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Zhang L, Kiruba GSM, Lee JK. Gas-Phase Studies of Hypoxanthine-Guanine-(Xanthine) Phosphoribosyltransferase (HG(X)PRT) Substrates. J Org Chem 2023. [PMID: 37220241 DOI: 10.1021/acs.joc.3c00115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The gas-phase acidity and proton affinity of nucleobases that are substrates for the enzyme Plasmodium falciparum hypoxanthine-guanine-(xanthine) phosphoribosyltransferase (Pf HG(X)PRT) have been examined using both computational and experimental methods. These thermochemical values have not heretofore been measured and provide experimental data to benchmark the theoretical results. Pf HG(X)PRT is a target of interest in the development of antimalarials. We use our gas-phase results to lend insight into the Pf HG(X)PRT mechanism, and also propose kinetic isotope studies that could potentially differentiate between possible mechanisms.
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Affiliation(s)
- Lanxin Zhang
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, New Brunswick, New Jersey 08901, United States
| | - G S M Kiruba
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, New Brunswick, New Jersey 08901, United States
| | - Jeehiun K Lee
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, New Brunswick, New Jersey 08901, United States
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2
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Hosoya T, Uchida S, Shibata S, Tomioka NH, Hosoyamada M. Perfecting a high hypoxanthine phosphoribosyltransferase activity-uricase KO mice to test the effects of purine- and non-purine-type xanthine dehydrogenase (XDH) inhibitors. Br J Pharmacol 2020; 177:2274-2285. [PMID: 31971609 PMCID: PMC7174878 DOI: 10.1111/bph.14978] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 10/25/2019] [Accepted: 12/12/2019] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND AND PURPOSE Purine metabolism in mice and human differ in terms of uricase (Uox) activity as well as hypoxanthine phosphoribosyltransferase (HPRT) activity. The aim of this study was the establishment of high HPRT activity-Uox knockout (KO) mice as a novel hyperuricaemic model. Then to investigate the effects of purine-type xanthine dehydrogenase (XDH) inhibitor, allopurinol, and non-purine-type XDH inhibitor, topiroxostat, on purine metabolism. EXPERIMENTAL APPROACH A novel hyperuricaemic mouse model was established by mating B6-ChrXCMSM mice with uricase KO mice. The pharmacological effects of allopurinol and topiroxostat were explored by evaluating urate, hypoxanthine, xanthine and creatinine in the plasma and urine of these model mice. Furthermore, we analysed the effect of both drugs on erythrocyte hypoxanthine phosphoribosyltransferase activity. KEY RESULTS Plasma urate level and urinary urate/creatinine ratio significantly decreased after administration of allopurinol 30 mg·kg-1 or topiroxostat 1 mg·kg-1 for 7 days. The urate-lowering effect was equivalent for allopurinol and topiroxostat. However, the urinary hypoxanthine/creatinine ratio and xanthine/creatinine ratio after treatment with topiroxostat were significantly lower than for allopurinol. In addition, the urinary oxypurine/creatinine ratio was significantly lowered after treatment with topiroxostat, but allopurinol elicited no such effect. Furthermore, allopurinol inhibited mouse erythrocyte hypoxanthine phosphoribosyltransferase, while topiroxostat did not. CONCLUSIONS AND IMPLICATIONS High hypoxanthine phosphoribosyltransferase activity- uricase KO mice were established as a novel hyperuricaemic animal model. In addition, topiroxostat, a non-purine-type xanthine dehydrogenase inhibitor, elicited a potent plasma urate-lowering effect. However, unlike allopurinol, topiroxostat did not perturb the salvage pathway, resulting in lowered total oxypurine excretion.
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Affiliation(s)
- Takuji Hosoya
- Department of Human Physiology & Pathology, Faculty of Pharma‐ScienceTeikyo UniversityTokyoJapan
- Biological Research Department, Medical R&D DivisionFuji Yakuhin Co., Ltd.SaitamaJapan
| | - Shunya Uchida
- Division of Nephrology, Department of Internal MedicineTeikyo University School of MedicineTokyoJapan
| | - Shigeru Shibata
- Division of Nephrology, Department of Internal MedicineTeikyo University School of MedicineTokyoJapan
| | - Naoko H. Tomioka
- Department of Human Physiology & Pathology, Faculty of Pharma‐ScienceTeikyo UniversityTokyoJapan
| | - Makoto Hosoyamada
- Department of Human Physiology & Pathology, Faculty of Pharma‐ScienceTeikyo UniversityTokyoJapan
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Jayanth N, Ogirala N, Yadav A, Puranik M. Structural basis for substrate discrimination by E. colirepair enzyme, AlkB. RSC Adv 2018; 8:1281-1291. [PMID: 35540905 PMCID: PMC9076979 DOI: 10.1039/c7ra11333a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2017] [Accepted: 11/14/2017] [Indexed: 11/21/2022] Open
Abstract
Positive charge on methylated nucleotides is a prime criterion for substrate recognition byE. coliAlkB.
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Affiliation(s)
- Namrata Jayanth
- National Centre for Biological Sciences
- Tata Institute of Fundamental Research
- GKVK Campus
- Bangalore 560065
- India
| | - Nirmala Ogirala
- National Centre for Biological Sciences
- Tata Institute of Fundamental Research
- GKVK Campus
- Bangalore 560065
- India
| | - Anil Yadav
- Indian Institute of Science Education and Research (IISER)
- Pune
- India
| | - Mrinalini Puranik
- National Centre for Biological Sciences
- Tata Institute of Fundamental Research
- GKVK Campus
- Bangalore 560065
- India
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Jayanth N, Puranik M. Mechanism of Discrimination of 8-Oxoguanosine versus Guanosine by Escherichia coli Fpg. J Phys Chem B 2017; 121:5679-5687. [DOI: 10.1021/acs.jpcb.7b00205] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Namrata Jayanth
- National Centre for Biological
Sciences, TIFR, GKVK Campus, Bellary Road, Bangalore 560065, India
| | - Mrinalini Puranik
- National Centre for Biological
Sciences, TIFR, GKVK Campus, Bellary Road, Bangalore 560065, India
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Karnawat V, Mehrotra S, Balaram H, Puranik M. Exquisite Modulation of the Active Site of Methanocaldococcus jannaschii Adenylosuccinate Synthetase in Forward Reaction Complexes. Biochemistry 2016; 55:2491-9. [PMID: 27050719 DOI: 10.1021/acs.biochem.5b01386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In enzymes that conduct complex reactions involving several substrates and chemical transformations, the active site must reorganize at each step to complement the transition state of that chemical step. Adenylosuccinate synthetase (ADSS) utilizes a molecule each of guanosine 5'-monophosphate (GTP) and aspartate to convert inosine 5'-monophosphate (IMP) into succinyl adenosine 5'-monophosphate (sAMP) through several kinetic intermediates. Here we followed catalysis by ADSS through high-resolution vibrational spectral fingerprints of each substrate and intermediate involved in the forward reaction. Vibrational spectra show differential ligand distortion at each step of catalysis, and band positions of substrates are influenced by binding of cosubstrates. We found that the bound IMP is distorted toward its N1-deprotonated form even in the absence of any other ligands. Several specific interactions between GTP and active-site amino acid residues result in large Raman shifts and contribute substantially to intrinsic binding energy. When both IMP and GTP are simultaneously bound to ADSS, IMP is converted into an intermediate 6-phosphoryl inosine 5'-monophosphate (6-pIMP). The 6-pIMP·ADSS complex was found to be stable upon binding of the third ligand, hadacidin (HDA), an analogue of l-aspartate. We find that in the absence of HDA, 6-pIMP is quickly released from ADSS, is unstable in solution, and converts back into IMP. HDA allosterically stabilizes ADSS through local conformational rearrangements. We captured this complex and determined the spectra and structure of 6-pIMP in its enzyme-bound state. These results provide important insights into the exquisite tuning of active-site interactions with changing substrate at each kinetic step of catalysis.
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Affiliation(s)
- Vishakha Karnawat
- Indian Institute of Science Education and Research , Pune 411008, India
| | - Sonali Mehrotra
- Jawaharlal Nehru Centre for Advanced Scientific Research , Jakkur, Bangalore 560064, India
| | - Hemalatha Balaram
- Jawaharlal Nehru Centre for Advanced Scientific Research , Jakkur, Bangalore 560064, India
| | - Mrinalini Puranik
- Indian Institute of Science Education and Research , Pune 411008, India
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Karnawat V, Gogia S, Balaram H, Puranik M. Differential Distortion of Purine Substrates by Human and Plasmodium falciparum Hypoxanthine-Guanine Phosphoribosyltransferase to Catalyse the Formation of Mononucleotides. Chemphyschem 2015; 16:2172-81. [PMID: 25944719 DOI: 10.1002/cphc.201500084] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Indexed: 11/10/2022]
Abstract
Plasmodium falciparum (Pf) hypoxanthine-guanine phosphoribosyltransferase (HGPRT) is a potential therapeutic target. Compared to structurally homologous human enzymes, it has expanded substrate specificity. In this study, 9-deazapurines are used as in situ probes of the active sites of human and Pf HGPRTs. Through the use of these probes it is found that non-covalent interactions stabilise the pre-transition state of the HGPRT-catalysed reaction. Vibrational spectra reveal that the bound substrates are extensively distorted, the carbonyl bond of nucleobase moiety is weakened and the substrate is destabilised along the reaction coordinate. Raman shifts of the human and Pf enzymes are used to quantify the differing degrees of hydrogen bonding in the homologues. A decreased Raman cross-section in enzyme-bound 9-deazaguanine (9DAG) shows that the phenylalanine residue (Phe186 in human and Phe197 in Pf) of HGPRT stacks with the nucleobase. Differential loss of the Raman cross-section suggests that the active site is more compact in human HGPRT as compared to the Pf enzyme, and is more so in the phosphoribosyl pyrophosphate (PRPP) complex 9DAG-PRPP-HGPRT than in 9-deazahypoxanthine (9DAH)-PRPP-HGPRT.
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Affiliation(s)
- Vishakha Karnawat
- Indian Institute of Science Education and Research, Pune-411008 (India)
| | - Spriha Gogia
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore-560065 (India)
| | - Hemalatha Balaram
- Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore-560064 (India).
| | - Mrinalini Puranik
- Indian Institute of Science Education and Research, Pune-411008 (India).
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Ceballos-Picot I, Augé F, Fu R, Olivier-Bandini A, Cahu J, Chabrol B, Aral B, de Martinville B, Lecain JP, Jinnah HA. Phenotypic variation among seven members of one family with deficiency of hypoxanthine-guanine phosphoribosyltransferase. Mol Genet Metab 2013; 110:268-74. [PMID: 24075303 PMCID: PMC3830450 DOI: 10.1016/j.ymgme.2013.08.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Revised: 08/29/2013] [Accepted: 08/29/2013] [Indexed: 11/26/2022]
Abstract
We describe a family of seven boys affected by Lesch-Nyhan disease with various phenotypes. Further investigations revealed a mutation c.203T>C in the gene encoding HGprt of all members, with substitution of leucine to proline at residue 68 (p.Leu68Pro). Thus patients from this family display a wide variety of symptoms although sharing the same mutation. Mutant HGprt enzyme was prepared by site-directed mutagenesis and the kinetics of the enzyme revealed that the catalytic activity of the mutant was reduced, in association with marked reductions in the affinity towards phosphoribosylpyrophosphate (PRPP). Its Km for PRPP was increased 215-fold with hypoxanthine as substrate and 40-fold with guanine as substrate with associated reduced catalytic potential. Molecular modeling confirmed that the most prominent defect was the dramatically reduced affinity towards PRPP. Our studies suggest that the p.Leu68Pro mutation has a strong impact on PRPP binding and on stability of the active conformation. This suggests that factors other than HGprt activity per se may influence the phenotype of Lesch-Nyhan patients.
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Affiliation(s)
- Irène Ceballos-Picot
- Department of Metabolic Biochemistry, Hôpital Necker-Enfants Malades, AP-HP, 149 rue de Sèvres, 75015 Paris, France; School of Medicine, Paris Descartes University Sorbonne Paris Cité, 15 rue de l'Ecole de Médecine, 75006 Paris, France.
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Gogia S, Puranik M. Solution structures of purine base analogues 6-chloroguanine, 8-azaguanine and allopurinol. J Biomol Struct Dyn 2013; 32:27-35. [DOI: 10.1080/07391102.2012.745821] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Narayanasamy K, Chery L, Basu A, Duraisingh MT, Escalante A, Fowble J, Guler JL, Herricks T, Kumar A, Majumder P, Maki J, Mascarenhas A, Rodrigues J, Roy B, Sen S, Shastri J, Smith J, Valecha N, White J, Rathod PK. Malaria evolution in South Asia: knowledge for control and elimination. Acta Trop 2012; 121:256-66. [PMID: 22266213 PMCID: PMC3894252 DOI: 10.1016/j.actatropica.2012.01.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Revised: 01/04/2012] [Accepted: 01/05/2012] [Indexed: 11/16/2022]
Abstract
The study of malaria parasites on the Indian subcontinent should help us understand unexpected disease outbreaks and unpredictable disease presentations from Plasmodium falciparum and Plasmodium vivax infections. The Malaria Evolution in South Asia (MESA) research program is one of ten International Centers of Excellence for Malaria Research (ICEMR) sponsored by the US National Institutes of Health. In this second of two reviews, we describe why population structures of Plasmodia in India will be characterized and how we will determine their consequences on disease presentation, outcome and patterns. Specific projects will determine if genetic diversity, possibly driven by parasites with higher genetic plasticity, plays a role in changing epidemiology, pathogenesis, vector competence of parasite populations and whether innate human genetic traits protect Indians from malaria today. Deep local clinical knowledge of malaria in India will be supplemented by basic scientists who bring new research tools. Such tools will include whole genome sequencing and analysis methods; in vitro assays to measure genome plasticity, RBC cytoadhesion, invasion, and deformability; mosquito infectivity assays to evaluate changing parasite-vector compatibilities; and host genetics to understand protective traits in Indian populations. The MESA-ICEMR study sites span diagonally across India and include a mixture of very urban and rural hospitals, each with very different disease patterns and patient populations. Research partnerships include government-associated research institutes, private medical schools, city and state government hospitals, and hospitals with industry ties. Between 2012 and 2017, in addition to developing clinical research and basic science infrastructure at new clinical sites, our training workshops will engage new scientists and clinicians throughout South Asia in the malaria research field.
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Affiliation(s)
| | - Laura Chery
- Department of Chemistry, University of Washington, Seattle, WA, USA
| | - Analabha Basu
- National Institute of Biomedical Genomics, Kalyani, West Bengal, India
| | | | | | - Joseph Fowble
- Department of Chemistry, University of Washington, Seattle, WA, USA
| | | | | | - Ashwani Kumar
- National Institute of Malaria Research (ICMR), Panaji, Goa, India
| | - Partha Majumder
- National Institute of Biomedical Genomics, Kalyani, West Bengal, India
| | - Jennifer Maki
- Department of Chemistry, University of Washington, Seattle, WA, USA
| | | | | | - Bikram Roy
- National Institute of Biomedical Genomics, Kalyani, West Bengal, India
| | - Somdutta Sen
- SphaeraPharma Research and Development, Manesar, Haryana, India
| | - Jayanthi Shastri
- Kasturba Hospital for Infectious Diseases, Mumbai, Maharashtra, India
- Topiwala Medical College & BYL Nair Hospital, Mumbai, Maharashtra, India
| | - Joseph Smith
- Seattle Biomedical Research Institute, Seattle, WA, USA
| | - Neena Valecha
- National Institute of Malaria Research (ICMR), New Delhi, India
| | - John White
- Department of Chemistry, University of Washington, Seattle, WA, USA
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