Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.30.2 (endonuclease)
 18,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The biochemical mechanisms underlying blood lymphoid cell genome destabilization in patients with HIV infection have been analyzed. Lymphocytes from HIV patients are characterized by increasing intensity of free radical oxidation together with activation of the xanthine oxidase D-form conversion into the O-form, enhanced activity of UV-endonuclease, and intensification of prooxidant-induced proteolysis. These changes increasing with the progress of the disease with a maximum at the AIDS stage form a metabolic basis for labilization of the lymph cell genome. The degree of biochemical manifestations of genome instability (levels of chromatin degradation products and intensity of formation of one-filament nicks of DNA) increase in the dynamics of HIV-infection. The data obtained are discussed in terms of the author's conception on the origin of AIDS from retroposons (retrotransposons?). A hypothesis is postulated on accumulation of autonomous genetic information on the basis of genome labilization under the influence of genotoxic factors. Clinico-biochemical data on the appearance of HIV proteins (p17, p24) in the blood of patients (previously negative for all HIV markers) in the presence of transfusions of HIV-negative blood and UV-irradiation of the autoblood are also discussed from this standpoint.
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PMID:[Genomic instability and AIDS]. 133 9

The gag and pol genes of the human immunodeficiency virus type 1 (HIV-1) (ref. 1) are translated as two polyproteins, Pr55gag and Pr160gag-pol (refs 2-6), which are subsequently cleaved by the action of a virus-encoded protease into the four structural gag proteins of the virion core (p17, p24, p7 and p6) and the pol-encoded enzymes essential for retrovirus replication (protease, reverse transcriptase, ribonuclease H, and endonuclease). Mutational inactivation of the proteases of HIV-1 and other retroviruses results in immature, non-infectious virions, indicating that exogenous inhibition of the protease may represent an attractive approach to anti-AIDS therapy. Here we demonstrate that synthetic peptide analogues, which are potent inhibitors of purified HIV-1 protease, inhibit the processing of the viral polyproteins in cultures of HIV-1-infected T lymphocytes and attenuate viral infectivity.
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PMID:Inhibition of HIV-1 protease in infected T-lymphocytes by synthetic peptide analogues. 168 46

Mutations were introduced by recombinant DNA techniques into 9 genes of an infectious molecular clone of human immunodeficiency virus type 1. The 24 mutants generated were characterized biochemically and biologically by transfection and infection experiments. None of the mutants which have mutations in gag (p17, p24, and p15 regions), pol (protease, reverse transcriptase, and endonuclease domains), env (gp120 region), tat, or rev were infectious, whereas vif, vpr, vpu, some of env (gp41) and nef mutants could grow in human CD4+ cells to various degrees. Of the non-infectious mutants, only endonuclease (pol) and gp41 mutants exhibited normal phenotypes with respect to the production of functional reverse transcriptase, the expression of gag, pol, and env proteins, and the generation of progeny virions, when examined in transient assays. All infectious mutants killed the CD4+ cells with the exception of a mutant carrying a defect in the vif gene.
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PMID:Generation and characterization of the human immunodeficiency virus type 1 mutants. 170 90

In order to characterize novel human immunodeficiency virus type 1 (HIV-1) continuous epitopes, we designed a simple method, based on recombinant DNA, providing a complete set of peptides derived from HIV-1. A library (4 x 10(4) clones) was first constructed in a new expression/secretion vector, using as inserts small fragments of HIV-1 DNA (50-150 bp) generated by random DNAse I cleavage. This peptide library, expressed in the yeast Saccharomyces cerevisiae, was screened with sera of HIV-1 infected individuals and human and murine anti-HIV-1 monoclonal antibodies. Plasmids from immunoreactive colonies were recovered and the sequences of the HIV-1 derived inserts were determined. By using human sera, we have detected classical HIV-1 epitopes and identified two novel major epitopes, which may be used to improve diagnostic tests, localized in the p24 core protein and in the endonuclease. In addition, four minor epitopes were also defined by screening the library with monoclonal antibodies: in the protease, in the p17 core protein, in gp120 and near the C-terminal of gp41. This method is general and can be used for any protein from which a cloned cDNA is available.
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PMID:A peptide library expressed in yeast reveals new major epitopes from human immunodeficiency virus type 1. 171 77

We evaluated the use of the INNO-LIA HIV-1/HIV-2 Ab test (LIA HIV; Innogenetics) for the confirmation of antibodies to human immunodeficiency virus type 1 (HIV-1) and type 2 (HIV-2). The test includes three recombinant HIV-1 proteins: p24 (gag), p17 (gag), and endonuclease (p31; pol), in combination with two synthetic peptides derived from the env gene of HIV-1 and one synthetic peptide selected from the env gene of HIV-2. Analysis of 450 sera from blood donors, 220 sera from patients with non-HIV pathology, and 28 Western blot (WB) p24-only reactive sera revealed no false-positive results, and the rate of indeterminate results was substantially lower than that with WB. Testing of 334 WB-confirmed HIV antibody-positive sera (309 HIV-1; 25 HIV-2) revealed no false-negative results. In two of seven seroconversion panels tested, LIA HIV detected the presence of HIV antibodies before WB did. In the other five panels, LIA HIV and WB confirmed the presence of HIV antibodies in the same sample. The LIA HIV assay therefore appears well suited for routine confirmation of the presence of HIV-1 and HIV-2 antibodies.
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PMID:Confirmation and differentiation of antibodies to human immunodeficiency virus 1 and 2 with a strip-based assay including recombinant antigens and synthetic peptides. 191 62

An ELISA procedure is described for the quantification of intrathecally synthesized immunoglobulin G antibodies to human immunodeficiency virus (HIV) antigens. Recombinant p17, p24, endonuclease (END), reverse transcriptase (RT), a peptide from the transmembrane region of gp41 (ENV80) and a fusion protein containing HIV-1 and HIV-2 epitopes were compared with a commercially available ELISA. Using a reference serum, antibodies in serum and cerebrospinal fluid (CSF) to all of the antigens could be measured quantitatively in a reliable and reproducible fashion. Despite the fact that the titer varied up to 10(5)-fold between CSF and serum, interassay variability ranged from 3.87% for p17 to 8.41% for RT and intra-assay variability varied from 3.9% +/- 1.2% for p17 to 14.3% +/- 3.9% for the commercial ELISA. Antibody specificity indices (ASI) obtained by relating CSF/serum titers with reference to the corresponding IgG concentrations can be used to detect intrathecal synthesis of virus specific antibodies.
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PMID:The use of recombinant antigens in ELISA procedures for the quantification of intrathecally produced HIV-1-specific antibodies. 199 6

Serum samples from 247 patients with positive HIV-1 IgG serology were investigated for specific IgM antibodies. We found that 109 also reacted positively with a least one antigen in an HIV-1 IgM Western Blot and only 31 in an HIV-1 IgM enzyme-linked immunosorbent assay (ELISA). It was shown that in some of the persons, specific IgM antibodies against the gp160/120, p66, p55, gp41, p24, and p17 antigens of the virus are synthesized at some time after infection. IgM antibodies to the endonuclease-related p31 antigen were observed in one serum only. IgM antibodies against the gp160/120, p66, gp41, and p17 antigens seemed to disappear early after infection. Those against the p55 and the p24 antigens were found in 62% and 75% of investigated cases, respectively. A direct correlation between the Western Blot patterns and the IgM ELISA results was not found.
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PMID:Detection of anti-HIV-1 immunoglobulin M antibodies in patients with serologically proved HIV-1 infection. 316 78

Serum samples from 27 patients infected with human T-cell lymphotropic virus type III (14 with acquired immune deficiency syndrome [AIDS] and 13 with AIDS-related complex) were examined for antibodies to viral proteins by the Western blot method and with four different commercial solid-phase enzyme-linked immunosorbent assays (ELISAs). Virus-specific bands on blots at molecular masses of 64, 55, 53, 41, 31, 24, and 17 kilodaltons were observed. Rank correlation matrices were calculated to relate the intensity of viral bands, stage of illness, and ELISA kit optical densities (ODs). Groups of bands tended to covary in intensity: p17, p24, and p55 (gag gene products); p53 and p64 (pol gene products); and p31 (pol/endonuclease gene product) and p41 (env gene product). Blots of sera from AIDS-related complex patients usually showed strong activity against all viral proteins, while those of sera from AIDS patients characteristically showed strong reactivity only at the pol/endonuclease and env bands. For one ELISA kit (Abbott Laboratories, North Chicago, Ill.), ODs correlated well with the env and pol band intensity scores, while ELISA ODs with other kits (from Litton Industries, Sunnyvale, Calif.; Electro-Nucleonics, Inc., Fairfield, N.J.; and E.I. du Pont de Nemours & Co., Inc., Wilmington, Del.) correlated closely with gag band intensity scores. We conclude that human T-cell lymphotropic virus type III Western blot patterns are determined by (i) viral protein processing pathways and (ii) the stage of illness of the patient and may reflect (iii) the ELISA method used for serum screening.
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PMID:Variations in Western blot banding patterns of human T-cell lymphotropic virus type III/lymphadenopathy-associated virus. 354 2

Two commercially available expression vectors were modified to generate plasmids pGEXcPk and pQ9cPk. Proteins expressed from pGEXcPk and pQ9cPk had a short oligopeptide tag termed Pk at their carboxy termini and either glutathione S-transferase (GST) or a small histidine (His) tag, respectively, at their N termini. GST fusion proteins can be purified on immobilized glutathione and proteins coupled to the His tag selectively bind to Ni(2+)-NTA columns. The Pk tag is recognized by monoclonal antibody (MAb) SV5-P-k, previously produced in our laboratory. Thus proteins expressed from the pGEXcPk and pQ9cPk vectors can be purified in a two-step procedure, first via the N-terminal tag and second via the C-terminal tag. The combination of two affinity purification steps significantly improves the antigen purity and selects for full-size proteins. Moreover, by using the MAbSV5-P-k in the second purification step, Pk-linked antigens can be assembled directly into solid matrix-antibody-antigen (SMAA) complexes for use as vaccines. The genes for nef, endonuclease, p15, p17, p27, protease, Rev, reverse transcriptase (rt), tat, vif, vpr, and vpx of simian immunodeficiency virus (SIV mac 251) were cloned and expressed as both GST-SIV-Pk and His-SIV-Pk proteins. Multivalent SMAA complexes were made that contained His-p17-Pk, His-p27-Pk, His-rt-Pk, His-vpx-Pk, and His-vpr-Pk. Following two immunizations of mice with this mixture, antibodies could be detected to all five SIV antigens. When compared to single-protein immunizations, the immunogenicity of some of the proteins in this cocktail was either enhanced or decreased. Mice were also immunized with His-p17-Pk or His-p17-Pk-antibody complexes in the presence or absence of alum. The antibody-antigen complexes induced two- to four-fold higher antibody levels than antigen alone but did not appear to be more immunogenic in inducing lymphoproliferative responses. Sera from SIV-infected macaques were tested for the presence of antibodies reacting with the recombinant proteins by Western blot analysis. Antibodies to endonuclease, p15, p17, p27, rt, and vif were readily detected, antibodies against protease and vpx were present at much lower levels, but no antibodies were detected to nef, rev, tat, or vpr. Thus, we have developed a comprehensive range of reagents (available on request) that can be used to examine immune responses to SIV in both mice and monkeys.
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PMID:Expression and purification of nonglycosylated SIV proteins, and their use in induction and detection of SIV-specific immune responses. 807 30