1
|
Endutkin AV, Yudkina AV, Zharkov TD, Barmatov AE, Petrova DV, Kim DV, Zharkov DO. Repair and DNA Polymerase Bypass of Clickable Pyrimidine Nucleotides. Biomolecules 2024; 14:681. [PMID: 38927084 PMCID: PMC11201982 DOI: 10.3390/biom14060681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2024] [Revised: 06/06/2024] [Accepted: 06/10/2024] [Indexed: 06/28/2024] Open
Abstract
Clickable nucleosides, most often 5-ethynyl-2'-deoxyuridine (EtU), are widely used in studies of DNA replication in living cells and in DNA functionalization for bionanotechology applications. Although clickable dNTPs are easily incorporated by DNA polymerases into the growing chain, afterwards they might become targets for DNA repair systems or interfere with faithful nucleotide insertion. Little is known about the possibility and mechanisms of these post-synthetic events. Here, we investigated the repair and (mis)coding properties of EtU and two bulkier clickable pyrimidine nucleosides, 5-(octa-1,7-diyn-1-yl)-U (C8-AlkU) and 5-(octa-1,7-diyn-1-yl)-C (C8-AlkC). In vitro, EtU and C8-AlkU, but not C8-AlkC, were excised by SMUG1 and MBD4, two DNA glycosylases from the base excision repair pathway. However, when placed into a plasmid encoding a fluorescent reporter inactivated by repair in human cells, EtU and C8-AlkU persisted for much longer than uracil or its poorly repairable phosphorothioate-flanked derivative. DNA polymerases from four different structural families preferentially bypassed EtU, C8-AlkU and C8-AlkC in an error-free manner, but a certain degree of misincorporation was also observed, especially evident for DNA polymerase β. Overall, clickable pyrimidine nucleotides could undergo repair and be a source of mutations, but the frequency of such events in the cell is unlikely to be considerable.
Collapse
Affiliation(s)
- Anton V. Endutkin
- Siberian Branch of the Russian Academy of Sciences Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., 630090 Novosibirsk, Russia; (A.V.Y.); (T.D.Z.); (A.E.B.); (D.V.P.); (D.V.K.)
| | - Anna V. Yudkina
- Siberian Branch of the Russian Academy of Sciences Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., 630090 Novosibirsk, Russia; (A.V.Y.); (T.D.Z.); (A.E.B.); (D.V.P.); (D.V.K.)
| | - Timofey D. Zharkov
- Siberian Branch of the Russian Academy of Sciences Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., 630090 Novosibirsk, Russia; (A.V.Y.); (T.D.Z.); (A.E.B.); (D.V.P.); (D.V.K.)
| | - Alexander E. Barmatov
- Siberian Branch of the Russian Academy of Sciences Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., 630090 Novosibirsk, Russia; (A.V.Y.); (T.D.Z.); (A.E.B.); (D.V.P.); (D.V.K.)
| | - Daria V. Petrova
- Siberian Branch of the Russian Academy of Sciences Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., 630090 Novosibirsk, Russia; (A.V.Y.); (T.D.Z.); (A.E.B.); (D.V.P.); (D.V.K.)
| | - Daria V. Kim
- Siberian Branch of the Russian Academy of Sciences Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., 630090 Novosibirsk, Russia; (A.V.Y.); (T.D.Z.); (A.E.B.); (D.V.P.); (D.V.K.)
| | - Dmitry O. Zharkov
- Siberian Branch of the Russian Academy of Sciences Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., 630090 Novosibirsk, Russia; (A.V.Y.); (T.D.Z.); (A.E.B.); (D.V.P.); (D.V.K.)
- Department of Natural Sciences, Novosibirsk State University, 2 Pirogova St., 630090 Novosibirsk, Russia
| |
Collapse
|
2
|
Yudkina AV, Kim DV, Zharkov TD, Zharkov DO, Endutkin AV. Probing the Conformational Restraints of DNA Damage Recognition with β-L-Nucleotides. Int J Mol Sci 2024; 25:6006. [PMID: 38892193 PMCID: PMC11172447 DOI: 10.3390/ijms25116006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2024] [Revised: 05/28/2024] [Accepted: 05/28/2024] [Indexed: 06/21/2024] Open
Abstract
The DNA building blocks 2'-deoxynucleotides are enantiomeric, with their natural β-D-configuration dictated by the sugar moiety. Their synthetic β-L-enantiomers (βLdNs) can be used to obtain L-DNA, which, when fully substituted, is resistant to nucleases and is finding use in many biosensing and nanotechnology applications. However, much less is known about the enzymatic recognition and processing of individual βLdNs embedded in D-DNA. Here, we address the template properties of βLdNs for several DNA polymerases and the ability of base excision repair enzymes to remove these modifications from DNA. The Klenow fragment was fully blocked by βLdNs, whereas DNA polymerase κ bypassed them in an error-free manner. Phage RB69 DNA polymerase and DNA polymerase β treated βLdNs as non-instructive but the latter enzyme shifted towards error-free incorporation on a gapped DNA substrate. DNA glycosylases and AP endonucleases did not process βLdNs. DNA glycosylases sensitive to the base opposite their cognate lesions also did not recognize βLdNs as a correct pairing partner. Nevertheless, when placed in a reporter plasmid, pyrimidine βLdNs were resistant to repair in human cells, whereas purine βLdNs appear to be partly repaired. Overall, βLdNs are unique modifications that are mostly non-instructive but have dual non-instructive/instructive properties in special cases.
Collapse
Affiliation(s)
- Anna V. Yudkina
- Siberian Branch of the Russian Academy of Sciences Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., 630090 Novosibirsk, Russia; (A.V.Y.); (D.V.K.); (T.D.Z.)
- Department of Natural Sciences, Novosibirsk State University, 2 Pirogova St., 630090 Novosibirsk, Russia
| | - Daria V. Kim
- Siberian Branch of the Russian Academy of Sciences Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., 630090 Novosibirsk, Russia; (A.V.Y.); (D.V.K.); (T.D.Z.)
| | - Timofey D. Zharkov
- Siberian Branch of the Russian Academy of Sciences Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., 630090 Novosibirsk, Russia; (A.V.Y.); (D.V.K.); (T.D.Z.)
| | - Dmitry O. Zharkov
- Siberian Branch of the Russian Academy of Sciences Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., 630090 Novosibirsk, Russia; (A.V.Y.); (D.V.K.); (T.D.Z.)
- Department of Natural Sciences, Novosibirsk State University, 2 Pirogova St., 630090 Novosibirsk, Russia
| | - Anton V. Endutkin
- Siberian Branch of the Russian Academy of Sciences Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., 630090 Novosibirsk, Russia; (A.V.Y.); (D.V.K.); (T.D.Z.)
| |
Collapse
|
3
|
Kim DV, Diatlova EA, Zharkov TD, Melentyev VS, Yudkina AV, Endutkin AV, Zharkov DO. Back-Up Base Excision DNA Repair in Human Cells Deficient in the Major AP Endonuclease, APE1. Int J Mol Sci 2023; 25:64. [PMID: 38203235 PMCID: PMC10778768 DOI: 10.3390/ijms25010064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 12/15/2023] [Accepted: 12/18/2023] [Indexed: 01/12/2024] Open
Abstract
Apurinic/apyrimidinic (AP) sites are abundant DNA lesions generated both by spontaneous base loss and as intermediates of base excision DNA repair. In human cells, they are normally repaired by an essential AP endonuclease, APE1, encoded by the APEX1 gene. Other enzymes can cleave AP sites by either hydrolysis or β-elimination in vitro, but it is not clear whether they provide the second line of defense in living cells. Here, we studied AP site repairs in APEX1 knockout derivatives of HEK293FT cells using a reporter system based on transcriptional mutagenesis in the enhanced green fluorescent protein gene. Despite an apparent lack of AP site-processing activity in vitro, the cells efficiently repaired the tetrahydrofuran AP site analog resistant to β-elimination. This ability persisted even when the second AP endonuclease homolog, APE2, was also knocked out. Moreover, APEX1 null cells were able to repair uracil, a DNA lesion that is removed via the formation of an AP site. If AP site hydrolysis was chemically blocked, the uracil repair required the presence of NTHL1, an enzyme that catalyzes β-elimination. Our results suggest that human cells possess at least two back-up AP site repair pathways, one of which is NTHL1-dependent.
Collapse
Affiliation(s)
- Daria V. Kim
- Siberian Branch of the Russian Academy of Sciences Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., 630090 Novosibirsk, Russia; (D.V.K.); (E.A.D.); (T.D.Z.); (V.S.M.); (A.V.Y.); (A.V.E.)
- Department of Natural Sciences, Novosibirsk State University, 2 Pirogova St., 630090 Novosibirsk, Russia
| | - Evgeniia A. Diatlova
- Siberian Branch of the Russian Academy of Sciences Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., 630090 Novosibirsk, Russia; (D.V.K.); (E.A.D.); (T.D.Z.); (V.S.M.); (A.V.Y.); (A.V.E.)
| | - Timofey D. Zharkov
- Siberian Branch of the Russian Academy of Sciences Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., 630090 Novosibirsk, Russia; (D.V.K.); (E.A.D.); (T.D.Z.); (V.S.M.); (A.V.Y.); (A.V.E.)
| | - Vasily S. Melentyev
- Siberian Branch of the Russian Academy of Sciences Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., 630090 Novosibirsk, Russia; (D.V.K.); (E.A.D.); (T.D.Z.); (V.S.M.); (A.V.Y.); (A.V.E.)
- Department of Natural Sciences, Novosibirsk State University, 2 Pirogova St., 630090 Novosibirsk, Russia
| | - Anna V. Yudkina
- Siberian Branch of the Russian Academy of Sciences Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., 630090 Novosibirsk, Russia; (D.V.K.); (E.A.D.); (T.D.Z.); (V.S.M.); (A.V.Y.); (A.V.E.)
- Department of Natural Sciences, Novosibirsk State University, 2 Pirogova St., 630090 Novosibirsk, Russia
| | - Anton V. Endutkin
- Siberian Branch of the Russian Academy of Sciences Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., 630090 Novosibirsk, Russia; (D.V.K.); (E.A.D.); (T.D.Z.); (V.S.M.); (A.V.Y.); (A.V.E.)
| | - Dmitry O. Zharkov
- Siberian Branch of the Russian Academy of Sciences Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., 630090 Novosibirsk, Russia; (D.V.K.); (E.A.D.); (T.D.Z.); (V.S.M.); (A.V.Y.); (A.V.E.)
- Department of Natural Sciences, Novosibirsk State University, 2 Pirogova St., 630090 Novosibirsk, Russia
| |
Collapse
|
4
|
Kesharwani S, Raj P, Paul A, Roy K, Bhanot A, Mehta A, Gopal A, Varshney U, Gopal B, Sundriyal S. Crystal structures of non-uracil ring fragments in complex with Mycobacterium tuberculosis uracil DNA glycosylase (MtUng) as a starting point for novel inhibitor design: A case study with the barbituric acid fragment. Eur J Med Chem 2023; 258:115604. [PMID: 37399710 DOI: 10.1016/j.ejmech.2023.115604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 06/25/2023] [Accepted: 06/25/2023] [Indexed: 07/05/2023]
Abstract
Uracil DNA glycosylase (UDG or Ung) is a key enzyme involved in uracil excision from the DNA as a repair mechanism. Designing Ung inhibitors is thus a promising strategy to treat different cancers and infectious diseases. The uracil ring and its derivatives have been shown to inhibit Mycobacterium tuberculosis Ung (MtUng), resulting from specific and strong binding with the uracil-binding pocket (UBP). To design novel MtUng inhibitors, we screened several non-uracil ring fragments hypothesised to occupy MtUng UBP due to their high similarity to the uracil structural motif. These efforts have resulted in the discovery of novel MtUng ring inhibitors. Here we report the co-crystallised poses of these fragments, confirming their binding within the UBP, thus providing a robust structural framework for the design of novel lead compounds. We selected the barbituric acid (BA) ring as a case study for further derivatisation and SAR analysis. The modelling studies predicted the BA ring of the designed analogues to interact with the MtUng UBP much like the uracil ring. The synthesised compounds were screened in vitro using radioactivity and a fluorescence-based assay. These studies led to a novel BA-based MtUng inhibitor 18a (IC50 = 300 μM) displaying ∼24-fold potency over the uracil ring.
Collapse
Affiliation(s)
- Sharyu Kesharwani
- Department of Pharmacy, Birla Institute of Technology and Science Pilani, Pilani Campus, Rajasthan, 333031, India
| | - Prateek Raj
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, 560012, India
| | - Anju Paul
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, 560012, India
| | - Koyel Roy
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, 560012, India
| | - Amritansh Bhanot
- Department of Pharmacy, Birla Institute of Technology and Science Pilani, Pilani Campus, Rajasthan, 333031, India
| | - Avani Mehta
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, 560012, India
| | - Aiswarya Gopal
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, 560012, India
| | - Umesh Varshney
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, 560012, India; Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, India
| | | | - Sandeep Sundriyal
- Department of Pharmacy, Birla Institute of Technology and Science Pilani, Pilani Campus, Rajasthan, 333031, India.
| |
Collapse
|
5
|
Diatlova EA, Mechetin GV, Yudkina AV, Zharkov VD, Torgasheva NA, Endutkin AV, Shulenina OV, Konevega AL, Gileva IP, Shchelkunov SN, Zharkov DO. Correlated Target Search by Vaccinia Virus Uracil-DNA Glycosylase, a DNA Repair Enzyme and a Processivity Factor of Viral Replication Machinery. Int J Mol Sci 2023; 24:ijms24119113. [PMID: 37298065 DOI: 10.3390/ijms24119113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 05/13/2023] [Accepted: 05/21/2023] [Indexed: 06/12/2023] Open
Abstract
The protein encoded by the vaccinia virus D4R gene has base excision repair uracil-DNA N-glycosylase (vvUNG) activity and also acts as a processivity factor in the viral replication complex. The use of a protein unlike PolN/PCNA sliding clamps is a unique feature of orthopoxviral replication, providing an attractive target for drug design. However, the intrinsic processivity of vvUNG has never been estimated, leaving open the question whether it is sufficient to impart processivity to the viral polymerase. Here, we use the correlated cleavage assay to characterize the translocation of vvUNG along DNA between two uracil residues. The salt dependence of the correlated cleavage, together with the similar affinity of vvUNG for damaged and undamaged DNA, support the one-dimensional diffusion mechanism of lesion search. Unlike short gaps, covalent adducts partly block vvUNG translocation. Kinetic experiments show that once a lesion is found it is excised with a probability ~0.76. Varying the distance between two uracils, we use a random walk model to estimate the mean number of steps per association with DNA at ~4200, which is consistent with vvUNG playing a role as a processivity factor. Finally, we show that inhibitors carrying a tetrahydro-2,4,6-trioxopyrimidinylidene moiety can suppress the processivity of vvUNG.
Collapse
Affiliation(s)
- Evgeniia A Diatlova
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., 630090 Novosibirsk, Russia
| | - Grigory V Mechetin
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., 630090 Novosibirsk, Russia
| | - Anna V Yudkina
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., 630090 Novosibirsk, Russia
| | - Vasily D Zharkov
- Biology Department, Tomsk State University, 634050 Tomsk, Russia
| | - Natalia A Torgasheva
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., 630090 Novosibirsk, Russia
| | - Anton V Endutkin
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., 630090 Novosibirsk, Russia
| | - Olga V Shulenina
- NRC "Kurchatov Institute"-B. P. Konstantinov Petersburg Nuclear Physics Institute, Leningrad Region, 188300 Gatchina, Russia
| | - Andrey L Konevega
- NRC "Kurchatov Institute"-B. P. Konstantinov Petersburg Nuclear Physics Institute, Leningrad Region, 188300 Gatchina, Russia
| | - Irina P Gileva
- State Research Center of Virology and Biotechnology Vector, Novosibirsk Region, 630559 Koltsovo, Russia
| | - Sergei N Shchelkunov
- State Research Center of Virology and Biotechnology Vector, Novosibirsk Region, 630559 Koltsovo, Russia
| | - Dmitry O Zharkov
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., 630090 Novosibirsk, Russia
- Department of Natural Sciences, Novosibirsk State University, 2 Pirogova St., 630090 Novosibirsk, Russia
| |
Collapse
|
6
|
Endutkin AV, Yudkina AV, Zharkov TD, Kim DV, Zharkov DO. Recognition of a Clickable Abasic Site Analog by DNA Polymerases and DNA Repair Enzymes. Int J Mol Sci 2022; 23:ijms232113353. [PMID: 36362137 PMCID: PMC9655677 DOI: 10.3390/ijms232113353] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Revised: 10/27/2022] [Accepted: 10/30/2022] [Indexed: 11/06/2022] Open
Abstract
Azide–alkyne cycloaddition (“click chemistry”) has found wide use in the analysis of molecular interactions in living cells. 5-ethynyl-2-(hydroxymethyl)tetrahydrofuran-3-ol (EAP) is a recently developed apurinic/apyrimidinic (AP) site analog functionalized with an ethynyl moiety, which can be introduced into cells in DNA constructs to perform labeling or cross-linking in situ. However, as a non-natural nucleoside, EAP could be subject to removal by DNA repair and misreading by DNA polymerases. Here, we investigate the interaction of this clickable AP site analog with DNA polymerases and base excision repair enzymes. Similarly to the natural AP site, EAP was non-instructive and followed the “A-rule”, directing residual but easily detectable incorporation of dAMP by E. coli DNA polymerase I Klenow fragment, bacteriophage RB69 DNA polymerase and human DNA polymerase β. On the contrary, EAP was blocking for DNA polymerases κ and λ. EAP was an excellent substrate for the major human AP endonuclease APEX1 and E. coli AP exonucleases Xth and Nfo but was resistant to the AP lyase activity of DNA glycosylases. Overall, our data indicate that EAP, once within a cell, would represent a replication block and would be removed through an AP endonuclease-initiated long-patch base excision repair pathway.
Collapse
Affiliation(s)
- Anton V. Endutkin
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., Novosibirsk 630090, Russia
- Correspondence: (A.V.E.); (D.O.Z.)
| | - Anna V. Yudkina
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., Novosibirsk 630090, Russia
| | - Timofey D. Zharkov
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., Novosibirsk 630090, Russia
| | - Daria V. Kim
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., Novosibirsk 630090, Russia
- Department of Natural Sciences, Novosibirsk State University, 2 Pirogova Street, Novosibirsk 630090, Russia
| | - Dmitry O. Zharkov
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., Novosibirsk 630090, Russia
- Department of Natural Sciences, Novosibirsk State University, 2 Pirogova Street, Novosibirsk 630090, Russia
- Correspondence: (A.V.E.); (D.O.Z.)
| |
Collapse
|
7
|
Medvedev MG, Stroganov OV, Dmitrienko AO, Panova MV, Lisov AA, Svitanko IV, Novikov FN, Chilov GG. Reducing false-positive rates in virtual screening via cancellation of systematic errors in the scoring function. MENDELEEV COMMUNICATIONS 2022. [DOI: 10.1016/j.mencom.2022.11.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
8
|
Raj P, Selvam K, Roy K, Mani Tripathi S, Kesharwani S, Gopal B, Varshney U, Sundriyal S. Identification of a new and diverse set of Mycobacterium tuberculosstais uracil-DNA glycosylase (MtUng) inhibitors using structure-based virtual screening: experimental validation and molecular dynamics studies. Bioorg Med Chem Lett 2022; 76:129008. [PMID: 36174837 DOI: 10.1016/j.bmcl.2022.129008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 09/18/2022] [Accepted: 09/23/2022] [Indexed: 11/19/2022]
Abstract
Mycobacterium tuberculosis uracil-DNA glycosylase (MtUng), a key DNA repair enzyme, represents an attractive target for the design of new antimycobacterial agents. However, only a limited number of weak MtUng inhibitors are reported, primarily based on the uracil ring, and hence, lack diversity. We report the first structure-based virtual screening (SBVS) using three separate libraries consisting of uracil and non-uracil small molecules, together with the FDA-approved drugs. Twenty diverse virtual hits with the highest predicted binding were procured and screened using a fluorescence-based assay to evaluate their potential to inhibit MtUng. Several of these molecules were found to inhibit MtUng activity at low mM and µM levels, comparable to or better than several other reported Ung inhibitors. Thus, these molecules represent a diverse set of scaffolds for developing next-generation MtUng inhibitors. The most active uracil-based compound 5 (IC50 = 0.14 mM) was found to be ∼15-fold more potent than the positive control, uracil. The binding stability and conformation of compound 5 in complex with the enzyme were further confirmed using molecular dynamics simulation.
Collapse
Affiliation(s)
- Prateek Raj
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India
| | - Karthik Selvam
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India
| | - Koyel Roy
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India
| | - Shailesh Mani Tripathi
- Department of Pharmacy, Birla Institute of Technology and Science Pilani, Pilani Campus, Rajasthan 333031, India
| | - Sharyu Kesharwani
- Department of Pharmacy, Birla Institute of Technology and Science Pilani, Pilani Campus, Rajasthan 333031, India
| | | | - Umesh Varshney
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India; Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064, India
| | - Sandeep Sundriyal
- Department of Pharmacy, Birla Institute of Technology and Science Pilani, Pilani Campus, Rajasthan 333031, India.
| |
Collapse
|