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@#To discuss the conformational change and the recognition mechanism of hydroxy isoindol ketone derivatives with HIV-1 integrase, fifty-eight hydroxy isoindol ketone derivatives were docked to the integrase using AutoDock program. Molecular dynamics simulation with 16 ns was carried out for the two complex modes, respectively, in which the corresponding small molecules exhibited strong inhibition ability. Main force acting on the association of small molecules with integrase was explored based on the docking complex model. After analyzing the hydrogen-bond and conformational changes, it was found that the hydrogen-bond between N155 and D64 was the key factor maintaining the DDE motif stability. Furthermore, the hydrophobic interactions between the loop region where Y143 located and the hydroxy isoindol ketone derivatives were found to play an important role for their recognition.
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Objective To construct recombinant eukaryotic expression vector for EGFP fused HIV-1 integrase expression. Methods Wild type of HIV-1 integrase gene was cloned into eukaryotic expression vector-pcDNA6/V5-HisA. After restricted enzyme mapping, PCR confirmation and sequence confirmation, the recombinant plasmid was transfected into HeLa cells with Lipofectamine2000. After 24 hours, the expression of integrase was examined by immunofluorescence with confocal fluorescent microscopy. The cells were fixed with 4%paraformaledhyde. The cell nuclei were stained with Propidium Iodide (PI). Then the expression was imaged and analyzed with Confocal Microscopy. Results The integrase expressed significantly in HeLa cells in 24 hours after transfection. Integrase was expressed and localized into nuclei mainly. After fixed with 4% paraformaldehyde, the cell nuclei were stained with PI. When nuclei were showed in red in normal cells, the nuclei with integrase over expression turned yellow or orange. Conclusion The construction of eukaryotic expression vector of integrase was successful. Integrase was expressed and localized into nuclei mainly after transfection in HeLa cells.
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The drug resistant mutations in human immunodefieiency virus type 1 (HIV-1) are a major impediment to successful highly active antiretrovirai therapy (HAART) and new drug design. In order to understand the drug resistance mechanism of HIV-1 integrase (IN) mutually existed for multiple drug-resistant strains to the most potent IN inhibitors diketo acids (DKAs), three S-1360-resistant HIV-1 strains were selected and molecular docking and molecular dynamics (MD) simulations were performed to obtain the inhibitor binding modes. Based on the binding modes, compelling differences between the wild-type and the 3 mutants for IN have been observed. The results showed that: 1) In the mutants, the inhibitor is close to the funetional loop 3 region but far away from the DNA binding site. Different binding sites lead to the decrease in susceptibility to S-1360 in mutants compared to the wild-type IN. 2) The fluctuations in the region of residues 138～166 are important to the biological function of IN. 2 hydrogen-bonds between S-1360 with residues N155 and K159 restrict the flexibility of the region. Drug resistant mutations result in a lack of the interaction, consequently, the less susceptible to S-1360. 3) In the 3 mutant IN complexes, the benzyl ring of S-1360 is far from the viral DNA binding site, thus, S-1360 can not prevent the end of the viral DNA from exposure to human DNA. 4) After T66I mutation, the long side chain of I occupied the active pocket in the 3 mutants, consequently, the inhibitor could not move into the same binding site or have the same orientation. All the above contribute to drug resistance. These results will be useful for the rational inhibitor modify and design.
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Aim: To develop a practical synthetic route of raltegravir, a drug for HIV treatment. Methods: Raltegravir was synthesized through an eight-step process including aminonitrile formation, protection with benzyloxy-carbonyl group, conversion of the nitrile to the amidoxime, cyclization to form hydroxypyrimidinone, N-methyla-tion, amidation with microwave-assistance, deprotection, amidation with acyl chloride. Results: The overall yield of the eight-step synthesis is about 12. 0% and the structure of the target compound was confirmed by ~1H NMR, ~(13)C NMR, LR-MS and HR-MS. Conclusion: The reported synthetic process of raltegravir highlights the advantages in terms of readily available starting materials, convenient operation and low cost.
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The pol gene of HIV-1 encodes mainly three enzymes: reverse transcriptase (RT), protease (PR) and integrase (IN). Currently, FDA approved drugs targeting RT and PR are available and administered in various combinations, while no anti-IN drug was approved. HIV-1 integrase is an essential enzyme for the viral replication and an interesting target for the design of new pharmaceuticals for multi-drug therapy of AIDS. The 288 amino acids of IN (32kDa) recognizes specific sequences in the long terminal repeats (LTRs) of the retroviral DNA. The IN protein catalyzes the 3′-processing step and the 5′-strand transfer step reaction in vivo, which was called integration and this reaction could be analysed by ELISA Assay in vitro. It has been reported that F185K and C280S mutations of HIV-1 integrase would improve the enzyme solubility, and the catalytical activity of the enzyme was the same as that of the wild-type enzyme in vitro. In order to build the platform of screening inhibitor against integrase of HIV-1 virus, the IN enzyme was expressed and the function of integrase protein was assayed. The cDNA of clade B HIV-1 genome was used as a template, overlapped PCR was used to construct site mutagenesis of F185K/C280S and NdeI/Xho I restriction sites were brought in. The PCR product was cloned into the prokaryotic vector pET-28a(+) to form a recombined plasmid, transferred into the host cell E.coli(BL21 DE3). The recombined clones were identified by PCR and Nde I/Xho I digestion .The positive plasmid was sequenced, and the successfully recombined plasmid in the host cell was induced by IPTG. The expressed IN protein was puriied sy the Co+ affinity chromatography column and SDS-PAGE was used to analyze the molecular weight and specificity. In addition, ELISA assay was used to analyze the function of the recombined IN protein. The recombinant protein was soluble, and expressed highly and stably in E.coli. The molecular weight of the expression product was identical to the expectation. The IN protein was proved to be functional in 3′ processing and 5′strand transfer by ELISA. It will be helpful to build the platform of screening inhibitors against HIV-1 integrase.
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Integration is a critical step in the retroviral life cycle.HIV-1 integrase is involved in the integration of HIV DNA into host chromosomal DNA and appears to have no functionally equivalent in human cells.It has become an attractive and rational target for selective anti-AIDS therapy.A random linear heptapeptides phage display library was panned on the recombinant HIV-1 integrase protein.After five rounds of panning,13 positive phage clones were selected and sequenced.Two consensus peptides(TPSHSSR and HPERATL) were chemically synthesized.The non-radioactive ELISA-based HIV-1 integrase assay showed that the synthetic peptides TPSHSSR and HPERATL were able to inhibit the 3'cleavage or strand transfer activity of HIV-1 integrase to some extent(IC50=(54.56?5.18) ?mol/L,IC50=(28.29?1.32) ?mol/L,respectively) .These heptapeptides could be used for developing new anti-HIV drug candidates,as well as for structural studies of the three-dimensional structure of the entire integrase molecule.