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

Simian immunodeficiency virus protease (SIV-PR) was produced in Escherichia coli with a recombinant expression system in which the mature enzyme autoprocessed from a precursor form. Recombinant SIV and HIV-1 (human immunodeficiency virus, type 1) proteases were purified from bacterial cell lysates by use of sequential steps of ammonium sulfate precipitation and size-exclusion and ion-exchange chromatography. The amino acid composition, amino-terminal sequence, and molecular weight (monomer) of the recombinant SIV-PR were in accord with that of the 99 amino acid polypeptide predicted from the SIVMac-PR nucleotide sequence. The active form of SIV-PR was shown to be dimeric by gel filtration chromatography. Inhibition by pepstatin A, time-dependent inactivation by 1,2-epoxy-3-(4-nitrophenoxy)propane, and pH rate profiles using oligopeptide substrates demonstrated that SIV-PR behaves as an aspartic protease. Recombinant HIV-1 Pr55gag precursor was processed in vitro by SIV-PR and HIV-1 PR with indistinguishable proteolytic patterns upon NaDodSO4-polyacrylamide gel electrophoresis. Oligopeptide substrates for HIV-1 PR were found to be suitable substrates for recombinant SIV-PR with the exception of a peptide containing the site identified for p66/p51 cleavage (Phe*Tyr) within HIV-1 reverse transcriptase (RT). Several synthetic peptide analogue inhibitors of HIV-1 PR were also potent inhibitors of SIV-PR, indicating that SIV infection in macaques and rhesus monkeys should be useful models for the preclinical evaluation of acquired immunodeficiency syndrome (AIDS) therapeutics targeted towards the virally encoded HIV-1 protease.
 ...
PMID:Purification and biochemical characterization of recombinant simian immunodeficiency virus protease and comparison to human immunodeficiency virus type 1 protease. 188 29

Mutations were introduced into the P2 and P1 positions of the junctions, (a) linking reverse transcriptase (RT) and integrase (IN) (-Leu*Phe-) and (b) between the p51 and RNase H domain (-Phe*Tyr-) within p66 of RT in the HIV-1 pol polyprotein. Processing by HIV proteinase (PR) in cis was monitored upon expression of these constructs in E. coli. Whereas the presence of Leu or Phe in P1 permitted rapid cleavage at either junction, substitution of a beta-branched (Ile) hydrophobic residue essentially abolished hydrolysis. By contrast, placement of a beta-branched (Val) residue in the P2 position flanking such -Hydrophobic*Hydrophobic- junctions resulted in effective cleavage of the scissile peptide bond. Gly in P2, however, abrogated cleavage. The significance of these findings in terms of PR specificity, polyprotein processing and the generation of homodimeric (p51/p51) RT for crystallisation purposes is discussed.
 ...
PMID:Mutating P2 and P1 residues at cleavage junctions in the HIV-1 pol polyprotein. Effects on hydrolysis by HIV-1 proteinase. 204 56

As part of a phase 1 trial of a candidate AIDS vaccine, blood specimens were collected from 168 healthy adult volunteers at minimal or no risk for becoming infected with human immunodeficiency virus type 1 (HIV-1). These specimens were screened for evidence of HIV-1 infection by enzyme immunoassay (EIA) and the Biotech/Du Pont Western blot (n = 168), culture (n = 122), and polymerase chain reaction assay (n = 20). None of the subjects had a positive test result by any of these assays, but 32% had indeterminate Western blot tests, most of which demonstrated a single band of low intensity. The most common bands were p24 (47%), p55 (34%), and p66 (36%); envelope bands were unusual (gp41, 2%; gp120, 2%). No serum specimen collected after 2-11 months from individuals with indeterminate Western blot results was positive by EIA or Western blot. There was 91% agreement in the test results of the first and second serum samples when the same lot of Western blot kit was used but only 36% agreement when different lots were used. The Biotech/Du Pont Western blot kit thus frequently yields indeterminate test results in the absence of HIV-1 infection, the reproducibility of which is subject to lot-to-lot variability.
 ...
PMID:Frequency of indeterminate western blot tests in healthy adults at low risk for human immunodeficiency virus infection. The NIAID AIDS Vaccine Clinical Trails Network. 223 Feb 70

The HIV immunoblot profiles of 700 HIV-antibody-positive sera were examined to determine the frequency of antibody reactivity with p66/p51, the reverse transcriptase of HIV. We report a remarkably high seroprevalence of antibodies to p66/p51, detected in 79% of the sera. Only gp41 is recognized more frequently in these assays. The level of anti-p66/p51 seroreactivity varies only slightly among the clinical stages of HIV infection.
 ...
PMID:High prevalence of serum antibodies to reverse transcriptase in HIV-1-infected individuals. 245 48

The reverse transcriptase of HIV-1 (AIDS virus) is characterized by the presence of two highly immunogenic proteins of 66 and 51 kD known to be enzymatically active as a complex p66/51. Using an activity gel procedure that allows identification of catalytic polypeptides in situ after PAGE in denaturing conditions, we visualized two major active bands of 66 and 51 kD of reverse transcriptase from highly purified preparations of HIV-1. We show that both p66 and p51 are enzymatically active. An additional active band was also associated with a 165 kD polypeptide, representing about 2-4% of total activity and possibly corresponding to the putative gag-pol precursor. In H9-infected cells the 66 kD active band became visible 70 hours after infection. These studies show that the two major forms of reverse transcriptase (66 and 51 kD) of HIV-1 are independently active and that a higher Mr form of 165 kD is also enzymatically active.
 ...
PMID:Enzymatically active forms of reverse transcriptase of the human immunodeficiency virus. 246 25

Recombinant HIV-1 reverse transcriptase (RT) was stably overproduced as a soluble protein in Escherichia coli using a double-plasmid expression system in which an RT precursor protein was expressed and processed in vivo by HIV-1 protease produced in trans. The RT thus produced consisted of an equimolar mixture of two polypeptides, p66 and p51, which were copurified to greater than 90% homogeneity and were found to share a common NH2 terminus as judged by sequence analysis of the polypeptide mixture. The observed sequence confirmed correct in vivo cleavage by protease at the protease-RT polyprotein junction to yield an NH2 terminus identical to that of genuine viral RT (M. M. Lightfoote et al. (1986) J. Virol. 60, 771-775; F. diMarzo Veronese et al. (1986) Science 231, 1289-1291). The bacterially expressed RT had a specific activity similar to that of viral RT and inhibition studies with phosphonoformate confirmed that it was indistinguishable from the viral enzyme with respect to sensitivity to this inhibitor. Polymerase activated gel analysis of the mixture indicated that p66 was associated with a higher level of RT activity than p51. RNase H activated gel analysis suggested that the purified preparation of recombinant RT was free of endogenous E. coli RNase H, and that the RNase H activity of RT was exclusively associated with the p66 polypeptide, supporting the hypothesis that the RNase H domain is located in the COOH-terminal region of the molecule.
 ...
PMID:Recombinant HIV-1 reverse transcriptase: purification, primary structure, and polymerase/ribonuclease H activities. 247 69

The virion cores of the replication competent type 1 human immunodeficiency virus (HIV-1), a retrovirus, contain and RNA genome associated with nucleocapsid (NC) and reverse transcriptase (RT p66/p51) molecules. In vitro reconstructions of these complexes with purified components show that NC is required for efficient annealing of the primer tRNALys,3. In the absence of NC, HIV-1 RT is unable to retrotranscribe the viral RNA template from the tRNA primer. We demonstrate that the HIV-1 RT p66/p51 specifically binds to its cognate primer tRNALys,3 even in the presence of a 100-fold molar excess of other tRNAs. Cross-linking analysis of this interaction locates the contact site to a region within the heavily modified anti-codon domain of tRNALys,3.
 ...
PMID:HIV-1 reverse transcriptase specifically interacts with the anticodon domain of its cognate primer tRNA. 247 43

The RNase H activity associated with recombinant p66/p51 HIV-1 reverse transcriptase (RT) has been analyzed in the absence of DNA synthesis by using homogeneous RNA.DNA substrates. The substrates consisted of SP6 runoff transcripts from a portion of the gag region of the HIV-1 genome hybridized to complementary single-stranded DNA from either an M13 subclone or a phagemid transcription vector subclone. The corresponding hybrids either carried a 5'-mismatch of seven nucleotides or were fully base-paired. Analysis of recombinant HIV-1 p66/p51 RT by an activated gel assay employing these substrates suggested that the RNase H activity was exclusively associated with the p66 polypeptide. Denaturing gel electrophoresis was used to analyze the oligonucleotide products generated by hydrolysis of the hybrids by HIV-1 RT, M-MuLV RT, and Escherichia coli RNase H. The significant difference in the time-dependent distribution of products of HIV-1 RT vs E. coli RNase H catalyzed cleavage of 5'-mismatched hybrids indicated that the preparation of recombinant HIV-1 RT was free of contaminating bacterial RNase H. Although the HIV-1 RT associated RNase H activity shares many of the general mechanistic features of other retroviral enzymes [Gerard, G. F. (1981) Biochemistry 20, 256-265], the appearance of unique intermediates and end products in the course of hydrolysis of 5'-mismatched and fully base-paired hybrids indicated a significant difference in the sequence dependence of the kinetics of RNase H cleavage by HIV-1 RT and M-MuLV RT.
 ...
PMID:Analysis of the ribonuclease H activity of HIV-1 reverse transcriptase using RNA.DNA hybrid substrates derived from the gag region of HIV-1. 248 1

A total of 56 sera from asymptomatic HIV-seropositive subjects and patients with symptomatic HIV infection were studied by immunoblotting for IgM, IgG and IgG subclass reactivity against cytomegalovirus structural polypeptides. The results showed a high percentage of IgM-positive sera in the asymptomatic patients, and IgM reactivity was particularly high against a polypeptide of intermediate molecular weight (p66). IgG reactivity was very high against the majority of viral structural polypeptides with the possible exceptions of p82 and p61, in all patients. Antibody to these polypeptides decreased with the increase in HIV-specific symptoms. No significant difference in the reactivity of IgG subclass to viral polypeptides was found among the different groups of subjects, except for a generalized increase in IgG subclass reactivity from asymptomatic to HIV-specific symptomatic patients.
 ...
PMID:Antibody reactivity to cytomegalovirus structural polypeptides in subclinical and clinical human immunodeficiency virus infections. 254 32

This report describes the isolation and characterization of a retrovirus of the HIV-2 group from a Ghanaian AIDS patient which has different restriction patterns from previously reported HIV-2 viruses. The virus was morphologically very similar to HIV-1 and HIV-2, and had Mg2+-dependent reverse transcriptase. Like previous HIV isolates, it induced severe cytopathic effects in CD4-positive human lymphoid cell lines. Its major proteins were shown to be gp110, p66, p55, p41, gp32, p30 and p26 by Western blot analysis. In dot-blot hybridization experiments, the virus hybridized with a HIV-2 DNA probe, but not with HIV-1 and SIVagm probes in stringent conditions. These data indicate that this Ghanaian virus is a HIV-2 group virus. However, in a Southern blot hybridization experiment, the restriction patterns of this virus, designated HIV-2 [GH-1], were quite different from those of previously reported HIV-2 viruses from West Africa isolated at the Pasteur Institute.
 ...
PMID:Isolation and characterization of HIV-2 from an AIDS patient in Ghana. 314 68


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>