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Mótyán JA, Kassay N, Matúz K, Tőzsér J. Different Mutation Tolerance of Lentiviral (HIV-1) and Deltaretroviral (BLV and HTLV) Protease Precursors. Viruses 2022; 14:v14091888. [PMID: 36146695 PMCID: PMC9505669 DOI: 10.3390/v14091888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 08/17/2022] [Accepted: 08/24/2022] [Indexed: 11/16/2022] Open
Abstract
The bovine leukemia virus (BLV) and the human T-lymphothropic viruses (HTLVs) are members of the deltaretrovirus genus of Retroviridae family. An essential event of the retroviral life cycle is the processing of the polyproteins by the viral protease (PR); consequently, these enzymes became important therapeutic targets of the anti-retroviral drugs. As compared to human immunodeficiency viruses (HIVs), the deltaretroviruses have a different replication strategy, as they replicate predominantly in the DNA form, by forcing the infected cell to divide, unlike HIV-1, which replicates mainly by producing a vast number of progeny virions and by reinfection. Due to bypassing the error-prone reverse transcription step of replication, the PRs of deltaretroviruses did not undergo such extensive evolution as HIV PRs and remained more highly conserved. In this work, we studied the abilities of wild-type and modified BLV, HTLV (type 1, 2 and 3), and HIV-1 PRs (fused to an N-terminal MBP tag) for self-processing. We designed a cleavage site mutant MBP-fused BLV PR precursor as well, this recombinant enzyme was unable for self-proteolysis, the MBP fusion tag decreased its catalytic efficiency but showed an unusually low Ki for the IB-268 protease inhibitor. Our results show that the HTLV and BLV deltaretrovirus PRs exhibit lower mutation tolerance as compared to HIV-1 PR, and are less likely to retain their activity upon point mutations at various positions, indicating a higher flexibility of HIV-1 PR in tolerating mutations under selective pressure.
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Affiliation(s)
- János András Mótyán
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary
- Correspondence: (J.A.M.); (J.T.); Tel.: +36-52-512-900 (J.A.M. & J.T.)
| | - Norbert Kassay
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary
- Doctoral School of Molecular Cell and Immune Biology, University of Debrecen, 4032 Debrecen, Hungary
| | - Krisztina Matúz
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary
| | - József Tőzsér
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary
- Correspondence: (J.A.M.); (J.T.); Tel.: +36-52-512-900 (J.A.M. & J.T.)
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Fló M, Carrión F, Olivero-Deibe N, Bianchi S, Portela M, Rammauro F, Alvarez B, Pritsch O. Kinetics of Bovine leukemia virus aspartic protease reveals its dimerization and conformational change. PLoS One 2022; 17:e0271671. [PMID: 35867649 PMCID: PMC9307154 DOI: 10.1371/journal.pone.0271671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2022] [Accepted: 07/05/2022] [Indexed: 11/28/2022] Open
Abstract
The retropepsin (PR) of the Bovine leukemia virus (BLV) plays, as in other retroviruses, a crucial role in the transition from the non-infective viral particle to the infective virion by processing the polyprotein Gag. PR is expressed as an immature precursor associated with Gag, after an occasional −1 ribosomal frameshifting event. Self-hydrolysis of PR at specific N- and C-terminal sites releases the monomer that dimerizes giving rise to the active protease. We designed a strategy to express BLV PR in E. coli as a fusion protein with maltose binding protein, with a six-histidine tag at its N-terminal end, and bearing a tobacco etch virus protease hydrolysis site. This allowed us to obtain soluble and mature recombinant PR in relatively good yields, with exactly the same amino acid composition as the native protein. As PR presents relative promiscuity for the hydrolysis sites we designed four fluorogenic peptide substrates based on Förster resonance energy transfer (FRET) in order to characterize the activity of the recombinant enzyme. These substrates opened the way to perform kinetic studies, allowing us to characterize the dimer-monomer equilibrium. Furthermore, we obtained kinetic evidence for the existence of a conformational change that enables the interaction with the substrate. These results constitute a starting point for the elucidation of the kinetic properties of BLV-PR, and may be relevant not only to improve the chemical warfare against this virus but also to better understand other viral PRs.
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Affiliation(s)
- Martín Fló
- Laboratorio de Inmunovirología, Institut Pasteur de Montevideo, Montevideo, Uruguay
- Departamento de Inmunobiología, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
- * E-mail: (OP); (MF)
| | - Federico Carrión
- Laboratorio de Inmunovirología, Institut Pasteur de Montevideo, Montevideo, Uruguay
| | | | - Sergio Bianchi
- Laboratorio de Inmunovirología, Institut Pasteur de Montevideo, Montevideo, Uruguay
- Laboratorio de Biomarcadores Moleculares, Departamento de Fisiopatología, Hospital de Clínicas, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
| | - Madelón Portela
- Unidad de Bioquímica y Proteómica Analíticas, Institut Pasteur de Montevideo, Facultad de Ciencias, Montevideo, Uruguay
| | - Florencia Rammauro
- Laboratorio de Inmunovirología, Institut Pasteur de Montevideo, Montevideo, Uruguay
- Departamento de Inmunobiología, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
| | - Beatriz Alvarez
- Laboratorio de Enzimología, Instituto de Química Biológica, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Otto Pritsch
- Laboratorio de Inmunovirología, Institut Pasteur de Montevideo, Montevideo, Uruguay
- Departamento de Inmunobiología, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
- * E-mail: (OP); (MF)
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Pourrezaei S, Shadabi S, Gheidishahran M, Rahimiforoushani A, Akhbari M, Tavakoli M, Safavi M, Madihi M, Norouzi M. Molecular epidemiology and phylogenetic analysis of human T-lymphotropic virus type 1 in the tax gene and it association with adult t-cell leukemia/lymphoma disorders. IRANIAN JOURNAL OF MICROBIOLOGY 2021; 13:509-517. [PMID: 34557280 PMCID: PMC8421578 DOI: 10.18502/ijm.v13i4.6976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Background and Objectives: Human T-lymphotropic virus type-1 (HTLV-1) belongs to retrovirus family that causes the neurological disorder HTLV-1 adult T-cell leukemia/lymphoma (ATLL). Since 1980, seven subtypes of the virus have been recognized. HTLV-1 is prevalent and endemic in some regions, such as Africa, Japan, South America and Iran as the endemic regions of the HTLV-1 in the Middle East. To study HTLV-1 subtypes and routes of virus spread in Iran, phylogenetic and phylodynamic analyses were performed and for as much as no previous phylogenetic studies were conducted in Tehran, we do this survey. To this purpose, the Tax region of HTLV-1 was used. Materials and Methods: In this study 100 samples were collected from blood donors in Tehran. All samples were screened for anti-HTLV-I antibodies by ELISA. Then, genomic DNA was extracted from all positive samples (10 people), and for confirmation of infection, ordinary PCR was performed for both the HBZ and LTR regions. Moreover, the Tax region was amplified and purified PCR products were sequenced and analyzed, and finally, a phylogenetic tree was constructed using Mega X software. Results: Phylogenetic analysis confirmed that isolates from Iran, Japan, Brazil, and Africa are located within the extensive “transcontinental” subgroup A clade of HTLV-1 Cosmopolitan subtype a. The Japanese sequences are the closest to the Iranian sequences and have the most genetic similarity with them. Conclusion: Through phylogenetic and phylodynamic analyses HTLV-1 strain in Tehran were characterized in Iran. The appearance of HTLV-1 in Iran was probably happened by the ancient Silk Road which linked China to Antioch.
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Affiliation(s)
- Samira Pourrezaei
- Department of Virology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Shahrzad Shadabi
- Department of Virology, School of Medical Sciences, Kerman University of Medical Sciences, Kerman, Iran
| | - Maryam Gheidishahran
- Department of Medical Hematology and Blood Transfusion, School of Allied Medical Science, Iran University of Medical Sciences, Tehran, Iran
| | - Abbas Rahimiforoushani
- Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Masoume Akhbari
- Department of Molecular Medicine, School of Medical Science, Karaj University of Medical Sciences, Karaj, Iran
| | - Mahnaz Tavakoli
- Department of Medical Microbiology, School of Medical Science, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mahshid Safavi
- Department of Medical Microbiology, School of Medical Science, Karaj University of Medical Sciences, Iran
| | - Mobina Madihi
- Department of Virology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Mehdi Norouzi
- Department of Virology, School of Public Health and Institute of Health Research, Tehran University of Medical Sciences, Tehran, Iran.,Research Center for Clinical Virology, Tehran University of Medical Sciences, Tehran, Iran
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Kassay N, Mótyán JA, Matúz K, Golda M, Tőzsér J. Biochemical Characterization, Specificity and Inhibition Studies of HTLV-1, HTLV-2, and HTLV-3 Proteases. Life (Basel) 2021; 11:life11020127. [PMID: 33562087 PMCID: PMC7915765 DOI: 10.3390/life11020127] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 02/02/2021] [Accepted: 02/03/2021] [Indexed: 01/03/2023] Open
Abstract
The human T-lymphotropic viruses (HTLVs) are causative agents of severe diseases including adult T-cell leukemia. Similar to human immunodeficiency viruses (HIVs), the viral protease (PR) plays a crucial role in the viral life-cycle via the processing of the viral polyproteins. Thus, it is a potential target of anti-retroviral therapies. In this study, we performed in vitro comparative analysis of human T-cell leukemia virus type 1, 2, and 3 (HTLV-1, -2, and -3) proteases. Amino acid preferences of S4 to S1′ subsites were studied by using a series of synthetic oligopeptide substrates representing the natural and modified cleavage site sequences of the proteases. Biochemical characteristics of the different PRs were also determined, including catalytic efficiencies and dependence of activity on pH, temperature, and ionic strength. We investigated the effects of different HIV-1 PR inhibitors (atazanavir, darunavir, DMP-323, indinavir, ritonavir, and saquinavir) on enzyme activities, and inhibitory potentials of IB-268 and IB-269 inhibitors that were previously designed against HTLV-1 PR. Comparative biochemical analysis of HTLV-1, -2, and -3 PRs may help understand the characteristic similarities and differences between these enzymes in order to estimate the potential of the appearance of drug-resistance against specific HTLV-1 PR inhibitors.
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Affiliation(s)
- Norbert Kassay
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (N.K.); (K.M.); (M.G.)
- Doctoral School of Molecular Cell and Immune Biology, University of Debrecen, 4032 Debrecen, Hungary
| | - János András Mótyán
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (N.K.); (K.M.); (M.G.)
- Correspondence: (J.A.M.); (J.T.); Tel.: +36-52-512-900 (J.A.M. & J.T.)
| | - Krisztina Matúz
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (N.K.); (K.M.); (M.G.)
| | - Mária Golda
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (N.K.); (K.M.); (M.G.)
- Doctoral School of Molecular Cell and Immune Biology, University of Debrecen, 4032 Debrecen, Hungary
| | - József Tőzsér
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (N.K.); (K.M.); (M.G.)
- Correspondence: (J.A.M.); (J.T.); Tel.: +36-52-512-900 (J.A.M. & J.T.)
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Dimer Interface Organization is a Main Determinant of Intermonomeric Interactions and Correlates with Evolutionary Relationships of Retroviral and Retroviral-Like Ddi1 and Ddi2 Proteases. Int J Mol Sci 2020; 21:ijms21041352. [PMID: 32079302 PMCID: PMC7072860 DOI: 10.3390/ijms21041352] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 02/11/2020] [Accepted: 02/14/2020] [Indexed: 02/07/2023] Open
Abstract
The life cycles of retroviruses rely on the limited proteolysis catalyzed by the viral protease. Numerous eukaryotic organisms also express endogenously such proteases, which originate from retrotransposons or retroviruses, including DNA damage-inducible 1 and 2 (Ddi1 and Ddi2, respectively) proteins. In this study, we performed a comparative analysis based on the structural data currently available in Protein Data Bank (PDB) and Structural summaries of PDB entries (PDBsum) databases, with a special emphasis on the regions involved in dimerization of retroviral and retroviral-like Ddi proteases. In addition to Ddi1 and Ddi2, at least one member of all seven genera of the Retroviridae family was included in this comparison. We found that the studied retroviral and non-viral proteases show differences in the mode of dimerization and density of intermonomeric contacts, and distribution of the structural characteristics is in agreement with their evolutionary relationships. Multiple sequence and structure alignments revealed that the interactions between the subunits depend mainly on the overall organization of the dimer interface. We think that better understanding of the general and specific features of proteases may support the characterization of retroviral-like proteases.
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Lyngdoh D, Shukla H, Sonkar A, Anupam R, Tripathi T. Portrait of the Intrinsically Disordered Side of the HTLV-1 Proteome. ACS OMEGA 2019; 4:10003-10018. [PMID: 31460093 PMCID: PMC6648719 DOI: 10.1021/acsomega.9b01017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 05/28/2019] [Indexed: 05/07/2023]
Abstract
Intrinsically disordered proteins (IDPs) lack an ordered 3D structure. These proteins contain one or more intrinsically disordered protein regions (IDPRs). IDPRs interact promiscuously with other proteins, which leads to their structural transition from a disordered to an ordered state. Such interaction-prone regions of IDPs are known as molecular recognition features. Recent studies suggest that IDPs provide structural plasticity and functional diversity to viral proteins that are involved in rapid replication and immune evasion within the host cells. In the present study, we evaluated the prevalence of IDPs and IDPRs in human T lymphotropic virus type 1 (HTLV-1) proteome. We also investigated the presence of MoRF regions in the structural and nonstructural proteins of HTLV-1. We found abundant IDPRs in HTLV-1 bZIP factor, p30, Rex, and structural nucleocapsid p15 proteins, which are involved in diverse functions such as virus proliferation, mRNA export, and genomic RNA binding. Our study analyzed the HTLV-1 proteome with the perspective of intrinsic disorder identification. We propose that the intrinsic disorder analysis of HTLV-1 proteins may form the basis for the development of protein disorder-based drugs.
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Affiliation(s)
- Denzelle
L. Lyngdoh
- Molecular
and Structural Biophysics Laboratory, Department of Biochemistry, North-Eastern Hill University, Shillong 793022, India
| | - Harish Shukla
- Molecular
and Structural Biophysics Laboratory, Department of Biochemistry, North-Eastern Hill University, Shillong 793022, India
| | - Amit Sonkar
- Molecular
and Structural Biophysics Laboratory, Department of Biochemistry, North-Eastern Hill University, Shillong 793022, India
| | - Rajaneesh Anupam
- Department
of Biotechnology, Dr. Harisingh Gour Central
University, Sagar 470003, India
| | - Timir Tripathi
- Molecular
and Structural Biophysics Laboratory, Department of Biochemistry, North-Eastern Hill University, Shillong 793022, India
- E-mail: , . Phone: +91-364-2722141. Fax: +91-364-2550108
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Selvaraj C, Omer A, Singh P, Singh SK. Molecular insights of protein contour recognition with ligand pharmacophoric sites through combinatorial library design and MD simulation in validating HTLV-1 PR inhibitors. MOLECULAR BIOSYSTEMS 2014; 11:178-89. [PMID: 25335799 DOI: 10.1039/c4mb00486h] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Retroviruses HIV-1 and HTLV-1 are chiefly considered to be the most dangerous pathogens in Homo sapiens. These two viruses have structurally unique protease (PR) enzymes, which are having common function of its replication mechanism. Though HIV PR drugs failed to inhibit HTLV-1 infections, they emphatically emphasise the need for designing new lead compounds against HTLV-1 PR. Therefore, we tried to understand the binding level interactions through the charge environment present in both ligand and protein active sites. The domino effect illustrates that libraries of purvalanol-A are attuned to fill allosteric binding site of HTLV-1 PR through molecular recognition and shows proper binding of ligand pharmacophoric features in receptor contours. Our screening evaluates seven compounds from purvalanol-A libraries, and these compounds' pharmacophore searches for an appropriate place in the binding site and it places well according to respective receptor contour surfaces. Thus our result provides a platform for the progress of more effective compounds, which are better in free energy calculation, molecular docking, ADME and molecular dynamics studies. Finally, this research provided novel chemical scaffolds for HTLV-1 drug discovery.
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Affiliation(s)
- Chandrabose Selvaraj
- Computer Aided Drug Design and Molecular Modeling Lab, Department of Bioinformatics, Science Block, Alagappa University, Karaikudi-630004, Tamilnadu, India.
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Matúz K, Mótyán J, Li M, Wlodawer A, Tőzsér J. Inhibition of XMRV and HIV-1 proteases by pepstatin A and acetyl-pepstatin. FEBS J 2012; 279:3276-86. [PMID: 22804908 PMCID: PMC6290463 DOI: 10.1111/j.1742-4658.2012.08714.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The kinetic properties of two classical inhibitors of aspartic proteases (PRs), pepstatin A and acetyl-pepstatin, were compared in their interactions with HIV-1 and xenotropic murine leukemia virus related virus (XMRV) PRs. Both compounds are substantially weaker inhibitors of XMRV PR than of HIV-1 PR. Previous kinetic and structural studies characterized HIV-1 PR-acetyl-pepstatin and XMRV PR-pepstatin A complexes and suggested dramatically different binding modes. Interaction energies were calculated for the possible binding modes and suggested a strong preference for the one-inhibitor binding mode for HIV-1 PR-acetyl-pepstatin and the two-inhibitor binding mode for XMRV PR-pepstatin A interactions. Comparison of the molecular models suggested that in the case of XMRV PR the relatively unfavorable interactions at S3' and the favorable interactions at S4 and S4' sites with the statine residues may shift the ground state binding towards the two-inhibitor binding mode, whereas the single molecule ground state binding of statines to the HIV-1 PR appear to be more favorable. The preferred single molecular binding to HIV-1 PR allows the formation of the transition state complex, represented by substantially better binding constants. Intriguingly, the crystal structure of the complex of acetyl-pepstatin with XMRV PR has shown a mixed type of binding: the unusual binding mode of two molecules of the inhibitor to the enzyme, in a mode very similar to the previously determined complex with pepstatin A, together with the classical binding mode found for HIV-1 PR. The structure is thus in good agreement with the very similar interaction energies calculated for the two types of binding.
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Affiliation(s)
- Krisztina Matúz
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - János Mótyán
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Mi Li
- Protein Structure Section, Macromolecular Crystallography Laboratory, National Cancer Institute - Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
- Basic Research Program, SAIC-Frederick, Frederick, MD 21702, USA
| | - Alexander Wlodawer
- Protein Structure Section, Macromolecular Crystallography Laboratory, National Cancer Institute - Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
| | - József Tőzsér
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
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Prediction and identification of sequences coding for orphan enzymes using genomic and metagenomic neighbours. Mol Syst Biol 2012; 8:581. [PMID: 22569339 PMCID: PMC3377989 DOI: 10.1038/msb.2012.13] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Accepted: 03/24/2012] [Indexed: 11/09/2022] Open
Abstract
Many characterized metabolic enzymes currently lack associated gene and protein sequences. Here, pathway and genomic neighbour data are used to assign genes to these ‘orphan enzymes,' and the predictions are validated with experimental assays and genome-scale metabolic modelling. ![]()
A computational method is developed for assigning candidate sequences to orphan enzymes. The method uses metabolic pathway, genomic neighbourhood, genomic co-occurrence, and protein domain information to predict genes that are likely to perform a particular enzymatic function. Benchmarking of the scoring scheme based on the 4 features above revealed that some combinations of parameters yielded greater than 70% accuracy, and that high-confidence predictions could be generated for 131 orphan enzymes. Enzyme assay experiments confirmed the predicted enzymatic activity for two of the high-confidence candidate sequences. Predicted functions can improve the annotation of genomic and metagenomic data, and can reveal putative genes for enzymes with potential biotechnological applications. Incorporating the predicted enzymatic reactions into genome-scale metabolic models changed the flux connectivity and improved their ability to correctly predict gene essentiality, supporting the biological relevance of these predictions.
Despite the current wealth of sequencing data, one-third of all biochemically characterized metabolic enzymes lack a corresponding gene or protein sequence, and as such can be considered orphan enzymes. They represent a major gap between our molecular and biochemical knowledge, and consequently are not amenable to modern systemic analyses. As 555 of these orphan enzymes have metabolic pathway neighbours, we developed a global framework that utilizes the pathway and (meta)genomic neighbour information to assign candidate sequences to orphan enzymes. For 131 orphan enzymes (37% of those for which (meta)genomic neighbours are available), we associate sequences to them using scoring parameters with an estimated accuracy of 70%, implying functional annotation of 16 345 gene sequences in numerous (meta)genomes. As a case in point, two of these candidate sequences were experimentally validated to encode the predicted activity. In addition, we augmented the currently available genome-scale metabolic models with these new sequence–function associations and were able to expand the models by on average 8%, with a considerable change in the flux connectivity patterns and improved essentiality prediction.
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Demir A, Oguariri RM, Magis A, Ostrov DA, Imamichi T, Dunn BM. Kinetic characterization of newly discovered inhibitors of various constructs of human T-cell leukemia virus-1 (HTLV-1) protease and their effect on HTLV-1-infected cells. Antivir Ther 2012; 17:883-92. [PMID: 22436331 DOI: 10.3851/imp2090] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/08/2011] [Indexed: 10/28/2022]
Abstract
BACKGROUND Human T-cell leukemia virus-1 (HTLV-1) was the first identified human retrovirus and was shown to be associated with diseases such as adult T-cell leukemia lymphoma and tropical spastic paraparesis/HTLV-1 associated myelopathy. Retroviral proteases (PRs) are essential for viral replication by processing viral Gag and Gag-(Pro)-Pol polyproteins during maturation. Full-length HTLV-1 PR is 125 residues long; whether the C-terminal region is required for catalytic activity is still controversial. In this study, we characterized the effect of C-terminal amino acids of HTLV-1 PR for PR activity and examined the binding of compounds identified by in silico screening. One compound showed inhibition against the virus in infected cells. METHODS Truncated (116-, 121- and 122-residue) forms of HTLV-1 PR were prepared and proteins from expression of the genes were purified. In silico screening was performed by docking small molecules into the active site of HTLV-1 PR. The kinetic constants k(cat), K(m), k(cat)/K(m) and inhibition constants K(i) for inhibitors identified by the computational screening were determined. Western blot and ELISA analyses were used to determine the effect of the most potent PR inhibitors on HTLV-1 protein processing in infected cells. RESULTS The constructs showed similar catalytic efficiency constants (k(cat)/K(m)); thus HTLV-1 PR C-terminal amino acids are not essential for full activity. Computational screening revealed new PR inhibitors and some were shown to be inhibitory in enzyme assays. In HTLV-1-infected cells, one of the small molecules inhibited HTLV-1 gag cleavage and decreased the amount of HTLV-1 p19 produced in the cells. CONCLUSIONS We have identified an HTLV-1 PR inhibitor that is biologically functional. Inhibitor screening will continue to develop possible drugs for therapy of HTLV-1 infection.
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Affiliation(s)
- Ahu Demir
- University of Florida College of Medicine Biochemistry and Molecular Biology, Gainesville, FL, USA
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Kumada HO, Nguyen JT, Kakizawa T, Hidaka K, Kimura T, Hayashi Y, Kiso Y. Development of [Ile40]HTLV-I protease inhibition assay using novel fluorogenic and chromogenic substrate. J Pept Sci 2011; 17:569-75. [DOI: 10.1002/psc.1375] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2011] [Revised: 03/09/2011] [Accepted: 03/11/2011] [Indexed: 11/07/2022]
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12
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Li C, Li X, Lu W. Total chemical synthesis of human T-cell leukemia virus type 1 protease via native chemical ligation. Biopolymers 2010; 94:487-94. [PMID: 20593478 DOI: 10.1002/bip.21375] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Human T-cell leukemia virus 1 (HTLV-1) protease, a member of the aspartic acid protease family, plays critical roles in the pathogenesis of the virus and is an attractive viral target for therapeutic intervention. HTLV-1 protease consists of 125 amino acid residues and functions as a homodimer stabilized in part by a four-stranded beta-sheet comprising the N- and C-termini. Compared with many other viral proteases such as HIV-1 protease, HTLV-1 protease is elongated by an extra 10 amino acid residue "tail" at the C-terminus. The structural and functional role of the extra C-terminal residues in the catalysis of HTLV-1 protease has been a subject of debate for years. Using the native chemical ligation technique pioneered by Kent and coworkers, we chemically synthesized a full-length HTLV protease and a C-terminally truncated form encompassing residues 1-116. Enzyme kinetic analysis using three different peptide substrates indicated that truncation of the C-terminal tail lowered the turnover number of the viral enzyme by a factor of 2 and its catalytic efficiency by roughly 10-fold. Our findings differ from the two extreme views that the C-terminal tail of HTLV-1 protease is either fully dispensable or totally required for enzyme dimerization and/or catalysis.
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Affiliation(s)
- Changqing Li
- Institute of Human Virology, University of Maryland School of Medicine, 725 West Lombard Street, Baltimore, MD 21201, USA
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