinetic and oral bioavailability properties on the compound compared to its carboxamide-containing homologue (compound 1). While the oral bioavailability of compound 1 in rats was negligible, compound 2 displayed oral bioavailabilities of 30% and 14%, respectively, in rats and monkeys.
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PMID:An orally bioavailable HIV-1 protease inhibitor containing an imidazole-derived peptide bond replacement: crystallographic and pharmacokinetic analysis. 791 83


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