1
|
Clement PC, Sapam T, Nair DT. A conserved polar residue plays a critical role in mismatch detection in A-family DNA polymerases. Int J Biol Macromol 2024; 269:131965. [PMID: 38697428 DOI: 10.1016/j.ijbiomac.2024.131965] [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: 01/29/2024] [Revised: 04/26/2024] [Accepted: 04/27/2024] [Indexed: 05/05/2024]
Abstract
In A-family DNA polymerases (dPols), a functional 3'-5' exonuclease activity is known to proofread newly synthesized DNA. The identification of a mismatch in substrate DNA leads to transfer of the primer strand from the polymerase active site to the exonuclease active site. To shed more light regarding the mechanism responsible for the detection of mismatches, we have utilized DNA polymerase 1 from Aquifex pyrophilus (ApPol1). The enzyme synthesized DNA with high fidelity and exhibited maximal exonuclease activity with DNA substrates bearing mismatches at the -2 and - 3 positions. The crystal structure of apo-ApPol1 was utilized to generate a computational model of the functional ternary complex of this enzyme. The analysis of the model showed that N332 forms interactions with minor groove atoms of the base pairs at the -2 and - 3 positions. The majority of known A-family dPols show the presence of Asn at a position equivalent to N332. The N332L mutation led to a decrease in the exonuclease activity for representative purine-pyrimidine, and pyrimidine-pyrimidine mismatches at -2 and - 3 positions, respectively. Overall, our findings suggest that conserved polar residues located towards the minor groove may facilitate the detection of position-specific mismatches to enhance the fidelity of DNA synthesis.
Collapse
Affiliation(s)
- Patterson C Clement
- Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad 121 001, Haryana (NCR Delhi), India
| | - Tuleshwori Sapam
- Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad 121 001, Haryana (NCR Delhi), India
| | - Deepak T Nair
- Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad 121 001, Haryana (NCR Delhi), India.
| |
Collapse
|
2
|
Hengelbrock A, Schmidt A, Strube J. Digital Twin Fundamentals of mRNA In Vitro Transcription in Variable Scale Toward Autonomous Operation. ACS OMEGA 2024; 9:8204-8220. [PMID: 38405539 PMCID: PMC10882708 DOI: 10.1021/acsomega.3c08732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Revised: 01/22/2024] [Accepted: 01/26/2024] [Indexed: 02/27/2024]
Abstract
The COVID-19 pandemic caused the rapid development of mRNA (messenger ribonucleic acid) vaccines and new RNA-based therapeutic methods. However, the approval rate for candidates has the potential to be increased, with a significant number failing so far due to efficacy, safety, and manufacturing deficiencies, hindering equitable vaccine distribution during pandemics. This study focuses on optimizing the production of mRNA, a critical component of mRNA-based vaccines, using a scalable machine by investigating the key mechanisms of mRNA in vitro transcription. First, kinetic parameters for the mRNA production process were determined. The validity of the determination and the robustness of the model are demonstrated by predicting different reactions with and without substrate limitations as well as different transcripts. The optimized reaction conditions, including temperature, urea concentration, and concentration of reaction-enhancing additives, resulted in a 55% increase in mRNA yield with a 33% reduction in truncated mRNA. Additionally, the feasibility of a segmented flow approach allowed for high-throughput screening (HTS), enabling the production of 20 vaccine candidates within a short time frame, representing a 10-fold increase in productivity, compared to nonsegmented reactions limited by the residence time in the plug flow reactor. The findings presented for the first time here contribute to the development of a fully continuous and efficient manufacturing process for mRNA and other cell and gene therapy drugs/vaccine candidates as presented in our previous work, which discussed the integration of process analytical technologies and predictive process models in a Biopharma 4.0 facility to enable the production of clinical and large-scale doses, ensuring a rapid and resilient supply of critical therapeutics. The results in this study especially highlight that the same machine and equipment can be used for screening and manufacturing different drug candidates in continuous operation. By streamlining production and adhering to quality standards, this approach enhances the industry's ability to respond swiftly to pandemics and public health emergencies, addressing the urgent need for accessible and effective vaccines.
Collapse
Affiliation(s)
- Alina Hengelbrock
- Institute for Separation
and Process Technology, Clausthal University
of Technology, Clausthal-Zellerfeld 38678, Germany
| | - Axel Schmidt
- Institute for Separation
and Process Technology, Clausthal University
of Technology, Clausthal-Zellerfeld 38678, Germany
| | - Jochen Strube
- Institute for Separation
and Process Technology, Clausthal University
of Technology, Clausthal-Zellerfeld 38678, Germany
| |
Collapse
|
3
|
Buchel G, Nayak AR, Herbine K, Sarfallah A, Sokolova VO, Zamudio-Ochoa A, Temiakov D. Structural basis for DNA proofreading. Nat Commun 2023; 14:8501. [PMID: 38151585 PMCID: PMC10752894 DOI: 10.1038/s41467-023-44198-8] [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: 08/03/2023] [Accepted: 12/04/2023] [Indexed: 12/29/2023] Open
Abstract
DNA polymerase (DNAP) can correct errors in DNA during replication by proofreading, a process critical for cell viability. However, the mechanism by which an erroneously incorporated base translocates from the polymerase to the exonuclease site and the corrected DNA terminus returns has remained elusive. Here, we present an ensemble of nine high-resolution structures representing human mitochondrial DNA polymerase Gamma, Polγ, captured during consecutive proofreading steps. The structures reveal key events, including mismatched base recognition, its dissociation from the polymerase site, forward translocation of DNAP, alterations in DNA trajectory, repositioning and refolding of elements for primer separation, DNAP backtracking, and displacement of the mismatched base into the exonuclease site. Altogether, our findings suggest a conserved 'bolt-action' mechanism of proofreading based on iterative cycles of DNAP translocation without dissociation from the DNA, facilitating primer transfer between catalytic sites. Functional assays and mutagenesis corroborate this mechanism, connecting pathogenic mutations to crucial structural elements in proofreading steps.
Collapse
Affiliation(s)
- Gina Buchel
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 1020 Locust St, Philadelphia, PA, 19107, USA
| | - Ashok R Nayak
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 1020 Locust St, Philadelphia, PA, 19107, USA
| | - Karl Herbine
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 1020 Locust St, Philadelphia, PA, 19107, USA
| | - Azadeh Sarfallah
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 1020 Locust St, Philadelphia, PA, 19107, USA
| | - Viktoriia O Sokolova
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 1020 Locust St, Philadelphia, PA, 19107, USA
| | - Angelica Zamudio-Ochoa
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 1020 Locust St, Philadelphia, PA, 19107, USA
| | - Dmitry Temiakov
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 1020 Locust St, Philadelphia, PA, 19107, USA.
| |
Collapse
|
4
|
Ntallis C, Tzoupis H, Tselios T, Chasapis CT, Vlamis-Gardikas A. Distinct or Overlapping Areas of Mitochondrial Thioredoxin 2 May Be Used for Its Covalent and Strong Non-Covalent Interactions with Protein Ligands. Antioxidants (Basel) 2023; 13:15. [PMID: 38275635 PMCID: PMC10812433 DOI: 10.3390/antiox13010015] [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: 11/01/2023] [Revised: 12/09/2023] [Accepted: 12/16/2023] [Indexed: 01/27/2024] Open
Abstract
In silico approaches were employed to examine the characteristics of interactions between human mitochondrial thioredoxin 2 (HsTrx2) and its 38 previously identified mitochondrial protein ligands. All interactions appeared driven mainly by electrostatic forces. The statistically significant residues of HsTrx2 for interactions were characterized as "contact hot spots". Since these were identical/adjacent to putative thermodynamic hot spots, an energy network approach identified their neighbors to highlight possible contact interfaces. Three distinct areas for binding emerged: (i) one around the active site for covalent interactions, (ii) another antipodal to the active site for strong non-covalent interactions, and (iii) a third area involved in both kinds of interactions. The contact interfaces of HsTrx2 were projected as respective interfaces for Escherichia coli Trx1 (EcoTrx1), 2, and HsTrx1. Comparison of the interfaces and contact hot spots of HsTrx2 to the contact residues of EcoTx1 and HsTrx1 from existing crystal complexes with protein ligands supported the hypothesis, except for a part of the cleft/groove adjacent to Trp30 preceding the active site. The outcomes of this study raise the possibility for the rational design of selective inhibitors for the interactions of HsTrx2 with specific protein ligands without affecting the entirety of the functions of the Trx system.
Collapse
Affiliation(s)
- Charalampos Ntallis
- Department of Chemistry, University of Patras, 26504 Rion, Greece; (C.N.); (H.T.); (T.T.)
| | - Haralampos Tzoupis
- Department of Chemistry, University of Patras, 26504 Rion, Greece; (C.N.); (H.T.); (T.T.)
| | - Theodore Tselios
- Department of Chemistry, University of Patras, 26504 Rion, Greece; (C.N.); (H.T.); (T.T.)
| | - Christos T. Chasapis
- Institute of Chemical Biology, National Hellenic Research Foundation, Vas. Constantinou 48, 11635 Athens, Greece;
| | | |
Collapse
|
5
|
Wang X, Ma L, Li N, Gao N. Structural insights into the assembly and mechanism of mpox virus DNA polymerase complex F8-A22-E4-H5. Mol Cell 2023; 83:4398-4412.e4. [PMID: 37995690 DOI: 10.1016/j.molcel.2023.10.038] [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: 02/14/2023] [Revised: 08/21/2023] [Accepted: 09/25/2023] [Indexed: 11/25/2023]
Abstract
The DNA replication of mpox virus is performed by the viral polymerase F8 and also requires other viral factors, including processivity factor A22, uracil DNA glycosylase E4, and phosphoprotein H5. However, the molecular roles of these viral factors remain unclear. Here, we characterize the structures of F8-A22-E4 and F8-A22-E4-H5 complexes in the presence of different primer-template DNA substrates. E4 is located upstream of F8 on the template single-stranded DNA (ssDNA) and is catalytically active, highlighting a functional coupling between DNA base-excision repair and DNA synthesis. Moreover, H5, in the form of tetramer, binds to the double-stranded DNA (dsDNA) region downstream of F8 in a similar position as PCNA (proliferating cell nuclear antigen) does in eukaryotic polymerase complexes. Omission of H5 or disruption of its DNA interaction showed a reduced synthesis of full-length DNA products. These structures provide snapshots for the working cycle of the polymerase and generate insights into the mechanisms of these essential factors in viral DNA replication.
Collapse
Affiliation(s)
- Xiaohan Wang
- State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Center for Life Sciences, School of Life Sciences, Peking University, Beijing 100871, China
| | - Liangwen Ma
- State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Center for Life Sciences, School of Life Sciences, Peking University, Beijing 100871, China; Changping Laboratory, Beijing 102206, China
| | - Ningning Li
- State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Center for Life Sciences, School of Life Sciences, Peking University, Beijing 100871, China; Changping Laboratory, Beijing 102206, China.
| | - Ning Gao
- State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Center for Life Sciences, School of Life Sciences, Peking University, Beijing 100871, China; Changping Laboratory, Beijing 102206, China; National Biomedical Imaging Center, Peking University, Beijing 100871, China.
| |
Collapse
|
6
|
Yang M, Du S, Zhang Z, Xia Q, Liu H, Qin F, Wu Z, Ying H, Wu Y, Shao J, Zhao Y. Genomic diversity and biogeographic distributions of a novel lineage of bacteriophages that infect marine OM43 bacteria. Microbiol Spectr 2023; 11:e0494222. [PMID: 37607063 PMCID: PMC10580990 DOI: 10.1128/spectrum.04942-22] [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: 12/03/2022] [Accepted: 07/07/2023] [Indexed: 08/24/2023] Open
Abstract
The marine methylotrophic OM43 clade is considered an important bacterial group in coastal microbial communities. OM43 bacteria, which are closely related to phytoplankton blooms, have small cell sizes and streamlined genomes. Bacteriophages profoundly shape the evolutionary trajectories, population dynamics, and physiology of microbes. The prevalence and diversity of several phages that infect OM43 bacteria have been reported. In this study, we isolated and sequenced two novel OM43 phages, MEP401 and MEP402. These phages share 90% of their open reading frames (ORFs) and are distinct from other known phage isolates. Furthermore, a total of 99 metagenomic viral genomes (MVGs) closely related to MEP401 and MEP402 were identified. Phylogenomic analyses suggest that MEP401, MEP402, and these identified MVGs belong to a novel subfamily in the family Zobellviridae and that they can be separated into two groups. Group I MVGs show conserved whole-genome synteny with MEP401, while group II MVGs possess the MEP401-type DNA replication module and a distinct type of morphogenesis and packaging module, suggesting that genomic recombination occurred between phages. Most members in these two groups were predicted to infect OM43 bacteria. Metagenomic read-mapping analysis revealed that the phages in these two groups are globally ubiquitous and display distinct biogeographic distributions, with some phages being predominant in cold regions, some exclusively detected in estuarine stations, and others displaying wider distributions. This study expands our knowledge of the diversity and ecology of a novel phage lineage that infects OM43 bacteria by describing their genomic diversity and global distribution patterns. IMPORTANCE OM43 phages that infect marine OM43 bacteria are important for host mortality, community structure, and physiological functions. In this study, two OM43 phages were isolated and characterized. Metagenomic viral genome (MVG) retrieval using these two OM43 phages as baits led to the identification of two phage groups of a new subfamily in the family Zobellviridae. We found that group I MVGs share similar genomic content and arrangement with MEP401 and MEP402, whereas group II MVGs only possess the MEP401-type DNA replication module. Metagenomic mapping analysis suggests that members in these two groups are globally ubiquitous with distinct distribution patterns. This study provides important insights into the genomic diversity and biogeography of the OM43 phages in the global ocean.
Collapse
Affiliation(s)
- Mingyu Yang
- Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Sen Du
- Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Zefeng Zhang
- Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Qian Xia
- Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - He Liu
- Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Fang Qin
- Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Zuqing Wu
- Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Hanqi Ying
- Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Yin Wu
- Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Jiabing Shao
- Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Yanlin Zhao
- Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
- Key Laboratory of Marine Biotechnology of Fujian Province, Institute of Oceanology, Fujian Agriculture and Forestry University, Fuzhou, China
| |
Collapse
|
7
|
Johnson KA. History of advances in enzyme kinetic methods: From minutes to milliseconds. Enzymes 2023; 54:107-134. [PMID: 37945168 DOI: 10.1016/bs.enz.2023.07.005] [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] [Indexed: 11/12/2023]
Abstract
The last review on transient-state kinetic methods in The Enzymes was published three decades ago (Johnson, K.A., 1992. The Enzymes, XX, 1-61). In that review the foundations were laid out for the logic behind the design and interpretation of experiments. In the intervening years the instrumentation has improved mainly in providing better sample economy and shorter dead times. More significantly, in 1992 we were just introducing methods for fitting data based on numerical integration of rate equations, but the software was slow and difficult to use. Today, advances in numerical integration methods for data fitting have led to fast and dynamic software, making it easy to fit data without simplifying approximations. This approach overcomes multiple disadvantages of traditional data fitting based on equations derived by analytical integration of rate equations, requiring simplifying approximations. Mechanism-based fitting using computer simulation resolves mechanisms by accounting for the concentration dependence of the rates and amplitudes of the reaction to find a set of intrinsic rate constants that reproduce the experimental data, including details about how the experiment was performed in modeling the data. Rather than discuss how to design and interpret rapid-quench and stopped-flow experiments individually, we now focus on how to fit them simultaneously so that the quench-flow data anchor the interpretation of fluorescence signals. Computer simulation streamlines the fitting of multiple experiments globally to yield a single unifying model to account for all available data.
Collapse
Affiliation(s)
- Kenneth A Johnson
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, United States.
| |
Collapse
|
8
|
Sengupta A, Das K, Jha N, Akhter Y, Kumar A. Molecular evolution steered structural adaptations in the DNA polymerase III α subunit of halophilic bacterium Salinibacter ruber. Extremophiles 2023; 27:20. [PMID: 37481762 DOI: 10.1007/s00792-023-01306-2] [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: 03/14/2023] [Accepted: 07/14/2023] [Indexed: 07/25/2023]
Abstract
A significant portion of the earth has a salty environment, and the literature on bacterial survival mechanisms in salty environments is limited. During molecular evolution, halophiles increase acidic amino acid residues on their protein surfaces which leads to a negatively charged surface potential that helps them to maintain the protein integrity and protect them from denaturation by competing with salt ions. Through protein family analysis, we have investigated the molecular-level adaptive features of DNA polymerase III's catalytic subunit (alpha) and its structure-function relationship. This study throws light on the novel understanding of halophilic bacterial replication and the molecular basis of salt adaptation. Comparisons of the amino acid contents and electronegativity of halophilic and mesophilic bacterial proteins revealed adaptations that allow halophilic bacteria to thrive in high salt concentrations. A significantly lower isoelectric point of halophilic bacterial proteins indicates the acidic nature. Also, an abundance of disordered regions in halophiles suggests the requirement of the salt ions that play a crucial role in their stable protein folding. Despite having similar topology, mesophilic and halophilic proteins, a set of very prominent molecular modifications was observed in the alpha subunit of halophiles.
Collapse
Affiliation(s)
- Aveepsa Sengupta
- Department of Microbiology, Tripura University (A Central University), Suryamaninagar, Agartala, Tripura, India
| | - Kunwali Das
- Department of Microbiology, Tripura University (A Central University), Suryamaninagar, Agartala, Tripura, India
| | - Nidhi Jha
- Department of Microbiology, Tripura University (A Central University), Suryamaninagar, Agartala, Tripura, India
| | - Yusuf Akhter
- Department of Biotechnology, Babasaheb Bhimrao Ambedkar University, Vidya Vihar, Raebareli Road, Lucknow, Uttar Pradesh, 226025, India.
| | - Ashutosh Kumar
- Department of Microbiology, Tripura University (A Central University), Suryamaninagar, Agartala, Tripura, India.
| |
Collapse
|
9
|
Park J, Herrmann GK, Mitchell PG, Sherman MB, Yin YW. Polγ coordinates DNA synthesis and proofreading to ensure mitochondrial genome integrity. Nat Struct Mol Biol 2023; 30:812-823. [PMID: 37202477 PMCID: PMC10920075 DOI: 10.1038/s41594-023-00980-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 03/28/2023] [Indexed: 05/20/2023]
Abstract
Accurate replication of mitochondrial DNA (mtDNA) by DNA polymerase γ (Polγ) is essential for maintaining cellular energy supplies, metabolism, and cell cycle control. To illustrate the structural mechanism for Polγ coordinating polymerase (pol) and exonuclease (exo) activities to ensure rapid and accurate DNA synthesis, we determined four cryo-EM structures of Polγ captured after accurate or erroneous incorporation to a resolution of 2.4-3.0 Å. The structures show that Polγ employs a dual-checkpoint mechanism to sense nucleotide misincorporation and initiate proofreading. The transition from replication to error editing is accompanied by increased dynamics in both DNA and enzyme, in which the polymerase relaxes its processivity and the primer-template DNA unwinds, rotates, and backtracks to shuttle the mismatch-containing primer terminus 32 Å to the exo site for editing. Our structural and functional studies also provide a foundation for analyses of Polγ mutation-induced human diseases and aging.
Collapse
Affiliation(s)
- Joon Park
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, USA
- Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, TX, USA
| | - Geoffrey K Herrmann
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, USA
- Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, TX, USA
| | - Patrick G Mitchell
- Division of CryoEM and Bioimaging, Stanford Synchrotron Radiation Lightsource, Stanford Linear Accelerator Center National Accelerator Laboratory, Stanford University, Menlo Park, CA, USA
| | - Michael B Sherman
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, USA
- Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, TX, USA
| | - Y Whitney Yin
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, USA.
- Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, TX, USA.
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX, USA.
| |
Collapse
|
10
|
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
|
11
|
Czernecki D, Nourisson A, Legrand P, Delarue M. Reclassification of family A DNA polymerases reveals novel functional subfamilies and distinctive structural features. Nucleic Acids Res 2023; 51:4488-4507. [PMID: 37070157 PMCID: PMC10201439 DOI: 10.1093/nar/gkad242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 03/07/2023] [Accepted: 03/24/2023] [Indexed: 04/19/2023] Open
Abstract
Family A DNA polymerases (PolAs) form an important and well-studied class of extant polymerases participating in DNA replication and repair. Nonetheless, despite the characterization of multiple subfamilies in independent, dedicated works, their comprehensive classification thus far is missing. We therefore re-examine all presently available PolA sequences, converting their pairwise similarities into positions in Euclidean space, separating them into 19 major clusters. While 11 of them correspond to known subfamilies, eight had not been characterized before. For every group, we compile their general characteristics, examine their phylogenetic relationships and perform conservation analysis in the essential sequence motifs. While most subfamilies are linked to a particular domain of life (including phages), one subfamily appears in Bacteria, Archaea and Eukaryota. We also show that two new bacterial subfamilies contain functional enzymes. We use AlphaFold2 to generate high-confidence prediction models for all clusters lacking an experimentally determined structure. We identify new, conserved features involving structural alterations, ordered insertions and an apparent structural incorporation of a uracil-DNA glycosylase (UDG) domain. Finally, genetic and structural analyses of a subset of T7-like phages indicate a splitting of the 3'-5' exo and pol domains into two separate genes, observed in PolAs for the first time.
Collapse
Affiliation(s)
- Dariusz Czernecki
- Institut Pasteur, Université Paris Cité, CNRS UMR 3528, Unit of Architecture and Dynamics of Biological Macromolecules, 75015 Paris, France
- Sorbonne Université, Collège Doctoral, ED 515, 75005 Paris, France
| | - Antonin Nourisson
- Institut Pasteur, Université Paris Cité, CNRS UMR 3528, Unit of Architecture and Dynamics of Biological Macromolecules, 75015 Paris, France
- Sorbonne Université, Collège Doctoral, ED 515, 75005 Paris, France
| | - Pierre Legrand
- Institut Pasteur, Université Paris Cité, CNRS UMR 3528, Unit of Architecture and Dynamics of Biological Macromolecules, 75015 Paris, France
- Synchrotron SOLEIL, L’Orme des Merisiers, 91190 Saint-Aubin, France
| | - Marc Delarue
- Institut Pasteur, Université Paris Cité, CNRS UMR 3528, Unit of Architecture and Dynamics of Biological Macromolecules, 75015 Paris, France
| |
Collapse
|
12
|
Dangerfield TL, Johnson KA. Design and interpretation of experiments to establish enzyme pathway and define the role of conformational changes in enzyme specificity. Methods Enzymol 2023; 685:461-492. [PMID: 37245912 DOI: 10.1016/bs.mie.2023.03.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We describe the experimental methods and analysis to define the role of enzyme conformational changes in specificity based on published studies using DNA polymerases as an ideal model system. Rather than give details of how to perform transient-state and single-turnover kinetic experiments, we focus on the rationale of the experimental design and interpretation. We show how initial experiments to measure kcat and kcat/Km can accurately quantify specificity but do not define its underlying mechanistic basis. We describe methods to fluorescently label enzymes to monitor conformational changes and to correlate fluorescence signals with rapid-chemical-quench flow assays to define the steps in the pathway. Measurements of the rate of product release and of the kinetics of the reverse reaction complete the kinetic and thermodynamic description of the full reaction pathway. This analysis showed that the substrate-induced change in enzyme structure from an open to a closed state was much faster than rate-limiting chemical bond formation. However, because the reverse of the conformational change was much slower than chemistry, specificity is governed solely by the product of the binding constant for the initial weak substrate binding and the rate constant for the conformational change (kcat/Km=K1k2) so that the specificity constant does not include kcat. The enzyme conformational change leads to a closed complex in which the substrate is bound tightly and is committed to the forward reaction. In contrast, an incorrect substrate is bound weakly, and the rate of chemistry is slow, so the mismatch is released from the enzyme rapidly. Thus, the substrate-induced-fit is the major determinant of specificity. The methods outlined here should be applicable to other enzyme systems.
Collapse
Affiliation(s)
- Tyler L Dangerfield
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX, United States
| | - Kenneth A Johnson
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX, United States.
| |
Collapse
|
13
|
Chang C, Zhou G, Gao Y. In crystallo observation of active site dynamics and transient metal ion binding within DNA polymerases. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2023; 10:034702. [PMID: 37333512 PMCID: PMC10275647 DOI: 10.1063/4.0000187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Accepted: 05/31/2023] [Indexed: 06/20/2023]
Abstract
DNA polymerases are the enzymatic catalysts that synthesize DNA during DNA replication and repair. Kinetic studies and x-ray crystallography have uncovered the overall kinetic pathway and led to a two-metal-ion dependent catalytic mechanism. Diffusion-based time-resolved crystallography has permitted the visualization of the catalytic reaction at atomic resolution and made it possible to capture transient events and metal ion binding that have eluded static polymerase structures. This review discusses past static structures and recent time-resolved structures that emphasize the crucial importance of primer alignment and different metal ions binding during catalysis and substrate discrimination.
Collapse
Affiliation(s)
| | | | - Yang Gao
- Author to whom correspondence should be addressed:. Tel.: +1 (713) 348-2619
| |
Collapse
|
14
|
Stokar-Avihail A, Fedorenko T, Hör J, Garb J, Leavitt A, Millman A, Shulman G, Wojtania N, Melamed S, Amitai G, Sorek R. Discovery of phage determinants that confer sensitivity to bacterial immune systems. Cell 2023; 186:1863-1876.e16. [PMID: 37030292 DOI: 10.1016/j.cell.2023.02.029] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 01/09/2023] [Accepted: 02/20/2023] [Indexed: 04/10/2023]
Abstract
Over the past few years, numerous anti-phage defense systems have been discovered in bacteria. Although the mechanism of defense for some of these systems is understood, a major unanswered question is how these systems sense phage infection. To systematically address this question, we isolated 177 phage mutants that escape 15 different defense systems. In many cases, these escaper phages were mutated in the gene sensed by the defense system, enabling us to map the phage determinants that confer sensitivity to bacterial immunity. Our data identify specificity determinants of diverse retron systems and reveal phage-encoded triggers for multiple abortive infection systems. We find general themes in phage sensing and demonstrate that mechanistically diverse systems have converged to sense either the core replication machinery of the phage, phage structural components, or host takeover mechanisms. Combining our data with previous findings, we formulate key principles on how bacterial immune systems sense phage invaders.
Collapse
Affiliation(s)
- Avigail Stokar-Avihail
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Taya Fedorenko
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Jens Hör
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Jeremy Garb
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Azita Leavitt
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Adi Millman
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Gabriela Shulman
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Nicole Wojtania
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Sarah Melamed
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Gil Amitai
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Rotem Sorek
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel.
| |
Collapse
|
15
|
Deng S. The origin of genetic and metabolic systems: Evolutionary structuralinsights. Heliyon 2023; 9:e14466. [PMID: 36967965 PMCID: PMC10036676 DOI: 10.1016/j.heliyon.2023.e14466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 02/27/2023] [Accepted: 03/06/2023] [Indexed: 03/16/2023] Open
Abstract
DNA is derived from reverse transcription and its origin is related to reverse transcriptase, DNA polymerase and integrase. The gene structure originated from the evolution of the first RNA polymerase. Thus, an explanation of the origin of the genetic system must also explain the evolution of these enzymes. This paper proposes a polymer structure model, termed the stable complex evolution model, which explains the evolution of enzymes and functional molecules. Enzymes evolved their functions by forming locally tightly packed complexes with specific substrates. A metabolic reaction can therefore be considered to be the result of adaptive evolution in this way when a certain essential molecule is lacking in a cell. The evolution of the primitive genetic and metabolic systems was thus coordinated and synchronized. According to the stable complex model, almost all functional molecules establish binding affinity and specific recognition through complementary interactions, and functional molecules therefore have the nature of being auto-reactive. This is thermodynamically favorable and leads to functional duplication and self-organization. Therefore, it can be speculated that biological systems have a certain tendency to maintain functional stability or are influenced by an inherent selective power. The evolution of dormant bacteria may support this hypothesis, and inherent selectivity can be unified with natural selection at the molecular level.
Collapse
|
16
|
Pregeljc D, Skok J, Vodopivec T, Mencin N, Krušič A, Ličen J, Nemec KŠ, Štrancar A, Sekirnik R. Increasing yield of in vitro transcription reaction with at-line high pressure liquid chromatography monitoring. Biotechnol Bioeng 2023; 120:737-747. [PMID: 36471904 DOI: 10.1002/bit.28299] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 10/27/2022] [Accepted: 12/01/2022] [Indexed: 12/12/2022]
Abstract
The COVID-19 pandemic triggered an unprecedented rate of development of messenger ribonucleic acid (mRNA) vaccines, which are produced by in vitro transcription reactions. The latter has been the focus of intense development to increase productivity and decrease cost. Optimization of in vitro transcription (IVT) depends on understanding the impact of individual reagents on the kinetics of mRNA production and the consumption of building blocks, which is hampered by slow, low-throughput, end-point analytics. We implemented a workflow based on rapid at-line high pressure liquid chromatography (HPLC) monitoring of consumption of nucleoside triphosphates (NTPs) with concomitant production of mRNA, with a sub-3 min read-out, allowing for adjustment of IVT reaction parameters with minimal time lag. IVT was converted to fed-batch resulting in doubling the reaction yield compared to batch IVT protocol, reaching 10 mg/ml for multiple constructs. When coupled with exonuclease digestion, HPLC analytics for quantification of mRNA was extended to monitoring capping efficiency of produced mRNA. When HPLC monitoring was applied to production of an anti-reverse cap analog (ARCA)-capped mRNA construct, which requires an approximate 4:1 ARCA:guanidine triphosphate ratio, the optimized fed-batch approach achieved productivity of 9 mg/ml with 79% capping. The study provides a methodological platform for optimization of factors influencing IVT reactions, converting the reaction from batch to fed-batch mode, determining reaction kinetics, which are critical for optimization of continuous addition of reagents, thus in principle enabling continuous manufacturing of mRNA.
Collapse
Affiliation(s)
- Domen Pregeljc
- BIA Separations d.o.o., a Sartorius Company, Ajdovščina, Slovenia
| | - Janja Skok
- BIA Separations d.o.o., a Sartorius Company, Ajdovščina, Slovenia
| | - Tina Vodopivec
- BIA Separations d.o.o., a Sartorius Company, Ajdovščina, Slovenia
| | - Nina Mencin
- BIA Separations d.o.o., a Sartorius Company, Ajdovščina, Slovenia
| | - Andreja Krušič
- BIA Separations d.o.o., a Sartorius Company, Ajdovščina, Slovenia
| | - Jure Ličen
- BIA Separations d.o.o., a Sartorius Company, Ajdovščina, Slovenia
| | - Kristina Š Nemec
- BIA Separations d.o.o., a Sartorius Company, Ajdovščina, Slovenia
| | - Aleš Štrancar
- BIA Separations d.o.o., a Sartorius Company, Ajdovščina, Slovenia
| | - Rok Sekirnik
- BIA Separations d.o.o., a Sartorius Company, Ajdovščina, Slovenia
| |
Collapse
|
17
|
Plaza-G A I, Lemishko KM, Crespo R, Truong TQ, Kaguni LS, Cao-García FJ, Ciesielski GL, Ibarra B. Mechanism of strand displacement DNA synthesis by the coordinated activities of human mitochondrial DNA polymerase and SSB. Nucleic Acids Res 2023; 51:1750-1765. [PMID: 36744436 PMCID: PMC9976888 DOI: 10.1093/nar/gkad037] [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: 07/18/2022] [Revised: 12/16/2022] [Accepted: 01/12/2023] [Indexed: 02/07/2023] Open
Abstract
Many replicative DNA polymerases couple DNA replication and unwinding activities to perform strand displacement DNA synthesis, a critical ability for DNA metabolism. Strand displacement is tightly regulated by partner proteins, such as single-stranded DNA (ssDNA) binding proteins (SSBs) by a poorly understood mechanism. Here, we use single-molecule optical tweezers and biochemical assays to elucidate the molecular mechanism of strand displacement DNA synthesis by the human mitochondrial DNA polymerase, Polγ, and its modulation by cognate and noncognate SSBs. We show that Polγ exhibits a robust DNA unwinding mechanism, which entails lowering the energy barrier for unwinding of the first base pair of the DNA fork junction, by ∼55%. However, the polymerase cannot prevent the reannealing of the parental strands efficiently, which limits by ∼30-fold its strand displacement activity. We demonstrate that SSBs stimulate the Polγ strand displacement activity through several mechanisms. SSB binding energy to ssDNA additionally increases the destabilization energy at the DNA junction, by ∼25%. Furthermore, SSB interactions with the displaced ssDNA reduce the DNA fork reannealing pressure on Polγ, in turn promoting the productive polymerization state by ∼3-fold. These stimulatory effects are enhanced by species-specific functional interactions and have significant implications in the replication of the human mitochondrial DNA.
Collapse
Affiliation(s)
- Ismael Plaza-G A
- Instituto Madrileño de Estudios Avanzados en Nanociencia, IMDEA Nanociencia, Faraday 9, 28049 Madrid, Spain
| | - Kateryna M Lemishko
- Instituto Madrileño de Estudios Avanzados en Nanociencia, IMDEA Nanociencia, Faraday 9, 28049 Madrid, Spain
| | - Rodrigo Crespo
- Departamento de Estructura de la Materia, Física Térmica y Electrónica, Universidad Complutense de Madrid, Pza. de Ciencias, 1, 28040 Madrid, Spain
| | - Thinh Q Truong
- Department of Chemistry, Auburn University at Montgomery, Montgomery, AL 36117, USA
| | - Laurie S Kaguni
- Department of Biochemistry and Molecular Biology and Center for Mitochondrial Science and Medicine, Michigan State University, East Lansing, MI 48823, USA
| | - Francisco J Cao-García
- Departamento de Estructura de la Materia, Física Térmica y Electrónica, Universidad Complutense de Madrid, Pza. de Ciencias, 1, 28040 Madrid, Spain
| | - Grzegorz L Ciesielski
- Department of Chemistry, Auburn University at Montgomery, Montgomery, AL 36117, USA.,Department of Biochemistry and Molecular Biology and Center for Mitochondrial Science and Medicine, Michigan State University, East Lansing, MI 48823, USA
| | - Borja Ibarra
- Instituto Madrileño de Estudios Avanzados en Nanociencia, IMDEA Nanociencia, Faraday 9, 28049 Madrid, Spain.,Nanobiotecnología (IMDEA-Nanociencia), Unidad Asociada al Centro Nacional de Biotecnología (CSIC), 28049 Madrid, Spain
| |
Collapse
|
18
|
Primer terminal ribonucleotide alters the active site dynamics of DNA polymerase η and reduces DNA synthesis fidelity. J Biol Chem 2023; 299:102938. [PMID: 36702254 PMCID: PMC9976465 DOI: 10.1016/j.jbc.2023.102938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 01/19/2023] [Accepted: 01/20/2023] [Indexed: 01/25/2023] Open
Abstract
DNA polymerases catalyze DNA synthesis with high efficiency, which is essential for all life. Extensive kinetic and structural efforts have been executed in exploring mechanisms of DNA polymerases, surrounding their kinetic pathway, catalytic mechanisms, and factors that dictate polymerase fidelity. Recent time-resolved crystallography studies on DNA polymerase η (Pol η) and β have revealed essential transient events during the DNA synthesis reaction, such as mechanisms of primer deprotonation, separated roles of the three metal ions, and conformational changes that disfavor incorporation of the incorrect substrate. DNA-embedded ribonucleotides (rNs) are the most common lesion on DNA and a major threat to genome integrity. While kinetics of rN incorporation has been explored and structural studies have revealed that DNA polymerases have a steric gate that destabilizes ribonucleotide triphosphate binding, the mechanism of extension upon rN addition remains poorly characterized. Using steady-state kinetics, static and time-resolved X-ray crystallography with Pol η as a model system, we showed that the extra hydroxyl group on the primer terminus does alter the dynamics of the polymerase active site as well as the catalysis and fidelity of DNA synthesis. During rN extension, Pol η error incorporation efficiency increases significantly across different sequence contexts. Finally, our systematic structural studies suggest that the rN at the primer end improves primer alignment and reduces barriers in C2'-endo to C3'-endo sugar conformational change. Overall, our work provides further mechanistic insights into the effects of rN incorporation on DNA synthesis.
Collapse
|
19
|
Weaver TM, Washington MT, Freudenthal BD. New insights into DNA polymerase mechanisms provided by time-lapse crystallography. Curr Opin Struct Biol 2022; 77:102465. [PMID: 36174287 PMCID: PMC9772199 DOI: 10.1016/j.sbi.2022.102465] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 08/15/2022] [Accepted: 08/24/2022] [Indexed: 12/24/2022]
Abstract
DNA polymerases play central roles in DNA replication and repair by catalyzing template-directed nucleotide incorporation. Recently time-lapse X-ray crystallography, which allows one to observe reaction intermediates, has revealed numerous and unexpected mechanistic features of DNA polymerases. In this article, we will examine recent new discoveries that have come from time-lapse crystallography that are currently transforming our understanding of the structural mechanisms used by DNA polymerases. Among these new discoveries are the binding of a third metal ion within the polymerase active site, the mechanisms of translocation along the DNA, the presence of new fidelity checkpoints, a novel pyrophosphatase activity within the active site, and the mechanisms of pyrophosphorolysis.
Collapse
Affiliation(s)
- Tyler M Weaver
- Department of Biochemistry and Molecular Biology, Department of Cancer Biology, University of Kansas Medical Center, Kansas City, KS, 66160, USA. https://twitter.com/tylermweaver1
| | - M Todd Washington
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA.
| | - Bret D Freudenthal
- Department of Biochemistry and Molecular Biology, Department of Cancer Biology, University of Kansas Medical Center, Kansas City, KS, 66160, USA.
| |
Collapse
|
20
|
Kannan SR, Sachdev S, Reddy AS, Kandasamy SL, Byrareddy SN, Lorson CL, Singh K. Mutations in the monkeypox virus replication complex: Potential contributing factors to the 2022 outbreak. J Autoimmun 2022; 133:102928. [PMID: 36252459 PMCID: PMC9562781 DOI: 10.1016/j.jaut.2022.102928] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 10/01/2022] [Accepted: 10/07/2022] [Indexed: 11/05/2022]
Abstract
Attributes contributing to the current monkeypox virus (MPXV) outbreak remain unknown. It has been established that mutations in viral proteins may alter phenotype and pathogenicity. To assess if mutations in the MPXV DNA replication complex (RC) contribute to the outbreak, we conducted a temporal analysis of available MPXV sequences to identify mutations, generated a DNA replication complex (RC) using structures of related viral and eukaryotic proteins, and structure prediction method AlphaFold. Ten mutations within the RC were identified and mapped onto the RC to infer role of mutations. Two mutations in F8L (RC catalytic subunit), and two in G9R (a processivity factor) were ∼100% prevalent in the 2022 sequences. F8L mutation L108F emerged in 2022, whereas W411L emerged in 2018, and persisted in 2022. L108 is topologically located to enhance DNA binding affinity of F8L. Therefore, mutation L108F can change the fidelity, sensitivity to nucleoside inhibitors, and processivity of F8L. Surface exposed W411L likely affects the binding of regulatory factor(s). G9R mutations S30L and D88 N in G9R emerged in 2022, and may impact the interaction of G9R with E4R (uracil DNA glycosylase). The remaining six mutations that appeared in 2001, reverted to the first (1965 Rotterdam) isolate. Two nucleoside inhibitors brincidofovir and cidofovir have been approved for MPXV treatment. Cidofovir resistance in vaccinia virus is achieved by A314T and A684V mutations. Both A314 and A684 are conserved in MPXV. Therefore, resistance to these drugs in MPXV may arise through similar mechanisms.
Collapse
Affiliation(s)
| | - Shrikesh Sachdev
- Bond Life Sciences Center, University of Missouri, Columbia, MO, USA
| | - Athreya S. Reddy
- Bond Life Sciences Center, University of Missouri, Columbia, MO, USA
| | | | - Siddappa N. Byrareddy
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, 68198, USA,Department of Genetics, Cell Biology, and Anatomy, University of Nebraska Medical Center, Omaha, NE, 68198, USA,Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, 68198, USA,Division of Clinical Microbiology, Department of Laboratory Medicine, Karolinska Institute, Stockholm, Sweden
| | - Christian L. Lorson
- Department of Veterinary Pathobiology, University of Missouri, Columbia, MO, USA
| | - Kamal Singh
- Bond Life Sciences Center, University of Missouri, Columbia, MO, USA,Department of Veterinary Pathobiology, University of Missouri, Columbia, MO, USA,Division of Clinical Microbiology, Department of Laboratory Medicine, Karolinska Institute, Stockholm, Sweden,Corresponding author. 471g, Bond Life Sciences Center, 1201 E Rollins Street, Columbia, MO, 65211, USA
| |
Collapse
|
21
|
Kim JS, Born A, Till JKA, Liu L, Kant S, Henen MA, Vögeli B, Vázquez-Torres A. Promiscuity of response regulators for thioredoxin steers bacterial virulence. Nat Commun 2022; 13:6210. [PMID: 36266276 PMCID: PMC9584953 DOI: 10.1038/s41467-022-33983-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 10/11/2022] [Indexed: 12/24/2022] Open
Abstract
The exquisite specificity between a sensor kinase and its cognate response regulator ensures faithful partner selectivity within two-component pairs concurrently firing in a single bacterium, minimizing crosstalk with other members of this conserved family of paralogous proteins. We show that conserved hydrophobic and charged residues on the surface of thioredoxin serve as a docking station for structurally diverse response regulators. Using the OmpR protein, we identify residues in the flexible linker and the C-terminal β-hairpin that enable associations of this archetypical response regulator with thioredoxin, but are dispensable for interactions of this transcription factor to its cognate sensor kinase EnvZ, DNA or RNA polymerase. Here we show that the promiscuous interactions of response regulators with thioredoxin foster the flow of information through otherwise highly dedicated two-component signaling systems, thereby enabling both the transcription of Salmonella pathogenicity island-2 genes as well as growth of this intracellular bacterium in macrophages and mice.
Collapse
Affiliation(s)
- Ju-Sim Kim
- grid.430503.10000 0001 0703 675XUniversity of Colorado School of Medicine, Department of Immunology & Microbiology, Aurora, Colorado USA
| | - Alexandra Born
- grid.430503.10000 0001 0703 675XUniversity of Colorado School of Medicine, Department of Biochemistry & Molecular Genetics, Aurora, Colorado USA
| | - James Karl A. Till
- grid.430503.10000 0001 0703 675XUniversity of Colorado School of Medicine, Department of Immunology & Microbiology, Aurora, Colorado USA
| | - Lin Liu
- grid.430503.10000 0001 0703 675XUniversity of Colorado School of Medicine, Department of Immunology & Microbiology, Aurora, Colorado USA
| | - Sashi Kant
- grid.430503.10000 0001 0703 675XUniversity of Colorado School of Medicine, Department of Immunology & Microbiology, Aurora, Colorado USA
| | - Morkos A. Henen
- grid.430503.10000 0001 0703 675XUniversity of Colorado School of Medicine, Department of Biochemistry & Molecular Genetics, Aurora, Colorado USA ,grid.10251.370000000103426662Faculty of Pharmacy, Mansoura University, Mansoura, 35516 Egypt
| | - Beat Vögeli
- grid.430503.10000 0001 0703 675XUniversity of Colorado School of Medicine, Department of Biochemistry & Molecular Genetics, Aurora, Colorado USA
| | - Andrés Vázquez-Torres
- University of Colorado School of Medicine, Department of Immunology & Microbiology, Aurora, Colorado, USA. .,Veterans Affairs Eastern Colorado Health Care System, Denver, Colorado, USA.
| |
Collapse
|
22
|
Bubenik M, Mader P, Mochirian P, Vallée F, Clark J, Truchon JF, Perryman AL, Pau V, Kurinov I, Zahn KE, Leclaire ME, Papp R, Mathieu MC, Hamel M, Duffy NM, Godbout C, Casas-Selves M, Falgueyret JP, Baruah PS, Nicolas O, Stocco R, Poirier H, Martino G, Fortin AB, Roulston A, Chefson A, Dorich S, St-Onge M, Patel P, Pellerin C, Ciblat S, Pinter T, Barabé F, Bakkouri ME, Parikh P, Gervais C, Sfeir A, Mamane Y, Morris SJ, Black WC, Sicheri F, Gallant M. Identification of RP-6685, an Orally Bioavailable Compound that Inhibits the DNA Polymerase Activity of Polθ. J Med Chem 2022; 65:13198-13215. [PMID: 36126059 PMCID: PMC9942948 DOI: 10.1021/acs.jmedchem.2c00998] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
DNA polymerase theta (Polθ) is an attractive synthetic lethal target for drug discovery, predicted to be efficacious against breast and ovarian cancers harboring BRCA-mutant alleles. Here, we describe our hit-to-lead efforts in search of a selective inhibitor of human Polθ (encoded by POLQ). A high-throughput screening campaign of 350,000 compounds identified an 11 micromolar hit, giving rise to the N2-substituted fused pyrazolo series, which was validated by biophysical methods. Structure-based drug design efforts along with optimization of cellular potency and ADME ultimately led to the identification of RP-6685: a potent, selective, and orally bioavailable Polθ inhibitor that showed in vivo efficacy in an HCT116 BRCA2-/- mouse tumor xenograft model.
Collapse
Affiliation(s)
- Monica Bubenik
- Repare Therapeutics, 7171 Frederick-Banting, Building 2, H4S 1Z9, Montréal, Québec, Canada
| | - Pavel Mader
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, Ontario, M5G 1X5, Canada
| | - Philippe Mochirian
- Repare Therapeutics, 7171 Frederick-Banting, Building 2, H4S 1Z9, Montréal, Québec, Canada
| | - Fréderic Vallée
- Repare Therapeutics, 7171 Frederick-Banting, Building 2, H4S 1Z9, Montréal, Québec, Canada
| | - Jillian Clark
- Repare Therapeutics, 7171 Frederick-Banting, Building 2, H4S 1Z9, Montréal, Québec, Canada
| | - Jean-François Truchon
- Repare Therapeutics, 7171 Frederick-Banting, Building 2, H4S 1Z9, Montréal, Québec, Canada
| | - Alexander L. Perryman
- Repare Therapeutics, 7171 Frederick-Banting, Building 2, H4S 1Z9, Montréal, Québec, Canada
| | - Victor Pau
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, Ontario, M5G 1X5, Canada
| | - Igor Kurinov
- Department of Chemistry and Chemical Biology, Cornell University, NE-CAT, Argonne, Illinois 60439, USA
| | - Karl E. Zahn
- Repare Therapeutics, 7171 Frederick-Banting, Building 2, H4S 1Z9, Montréal, Québec, Canada
| | - Marie-Eve Leclaire
- Repare Therapeutics, 7171 Frederick-Banting, Building 2, H4S 1Z9, Montréal, Québec, Canada
| | - Robert Papp
- Repare Therapeutics, 7171 Frederick-Banting, Building 2, H4S 1Z9, Montréal, Québec, Canada
| | - Marie-Claude Mathieu
- Repare Therapeutics, 7171 Frederick-Banting, Building 2, H4S 1Z9, Montréal, Québec, Canada
| | - Martine Hamel
- Repare Therapeutics, 7171 Frederick-Banting, Building 2, H4S 1Z9, Montréal, Québec, Canada
| | - Nicole M. Duffy
- Repare Therapeutics, 7171 Frederick-Banting, Building 2, H4S 1Z9, Montréal, Québec, Canada
| | - Claude Godbout
- Repare Therapeutics, 7171 Frederick-Banting, Building 2, H4S 1Z9, Montréal, Québec, Canada
| | - Matias Casas-Selves
- Repare Therapeutics, 7171 Frederick-Banting, Building 2, H4S 1Z9, Montréal, Québec, Canada
| | - Jean-Pierre Falgueyret
- Repare Therapeutics, 7171 Frederick-Banting, Building 2, H4S 1Z9, Montréal, Québec, Canada
| | - Prasamit S. Baruah
- Repare Therapeutics, 7171 Frederick-Banting, Building 2, H4S 1Z9, Montréal, Québec, Canada
| | - Olivier Nicolas
- Repare Therapeutics, 7171 Frederick-Banting, Building 2, H4S 1Z9, Montréal, Québec, Canada
| | - Rino Stocco
- Repare Therapeutics, 7171 Frederick-Banting, Building 2, H4S 1Z9, Montréal, Québec, Canada
| | - Hugo Poirier
- Repare Therapeutics, 7171 Frederick-Banting, Building 2, H4S 1Z9, Montréal, Québec, Canada
| | - Giovanni Martino
- Repare Therapeutics, 7171 Frederick-Banting, Building 2, H4S 1Z9, Montréal, Québec, Canada
| | | | - Anne Roulston
- Repare Therapeutics, 7171 Frederick-Banting, Building 2, H4S 1Z9, Montréal, Québec, Canada
| | - Amandine Chefson
- Ventus Therapeutics 7150 Frederick-Banting suite 200, Montréal, Québec, H4S 2A1, Canada
| | - Stéphane Dorich
- Ventus Therapeutics 7150 Frederick-Banting suite 200, Montréal, Québec, H4S 2A1, Canada
| | - Miguel St-Onge
- Ventus Therapeutics 7150 Frederick-Banting suite 200, Montréal, Québec, H4S 2A1, Canada
| | - Purvish Patel
- Ventus Therapeutics 7150 Frederick-Banting suite 200, Montréal, Québec, H4S 2A1, Canada
| | - Charles Pellerin
- Ventus Therapeutics 7150 Frederick-Banting suite 200, Montréal, Québec, H4S 2A1, Canada
| | - Stéphane Ciblat
- Ventus Therapeutics 7150 Frederick-Banting suite 200, Montréal, Québec, H4S 2A1, Canada
- Paraza Pharma Inc., 2525 Ave. Marie Curie, Montréal, Québec, H4S 1Z9, Canada
| | - Thomas Pinter
- Paraza Pharma Inc., 2525 Ave. Marie Curie, Montréal, Québec, H4S 1Z9, Canada
| | - Francis Barabé
- Paraza Pharma Inc., 2525 Ave. Marie Curie, Montréal, Québec, H4S 1Z9, Canada
| | - Majida El Bakkouri
- Paraza Pharma Inc., 2525 Ave. Marie Curie, Montréal, Québec, H4S 1Z9, Canada
- National Research Council of Canada, 6100 Royalmount Ave, Montréal, Québec, H4P 2R2, Canada
| | - Paranjay Parikh
- Piramal Pharma Ltd., Plot No. 18, Village Matoda, Taluka: Sanand, Ahmedabad-382213, Gujarat, India
| | - Christian Gervais
- National Research Council of Canada, 6100 Royalmount Ave, Montréal, Québec, H4P 2R2, Canada
| | - Agnel Sfeir
- Molecular Biology Program, Sloan Kettering Institute, MSKCC, 430 E 67th Street, New York, NY 10065, USA
| | - Yael Mamane
- Repare Therapeutics, 7171 Frederick-Banting, Building 2, H4S 1Z9, Montréal, Québec, Canada
| | - Stephen J. Morris
- Repare Therapeutics, 7171 Frederick-Banting, Building 2, H4S 1Z9, Montréal, Québec, Canada
| | - W. Cameron Black
- Repare Therapeutics, 7171 Frederick-Banting, Building 2, H4S 1Z9, Montréal, Québec, Canada
| | - Frank Sicheri
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, Ontario, M5G 1X5, Canada
| | - Michel Gallant
- Repare Therapeutics, 7171 Frederick-Banting, Building 2, H4S 1Z9, Montréal, Québec, Canada
| |
Collapse
|
23
|
Wang J, Shi Y, Reiss K, Maschietto F, Lolis E, Konigsberg WH, Lisi GP, Batista VS. Structural Insights into Binding of Remdesivir Triphosphate within the Replication-Transcription Complex of SARS-CoV-2. Biochemistry 2022; 61:1966-1973. [PMID: 36044776 PMCID: PMC9469760 DOI: 10.1021/acs.biochem.2c00341] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 08/18/2022] [Indexed: 01/18/2023]
Abstract
Remdesivir is an adenosine analogue that has a cyano substitution in the C1' position of the ribosyl moiety and a modified base structure to stabilize the linkage of the base to the C1' atom with its strong electron-withdrawing cyano group. Within the replication-transcription complex (RTC) of SARS-CoV-2, the RNA-dependent RNA polymerase nsp12 selects remdesivir monophosphate (RMP) over adenosine monophosphate (AMP) for nucleotide incorporation but noticeably slows primer extension after the added RMP of the RNA duplex product is translocated by three base pairs. Cryo-EM structures have been determined for the RTC with RMP at the nucleotide-insertion (i) site or at the i + 1, i + 2, or i + 3 sites after product translocation to provide a structural basis for a delayed-inhibition mechanism by remdesivir. In this study, we applied molecular dynamics (MD) simulations to extend the resolution of structures to the measurable maximum that is intrinsically limited by MD properties of these complexes. Our MD simulations provide (i) a structural basis for nucleotide selectivity of the incoming substrates of remdesivir triphosphate over adenosine triphosphate and of ribonucleotide over deoxyribonucleotide, (ii) new detailed information on hydrogen atoms involved in H-bonding interactions between the enzyme and remdesivir, and (iii) direct information on the catalytically active complex that is not easily captured by experimental methods. Our improved resolution of interatomic interactions at the nucleotide-binding pocket between remedesivir and the polymerase could help to design a new class of anti-SARS-CoV-2 inhibitors.
Collapse
Affiliation(s)
- Jimin Wang
- Department
of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520-8114, United States
| | - Yuanjun Shi
- Department
of Chemistry, Yale University, New Haven, Connecticut 06520-8499, United States
| | - Krystle Reiss
- Department
of Chemistry, Yale University, New Haven, Connecticut 06520-8499, United States
| | - Federica Maschietto
- Department
of Chemistry, Yale University, New Haven, Connecticut 06520-8499, United States
| | - Elias Lolis
- Department
of Pharmacology, Yale University, New Haven, Connecticut 06520-8066, United States
| | - William H. Konigsberg
- Department
of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520-8114, United States
| | - George P. Lisi
- Department
of Molecular and Cell Biology and Biochemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Victor S. Batista
- Department
of Chemistry, Yale University, New Haven, Connecticut 06520-8499, United States
| |
Collapse
|
24
|
Antika TR, Nazilah KR, Lee YH, Lo YT, Yeh CS, Yeh FL, Chang TH, Wang TL, Wang CC. Human Thg1 displays tRNA-inducible GTPase activity. Nucleic Acids Res 2022; 50:10015-10025. [PMID: 36107775 PMCID: PMC9508852 DOI: 10.1093/nar/gkac768] [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: 07/23/2022] [Revised: 08/22/2022] [Accepted: 08/26/2022] [Indexed: 11/13/2022] Open
Abstract
tRNAHis guanylyltransferase (Thg1) catalyzes the 3′-5′ incorporation of guanosine into position -1 (G-1) of tRNAHis. G-1 is unique to tRNAHis and is crucial for recognition by histidyl-tRNA synthetase (HisRS). Yeast Thg1 requires ATP for G-1 addition to tRNAHis opposite A73, whereas archaeal Thg1 requires either ATP or GTP for G-1 addition to tRNAHis opposite C73. Paradoxically, human Thg1 (HsThg1) can add G-1 to tRNAsHis with A73 (cytoplasmic) and C73 (mitochondrial). As N73 is immediately followed by a CCA end (positions 74–76), how HsThg1 prevents successive 3′-5′ incorporation of G-1/G-2/G-3 into mitochondrial tRNAHis (tRNAmHis) through a template-dependent mechanism remains a puzzle. We showed herein that mature native human tRNAmHis indeed contains only G-1. ATP was absolutely required for G-1 addition to tRNAmHis by HsThg1. Although HsThg1 could incorporate more than one GTP into tRNAmHisin vitro, a single-GTP incorporation prevailed when the relative GTP level was low. Surprisingly, HsThg1 possessed a tRNA-inducible GTPase activity, which could be inhibited by ATP. Similar activity was found in other high-eukaryotic dual-functional Thg1 enzymes, but not in yeast Thg1. This study suggests that HsThg1 may downregulate the level of GTP through its GTPase activity to prevent multiple-GTP incorporation into tRNAmHis.
Collapse
Affiliation(s)
- Titi Rindi Antika
- Department of Life Sciences, National Central University , Zhongli District, Taoyuan 320317, Taiwan
| | - Kun Rohmatan Nazilah
- Department of Life Sciences, National Central University , Zhongli District, Taoyuan 320317, Taiwan
| | - Yi-Hsueh Lee
- Department of Life Sciences, National Central University , Zhongli District, Taoyuan 320317, Taiwan
| | - Ya-Ting Lo
- Department of Life Sciences, National Central University , Zhongli District, Taoyuan 320317, Taiwan
| | - Chung-Shu Yeh
- Genomics Research Center , Academia Sinica, Nankang District, Taipei 11529, Taiwan
| | - Fu-Lung Yeh
- Genomics Research Center , Academia Sinica, Nankang District, Taipei 11529, Taiwan
| | - Tien-Hsien Chang
- Genomics Research Center , Academia Sinica, Nankang District, Taipei 11529, Taiwan
| | - Tzu-Ling Wang
- Graduate Institute of Mathematics and Science Education, National Tsing Hua University , Hsinchu City 30014, Taiwan
| | - Chien-Chia Wang
- Department of Life Sciences, National Central University , Zhongli District, Taoyuan 320317, Taiwan
| |
Collapse
|
25
|
Lim Y, Park IH, Lee HH, Baek K, Lee BC, Cho G. Modified Taq polymerase for allele-specific ultra-sensitive detection of genetic variants. J Mol Diagn 2022; 24:1128-1142. [PMID: 36058471 DOI: 10.1016/j.jmoldx.2022.08.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 07/28/2022] [Accepted: 08/11/2022] [Indexed: 11/30/2022] Open
Abstract
Allele-specific polymerase chain reaction (AS-PCR) has been used as a simple, cost-effective method for genotyping and gene mapping in research and clinical settings. AS-PCR permits the detection of single nucleotide variants (SNVs) and indels owing to the selective extension of a perfectly matched primer (to the template DNA) over a mismatched primer. Thus, the mismatch discrimination power of the DNA polymerase is critical. Unfortunately, currently available polymerases often amplify some mismatched primer-template complexes as well as matched ones, obscuring allele-specific detection. To increase mismatch discrimination, we have generated mutations in the Thermus aquaticus (Taq) DNA polymerase, selected the most efficient variant, and evaluated its performance in SNP and cancer mutation genotyping. In addition, the primer design and reaction buffer conditions were optimized for allele-specific amplification. Our highly selective AS-PCR, which is based on an allele-discriminating priming system (ADPS) that leverages a Taq polymerase variant with optimized primers and reaction buffer, can detect mutations with mutant allele frequency as low as 0.01% in genomic DNA and 0.0001% in plasmid DNA. This method serves as a simple, fast, cost-effective, and ultra-sensitive way to detect SNVs and indels with low abundance.
Collapse
Affiliation(s)
- Youngshin Lim
- Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Il-Hyun Park
- GENECAST, 66 Chungmin-ro, Songpa-gu, Seoul, KOREA
| | - Huy-Ho Lee
- GENECAST, 66 Chungmin-ro, Songpa-gu, Seoul, KOREA
| | - Kyuwon Baek
- GENECAST, 66 Chungmin-ro, Songpa-gu, Seoul, KOREA
| | | | - Ginam Cho
- Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
| |
Collapse
|
26
|
Pata JD, Yin YW, Lahiri I. Editorial: Nucleic Acid Polymerases: The Two-Metal-Ion Mechanism and Beyond. Front Mol Biosci 2022; 9:948326. [PMID: 35911968 PMCID: PMC9332193 DOI: 10.3389/fmolb.2022.948326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Accepted: 06/16/2022] [Indexed: 11/13/2022] Open
Affiliation(s)
- Janice D. Pata
- Wadsworth Center, New York State Department of Health, Albany, NY, United States
- Department of Biomedical Sciences, School of Public Health, University at Albany, Albany, NY, United States
- *Correspondence: Janice D. Pata,
| | - Y. Whitney Yin
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, United States
| | - Indrajit Lahiri
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Punjab, India
| |
Collapse
|
27
|
Residues located in the primase domain of the bacteriophage T7 primase-helicase are essential for loading the hexameric complex onto DNA. J Biol Chem 2022; 298:101996. [PMID: 35500649 PMCID: PMC9198812 DOI: 10.1016/j.jbc.2022.101996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 04/25/2022] [Accepted: 04/26/2022] [Indexed: 11/24/2022] Open
Abstract
The T7 primase-helicase plays a pivotal role in the replication of T7 DNA. Using affinity isolation of peptide–nucleic acid crosslinks and mass spectrometry, we identify protein regions in the primase-helicase and T7 DNA polymerase that form contacts with the RNA primer and DNA template. The contacts between nucleic acids and the primase domain of the primase-helicase are centered in the RNA polymerase subdomain of the primase domain, in a cleft between the N-terminal subdomain and the topoisomerase-primase fold. We demonstrate that residues along a beta sheet in the N-terminal subdomain that contacts the RNA primer are essential for phage growth and primase activity in vitro. Surprisingly, we found mutations in the primase domain that had a dramatic effect on the helicase. Substitution of a residue conserved in other DnaG-like enzymes, R84A, abrogates both primase and helicase enzymatic activities of the T7 primase-helicase. Alterations in this residue also decrease binding of the primase-helicase to ssDNA. However, mass photometry measurements show that these mutations do not interfere with the ability of the protein to form the active hexamer.
Collapse
|
28
|
Millar DP. Conformational Dynamics of DNA Polymerases Revealed at the Single-Molecule Level. Front Mol Biosci 2022; 9:826593. [PMID: 35281261 PMCID: PMC8913937 DOI: 10.3389/fmolb.2022.826593] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 01/20/2022] [Indexed: 12/25/2022] Open
Abstract
DNA polymerases are intrinsically dynamic macromolecular machines. The purpose of this review is to describe the single-molecule Förster resonance energy transfer (smFRET) methods that are used to probe the conformational dynamics of DNA polymerases, focusing on E. coli DNA polymerase I. The studies reviewed here reveal the conformational dynamics underpinning the nucleotide selection, proofreading and 5′ nuclease activities of Pol I. Moreover, the mechanisms revealed for Pol I are likely employed across the DNA polymerase family. smFRET methods have also been used to examine other aspects of DNA polymerase activity.
Collapse
|
29
|
Carvajal-Maldonado D, Drogalis Beckham L, Wood RD, Doublié S. When DNA Polymerases Multitask: Functions Beyond Nucleotidyl Transfer. Front Mol Biosci 2022; 8:815845. [PMID: 35071329 PMCID: PMC8782244 DOI: 10.3389/fmolb.2021.815845] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 12/13/2021] [Indexed: 11/13/2022] Open
Abstract
DNA polymerases catalyze nucleotidyl transfer, the central reaction in synthesis of DNA polynucleotide chains. They function not only in DNA replication, but also in diverse aspects of DNA repair and recombination. Some DNA polymerases can perform translesion DNA synthesis, facilitating damage tolerance and leading to mutagenesis. In addition to these functions, many DNA polymerases conduct biochemically distinct reactions. This review presents examples of DNA polymerases that carry out nuclease (3'-5' exonuclease, 5' nuclease, or end-trimming nuclease) or lyase (5' dRP lyase) extracurricular activities. The discussion underscores how DNA polymerases have a remarkable ability to manipulate DNA strands, sometimes involving relatively large intramolecular movement.
Collapse
Affiliation(s)
- Denisse Carvajal-Maldonado
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Center, Houston, TX, United States
| | - Lea Drogalis Beckham
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, VT, United States
| | - Richard D Wood
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Center, Houston, TX, United States
| | - Sylvie Doublié
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, VT, United States
| |
Collapse
|
30
|
DNA Polymerase-Parental DNA Interaction Is Essential for Helicase-Polymerase Coupling during Bacteriophage T7 DNA Replication. Int J Mol Sci 2022; 23:ijms23031342. [PMID: 35163266 PMCID: PMC8835902 DOI: 10.3390/ijms23031342] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 01/19/2022] [Accepted: 01/22/2022] [Indexed: 11/17/2022] Open
Abstract
DNA helicase and polymerase work cooperatively at the replication fork to perform leading-strand DNA synthesis. It was believed that the helicase migrates to the forefront of the replication fork where it unwinds the duplex to provide templates for DNA polymerases. However, the molecular basis of the helicase-polymerase coupling is not fully understood. The recently elucidated T7 replisome structure suggests that the helicase and polymerase sandwich parental DNA and each enzyme pulls a daughter strand in opposite directions. Interestingly, the T7 polymerase, but not the helicase, carries the parental DNA with a positively charged cleft and stacks at the fork opening using a β-hairpin loop. Here, we created and characterized T7 polymerases each with a perturbed β-hairpin loop and positively charged cleft. Mutations on both structural elements significantly reduced the strand-displacement synthesis by T7 polymerase but had only a minor effect on DNA synthesis performed against a linear DNA substrate. Moreover, the aforementioned mutations eliminated synergistic helicase-polymerase binding and unwinding at the DNA fork and processive fork progressions. Thus, our data suggested that T7 polymerase plays a dominant role in helicase-polymerase coupling and replisome progression.
Collapse
|
31
|
Lo CY, Gao Y. Assembling bacteriophage T7 leading-strand replisome for structural investigation. Methods Enzymol 2022; 672:103-123. [PMID: 35934471 DOI: 10.1016/bs.mie.2022.03.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Replicative helicase and polymerase form the leading-strand replisome that unwinds parental DNA and performs continuous leading-strand DNA synthesis. Uncoupling of the helicase-polymerase complex results in replication stress, replication errors, and genome instability. Although numerous replisomes from different biological systems have been reconstituted and characterized, structural investigations of the leading-strand replisome complex are hindered by its large size and dynamics. We have determined the first replisome structure on a fork substrate with bacteriophage T7 replisome as a model system. Here, we summarized our protocols to prepare and characterize the coupled T7 replisome complex. Similar methods can potentially be applied for structural investigations of more complicated replisomes.
Collapse
|
32
|
Singh A, Patel SS. Quantitative methods to study helicase, DNA polymerase, and exonuclease coupling during DNA replication. Methods Enzymol 2022; 672:75-102. [PMID: 35934486 PMCID: PMC9933136 DOI: 10.1016/bs.mie.2022.03.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Genome replication is accomplished by highly regulated activities of enzymes in a multi-protein complex called the replisome. Two major enzymes, DNA polymerase and helicase, catalyze continuous DNA synthesis on the leading strand of the parental DNA duplex while the lagging strand is synthesized discontinuously. The helicase and DNA polymerase on their own are catalytically inefficient and weak motors for unwinding/replicating double-stranded DNA. However, when a helicase and DNA polymerase are functionally and physically coupled, they catalyze fast and highly processive leading strand DNA synthesis. DNA polymerase has a 3'-5' exonuclease activity, which removes nucleotides misincorporated in the nascent DNA. DNA synthesis kinetics, processivity, and accuracy are governed by the interplay of the helicase, DNA polymerase, and exonuclease activities within the replisome. This chapter describes quantitative biochemical and biophysical methods to study the coupling of these three critical activities during DNA replication. The methods include real-time quantitation of kinetics of DNA unwinding-synthesis by a coupled helicase-DNA polymerase complex, a 2-aminopurine fluorescence-based assay to map the precise positions of helicase and DNA polymerase with respect to the replication fork junction, and a radiometric assay to study the coupling of DNA polymerase, exonuclease, and helicase activities during processive leading strand DNA synthesis. These methods are presented here with bacteriophage T7 replication proteins as an example but can be applied to other systems with appropriate modifications.
Collapse
|
33
|
Dangerfield TL, Kirmizialtin S, Johnson KA. Conformational dynamics during misincorporation and mismatch extension defined using a DNA polymerase with a fluorescent artificial amino acid. J Biol Chem 2021; 298:101451. [PMID: 34838820 PMCID: PMC8715121 DOI: 10.1016/j.jbc.2021.101451] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 09/09/2021] [Accepted: 11/23/2021] [Indexed: 11/29/2022] Open
Abstract
High-fidelity DNA polymerases select the correct nucleotide over the structurally similar incorrect nucleotides with extremely high specificity while maintaining fast rates of incorporation. Previous analysis revealed the conformational dynamics and complete kinetic pathway governing correct nucleotide incorporation using a high-fidelity DNA polymerase variant containing a fluorescent unnatural amino acid. Here we extend this analysis to investigate the kinetics of nucleotide misincorporation and mismatch extension. We report the specificity constants for all possible misincorporations and characterize the conformational dynamics of the enzyme during misincorporation and mismatch extension. We present free energy profiles based on the kinetic measurements and discuss the effect of different steps on specificity. During mismatch incorporation and subsequent extension with the correct nucleotide, the rates of the conformational change and chemistry are both greatly reduced. The nucleotide dissociation rate, however, increases to exceed the rate of chemistry. To investigate the structural basis for discrimination against mismatched nucleotides, we performed all atom molecular dynamics simulations on complexes with either the correct or mismatched nucleotide bound at the polymerase active site. The simulations suggest that the closed form of the enzyme with a mismatch bound is greatly destabilized due to weaker interactions with active site residues, nonideal base pairing, and a large increase in the distance from the 3'-OH group of the primer strand to the α-phosphate of the incoming nucleotide, explaining the reduced rates of misincorporation. The observed kinetic and structural mechanisms governing nucleotide misincorporation reveal the general principles likely applicable to other high-fidelity DNA polymerases.
Collapse
Affiliation(s)
- Tyler L Dangerfield
- Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, University of Texas, Austin, Texas, USA
| | - Serdal Kirmizialtin
- Chemistry Program, Division of Science, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Kenneth A Johnson
- Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, University of Texas, Austin, Texas, USA.
| |
Collapse
|
34
|
Czernecki D, Hu H, Romoli F, Delarue M. Structural dynamics and determinants of 2-aminoadenine specificity in DNA polymerase DpoZ of vibriophage ϕVC8. Nucleic Acids Res 2021; 49:11974-11985. [PMID: 34751404 PMCID: PMC8599892 DOI: 10.1093/nar/gkab955] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 09/29/2021] [Accepted: 10/04/2021] [Indexed: 11/12/2022] Open
Abstract
All genetic information in cellular life is stored in DNA copolymers composed of four basic building blocks (ATGC-DNA). In contrast, a group of bacteriophages belonging to families Siphoviridae and Podoviridae has abandoned the usage of one of them, adenine (A), replacing it with 2-aminoadenine (Z). The resulting ZTGC-DNA is more stable than its ATGC-DNA counterpart, owing to the additional hydrogen bond present in the 2-aminoadenine:thymine (Z:T) base pair, while the additional amino group also confers resistance to the host endonucleases. Recently, two classes of replicative proteins found in ZTGC-DNA-containing phages were characterized and one of them, DpoZ from DNA polymerase A (PolA) family, was shown to possess significant Z-vs-A specificity. Here, we present the crystallographic structure of the apo form of DpoZ of vibriophage ϕVC8, composed of the 3′-5′ exonuclease and polymerase domains. We captured the enzyme in two conformations that involve the tip of the thumb subdomain and the exonuclease domain. We highlight insertions and mutations characteristic of ϕVC8 DpoZ and its close homologues. Through mutagenesis and functional assays we suggest that the preference of ϕVC8 DpoZ towards Z relies on a polymerase backtracking process, more efficient when the nascent base pair is A:T than when it is Z:T.
Collapse
Affiliation(s)
- Dariusz Czernecki
- Unit of Architecture and Dynamics of Biological Macromolecules, CNRS UMR 3528, 25-28 rue du Docteur Roux, Institut Pasteur, 75015 Paris, France.,Sorbonne Université, Collège Doctoral, ED 515, 75005 Paris, France
| | - Haidai Hu
- Unit of Architecture and Dynamics of Biological Macromolecules, CNRS UMR 3528, 25-28 rue du Docteur Roux, Institut Pasteur, 75015 Paris, France
| | - Filippo Romoli
- Unit of Architecture and Dynamics of Biological Macromolecules, CNRS UMR 3528, 25-28 rue du Docteur Roux, Institut Pasteur, 75015 Paris, France
| | - Marc Delarue
- Unit of Architecture and Dynamics of Biological Macromolecules, CNRS UMR 3528, 25-28 rue du Docteur Roux, Institut Pasteur, 75015 Paris, France
| |
Collapse
|
35
|
Kazantsev A, Ignatova Z. Constraints on error rate revealed by computational study of G•U tautomerization in translation. Nucleic Acids Res 2021; 49:11823-11833. [PMID: 34669948 PMCID: PMC8599798 DOI: 10.1093/nar/gkab947] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 09/30/2021] [Accepted: 10/01/2021] [Indexed: 11/18/2022] Open
Abstract
In translation, G•U mismatch in codon-anticodon decoding is an error hotspot likely due to transition of G•U from wobble (wb) to Watson-Crick (WC) geometry, which is governed by keto/enol tautomerization (wb-WC reaction). Yet, effects of the ribosome on the wb-WC reaction and its implications for decoding mechanism remain unclear. Employing quantum-mechanical/molecular-mechanical umbrella sampling simulations using models of the ribosomal decoding site (A site) we determined that the wb-WC reaction is endoergic in the open, but weakly exoergic in the closed A-site state. We extended the classical ‘induced-fit’ model of initial selection by incorporating wb-WC reaction parameters in open and closed states. For predicted parameters, the non-equilibrium exoergic wb-WC reaction is kinetically limited by the decoding rates. The model explains early observations of the WC geometry of G•U from equilibrium structural studies and reveals discrimination capacity for the working ribosome operating at non-equilibrium conditions. The equilibration of the exoergic wb-WC reaction counteracts the equilibration of the open-closed transition of the A site, constraining the decoding accuracy and potentially explaining the persistence of the G•U as an error hotspot. Our results unify structural and mechanistic views of codon-anticodon decoding and generalize the ‘induced-fit’ model for flexible substrates.
Collapse
Affiliation(s)
- Andriy Kazantsev
- Institute of Biochemistry and Molecular Biology, Department of Chemistry, University of Hamburg, Martin-Luther-King-Platz 6, 20146 Hamburg, Germany
| | - Zoya Ignatova
- Institute of Biochemistry and Molecular Biology, Department of Chemistry, University of Hamburg, Martin-Luther-King-Platz 6, 20146 Hamburg, Germany
| |
Collapse
|
36
|
Geronimo I, Vidossich P, De Vivo M. Local Structural Dynamics at the Metal-Centered Catalytic Site of Polymerases is Critical for Fidelity. ACS Catal 2021. [DOI: 10.1021/acscatal.1c03840] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Inacrist Geronimo
- Laboratory of Molecular Modelling & Drug Discovery, Istituto Italiano di Tecnologia, Via Morego 30, Genoa 16163, Italy
| | - Pietro Vidossich
- Laboratory of Molecular Modelling & Drug Discovery, Istituto Italiano di Tecnologia, Via Morego 30, Genoa 16163, Italy
| | - Marco De Vivo
- Laboratory of Molecular Modelling & Drug Discovery, Istituto Italiano di Tecnologia, Via Morego 30, Genoa 16163, Italy
| |
Collapse
|
37
|
Sonohara Y, Takatsuka R, Masutani C, Iwai S, Kuraoka I. Acetaldehyde induces NER repairable mutagenic DNA lesions. Carcinogenesis 2021; 43:52-59. [PMID: 34546339 DOI: 10.1093/carcin/bgab087] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 09/14/2021] [Accepted: 09/17/2021] [Indexed: 11/13/2022] Open
Abstract
Nucleotide excision repair (NER) is a repair mechanism that removes DNA lesions induced by UV radiation, environmental mutagens, and carcinogens. There exists sufficient evidence against acetaldehyde suggesting it to cause a variety of DNA lesions and be carcinogenic to humans. Previously, we found that acetaldehyde induces reversible intra-strand GG crosslinks in DNA similar to those induced by cis-diammineplatinum(II) that is subsequently repaired by NER. In this study, we analysed the repairability by NER mechanism and the mutagenesis of acetaldehyde. In an in vitro reaction setup with NER-proficient and NER-deficient xeroderma pigmentosum group A (XPA) cell extracts, NER reactions were observed in the presence of XPA recombinant proteins in acetaldehyde-treated plasmids. Using an in vivo assay with living XPA cells and XPA-correcting XPA cells, the repair reactions were also observed. Additionally, it was observed that DNA polymerase eta inserted dATP opposite guanine in acetaldehyde-treated oligonucleotides, suggesting that acetaldehyde induced GG to TT transversions. These findings show that acetaldehyde induces NER repairable mutagenic DNA lesions.
Collapse
Affiliation(s)
- Yuina Sonohara
- Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan
| | - Reine Takatsuka
- Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan
| | - Chikahide Masutani
- Research Institute of Environmental Medicine, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
| | - Shigenori Iwai
- Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan
| | - Isao Kuraoka
- Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan.,Department of Chemistry, Faculty of Science, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan
| |
Collapse
|
38
|
Lo CY, Gao Y. DNA Helicase-Polymerase Coupling in Bacteriophage DNA Replication. Viruses 2021; 13:v13091739. [PMID: 34578319 PMCID: PMC8472574 DOI: 10.3390/v13091739] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 08/23/2021] [Accepted: 08/24/2021] [Indexed: 12/28/2022] Open
Abstract
Bacteriophages have long been model systems to study the molecular mechanisms of DNA replication. During DNA replication, a DNA helicase and a DNA polymerase cooperatively unwind the parental DNA. By surveying recent data from three bacteriophage replication systems, we summarized the mechanistic basis of DNA replication by helicases and polymerases. Kinetic data have suggested that a polymerase or a helicase alone is a passive motor that is sensitive to the base-pairing energy of the DNA. When coupled together, the helicase-polymerase complex is able to unwind DNA actively. In bacteriophage T7, helicase and polymerase reside right at the replication fork where the parental DNA is separated into two daughter strands. The two motors pull the two daughter strands to opposite directions, while the polymerase provides a separation pin to split the fork. Although independently evolved and containing different replisome components, bacteriophage T4 replisome shares mechanistic features of Hel-Pol coupling that are similar to T7. Interestingly, in bacteriophages with a limited size of genome like Φ29, DNA polymerase itself can form a tunnel-like structure, which encircles the DNA template strand and facilitates strand displacement synthesis in the absence of a helicase. Studies on bacteriophage replication provide implications for the more complicated replication systems in bacteria, archaeal, and eukaryotic systems, as well as the RNA genome replication in RNA viruses.
Collapse
Affiliation(s)
| | - Yang Gao
- Correspondence: ; Tel.: +1-713-348-2619
| |
Collapse
|
39
|
The nucleotide addition cycle of the SARS-CoV-2 polymerase. Cell Rep 2021; 36:109650. [PMID: 34433083 PMCID: PMC8367775 DOI: 10.1016/j.celrep.2021.109650] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 07/10/2021] [Accepted: 08/11/2021] [Indexed: 12/29/2022] Open
Abstract
Coronaviruses have evolved elaborate multisubunit machines to replicate and transcribe their genomes. Central to these machines are the RNA-dependent RNA polymerase subunit (nsp12) and its intimately associated cofactors (nsp7 and nsp8). We use a high-throughput magnetic-tweezers approach to develop a mechanochemical description of this core polymerase. The core polymerase exists in at least three catalytically distinct conformations, one being kinetically consistent with incorporation of incorrect nucleotides. We provide evidence that the RNA-dependent RNA polymerase (RdRp) uses a thermal ratchet instead of a power stroke to transition from the pre- to post-translocated state. Ultra-stable magnetic tweezers enable the direct observation of coronavirus polymerase deep and long-lived backtracking that is strongly stimulated by secondary structures in the template. The framework we present here elucidates one of the most important structure-dynamics-function relationships in human health today and will form the grounds for understanding the regulation of this complex.
Collapse
|
40
|
Šimoliūnienė M, Kazlauskas D, Zajančkauskaitė A, Meškys R, Truncaitė L. Escherichia coli trxAgene as a molecular marker for genome engineering of felixounoviruses. Biochim Biophys Acta Gen Subj 2021; 1865:129967. [PMID: 34324954 DOI: 10.1016/j.bbagen.2021.129967] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 07/02/2021] [Accepted: 07/24/2021] [Indexed: 11/28/2022]
Abstract
BACKGROUND Bacterial viruses (bacteriophages or phages) have a lot of uncharacterized genes, which hinders the progress of their applied research. Functional characterization of these genes is often hampered by a lack of suitable methods for engineering of phage genomes. METHODS Phages vB_EcoM_Alf5 (Alf5) and VB_EcoM_VpaE1 (VpaE1) were used as the model phages of Felixounovirus genus. The phage-coded properties were predicted by bioinformatics analysis. The 'pull-down' assay was used for detection of protein-protein interactions. Primer extension analysis was used for the DNA polymerase (DNAP) activity testing. Bacteriophage lambda Redγβα-assisted homologous recombination was used for construction of phage mutants. RESULTS Bioinformatics analysis showed that felixounoviruses encode DNA polymerase, which is homologous to the T7 DNAP. We found that the Escherichia coli thioredoxin A (TrxA) in vitro interacts with the predicted DNAP of Alf5 phage (gp096) and enhances its activity. Phages Alf5 and VpaE1 do not grow on E. coli strains lacking trxA gene unless it is provided in trans. This feature was used for construction of the deletion/insertion mutants of non-essential genes of felixounoviruses. CONCLUSION DNA replication of phages from Felixonuvirus genus depends on the host trxA, which therefore may be used as a molecular marker for their genome engineering. GENERAL SIGNIFICANCE We present a proof-of-principle of a strategy for targeted engineering of bacteriophages of Felixounovirus genus. The method developed here will facilitate the basic and applied research of this unexplored phage group. Furthermore, detected functional interactions between the phage and host proteins will be significant for basic research of DNA replication.
Collapse
Affiliation(s)
- Monika Šimoliūnienė
- Department of Molecular Microbiology and Biotechnology, Institute of Biochemistry, Life Sciences Center, Vilnius University, 7 Saulėtekio av., LT-10257 Vilnius, Lithuania.
| | - Darius Kazlauskas
- Department of Bioinformatics, Institute of Biotechnology, Life Sciences Center, Vilnius University, 7 Saulėtekio av., LT-10257 Vilnius, Lithuania.
| | - Aurelija Zajančkauskaitė
- Department of Molecular Microbiology and Biotechnology, Institute of Biochemistry, Life Sciences Center, Vilnius University, 7 Saulėtekio av., LT-10257 Vilnius, Lithuania.
| | - Rolandas Meškys
- Department of Molecular Microbiology and Biotechnology, Institute of Biochemistry, Life Sciences Center, Vilnius University, 7 Saulėtekio av., LT-10257 Vilnius, Lithuania.
| | - Lidija Truncaitė
- Department of Molecular Microbiology and Biotechnology, Institute of Biochemistry, Life Sciences Center, Vilnius University, 7 Saulėtekio av., LT-10257 Vilnius, Lithuania.
| |
Collapse
|
41
|
Structure of an open conformation of T7 DNA polymerase reveals novel structural features regulating primer-template stabilization at the polymerization active site. Biochem J 2021; 478:2665-2679. [PMID: 34160020 DOI: 10.1042/bcj20200922] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 06/21/2021] [Accepted: 06/23/2021] [Indexed: 01/25/2023]
Abstract
The crystal structure of full-length T7 DNA polymerase in complex with its processivity factor thioredoxin and double-stranded DNA in the polymerization active site exhibits two novel structural motifs in family-A DNA polymerases: an extended β-hairpin at the fingers subdomain, that interacts with the DNA template strand downstream the primer-terminus, and a helix-loop-helix motif (insertion1) located between residues 102 to 122 in the exonuclease domain. The extended β-hairpin is involved in nucleotide incorporation on substrates with 5'-overhangs longer than 2 nt, suggesting a role in stabilizing the template strand into the polymerization domain. Our biochemical data reveal that insertion1 of the exonuclease domain makes stabilizing interactions that facilitate proofreading by shuttling the primer strand into the exonuclease active site. Overall, our studies evidence conservation of the 3'-5' exonuclease domain fold between family-A DNA polymerases and highlight the modular architecture of T7 DNA polymerase. Our data suggest that the intercalating β-hairpin guides the template-strand into the polymerization active site after the T7 primase-helicase unwinds the DNA double helix ameliorating the formation of secondary structures and decreasing the appearance of indels.
Collapse
|
42
|
Cheun YK, Groehler AS, Schärer OD. New Synthetic Analogs of Nitrogen Mustard DNA Interstrand Cross-Links and Their Use to Study Lesion Bypass by DNA Polymerases. Chem Res Toxicol 2021; 34:1790-1799. [PMID: 34133118 DOI: 10.1021/acs.chemrestox.1c00123] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Nitrogen mustards are a widely used class of antitumor agents that exert their cytotoxic effects through the formation of DNA interstrand cross-links (ICLs). Despite being among the first antitumor agents used, the biological responses to NM ICLs remain only partially understood. We have previously reported the generation of NM ICL mimics by incorporation of ICL precursors into DNA using solid-phase synthesis at defined positions, followed by a double reductive amination reaction. However, the structure of these mimics deviated from the native NM ICLs. Using further development of our approach, we report a new class of NM ICL mimics that only differ from their native counterpart by substitution of dG with 7-deaza-dG at the ICL. Importantly, this approach allows for the synthesis of diverse NM ICLs, illustrated here with a mimic of the adduct formed by chlorambucil. We used the newly generated ICLs in reactions with replicative and translesion synthesis DNA polymerase to demonstrate their stability and utility for functional studies. These new NM ICLs will allow for the further characterization of the biological responses to this important class of antitumor agents.
Collapse
Affiliation(s)
- Young K Cheun
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Republic of Korea
| | - Arnold S Groehler
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Republic of Korea
| | - Orlando D Schärer
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Republic of Korea.,Department of Biological Sciences, School of Life Sciences, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| |
Collapse
|
43
|
Multiple deprotonation paths of the nucleophile 3'-OH in the DNA synthesis reaction. Proc Natl Acad Sci U S A 2021; 118:2103990118. [PMID: 34088846 DOI: 10.1073/pnas.2103990118] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
DNA synthesis by polymerases is essential for life. Deprotonation of the nucleophile 3'-OH is thought to be the obligatory first step in the DNA synthesis reaction. We have examined each entity surrounding the nucleophile 3'-OH in the reaction catalyzed by human DNA polymerase (Pol) η and delineated the deprotonation process by combining mutagenesis with steady-state kinetics, high-resolution structures of in crystallo reactions, and molecular dynamics simulations. The conserved S113 residue, which forms a hydrogen bond with the primer 3'-OH in the ground state, stabilizes the primer end in the active site. Mutation of S113 to alanine destabilizes primer binding and reduces the catalytic efficiency. Displacement of a water molecule that is hydrogen bonded to the 3'-OH using the 2'-OH of a ribonucleotide or 2'-F has little effect on catalysis. Moreover, combining the S113A mutation with 2'-F replacement, which removes two potential hydrogen acceptors of the 3'-OH, does not reduce the catalytic efficiency. We conclude that the proton can leave the O3' via alternative paths, supporting the hypothesis that binding of the third Mg2+ initiates the reaction by breaking the α-β phosphodiester bond of an incoming deoxyribonucleoside triphosphate (dNTP).
Collapse
|
44
|
Chim N, Meza RA, Trinh AM, Yang K, Chaput JC. Following replicative DNA synthesis by time-resolved X-ray crystallography. Nat Commun 2021; 12:2641. [PMID: 33976175 PMCID: PMC8113479 DOI: 10.1038/s41467-021-22937-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Accepted: 04/06/2021] [Indexed: 11/09/2022] Open
Abstract
The mechanism of DNA synthesis has been inferred from static structures, but the absence of temporal information raises longstanding questions about the order of events in one of life's most central processes. Here we follow the reaction pathway of a replicative DNA polymerase using time-resolved X-ray crystallography to elucidate the order and transition between intermediates. In contrast to the canonical model, the structural changes observed in the time-lapsed images reveal a catalytic cycle in which translocation precedes catalysis. The translocation step appears to follow a push-pull mechanism where the O-O1 loop of the finger subdomain acts as a pawl to facilitate unidirectional movement along the template with conserved tyrosine residues 714 and 719 functioning as tandem gatekeepers of DNA synthesis. The structures capture the precise order of critical events that may be a general feature of enzymatic catalysis among replicative DNA polymerases.
Collapse
Affiliation(s)
- Nicholas Chim
- Department of Pharmaceutical Sciences, University of California, Irvine, CA, USA
| | - Roman A Meza
- Department of Pharmaceutical Sciences, University of California, Irvine, CA, USA
| | - Anh M Trinh
- Department of Pharmaceutical Sciences, University of California, Irvine, CA, USA
| | - Kefan Yang
- Department of Chemical and Biomolecular Engineering, University of California, Irvine, CA, USA
| | - John C Chaput
- Department of Pharmaceutical Sciences, University of California, Irvine, CA, USA. .,Department of Chemistry, University of California, Irvine, CA, USA. .,Department of Molecular Biology and Biochemistry, University of California, Irvine, CA, USA. .,Department of Chemical and Biomolecular Engineering, University of California, Irvine, CA, USA.
| |
Collapse
|
45
|
Geronimo I, Vidossich P, Donati E, Vivo M. Computational investigations of polymerase enzymes: Structure, function, inhibition, and biotechnology. WIRES COMPUTATIONAL MOLECULAR SCIENCE 2021. [DOI: 10.1002/wcms.1534] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Inacrist Geronimo
- Laboratory of Molecular Modelling and Drug Discovery, Istituto Italiano di Tecnologia Genoa Italy
| | - Pietro Vidossich
- Laboratory of Molecular Modelling and Drug Discovery, Istituto Italiano di Tecnologia Genoa Italy
| | - Elisa Donati
- Laboratory of Molecular Modelling and Drug Discovery, Istituto Italiano di Tecnologia Genoa Italy
| | - Marco Vivo
- Laboratory of Molecular Modelling and Drug Discovery, Istituto Italiano di Tecnologia Genoa Italy
| |
Collapse
|
46
|
Ohashi S, Hashiya F, Abe H. Variety of Nucleotide Polymerase Mutants Aiming to Synthesize Modified RNA. Chembiochem 2021; 22:2398-2406. [PMID: 33822453 DOI: 10.1002/cbic.202100004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 04/01/2021] [Indexed: 01/09/2023]
Abstract
Significant efforts have been made to develop therapeutic RNA aptamers that exploit synthetic RNA to capture target molecules. However, ensuring RNA aptamers are resistant against intrinsic nucleases remains an issue and restricts their use as therapeutics. Introduction of chemical modifications to the 2' sugar moiety of RNA improves their stability effectively and can be achieved by chemical synthesis using modified phosphoramidites; however, this approach is not suitable for preparing long RNA molecules. Although recombinant nucleotide polymerases can transcribe RNA, these polymerases cannot synthesize modified RNA because they do not recognize 2' modified nucleoside triphosphates. In this review, we focus on several polymerase mutants that tolerate substrates containing modifications of the 2' sugar moiety to synthesize RNA, and the problems that must be overcome to prepare chemically modified RNA with high efficacy by in vitro transcription.
Collapse
Affiliation(s)
- Sana Ohashi
- Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8602, Japan
| | - Fumitaka Hashiya
- Research Center for Material Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8602, Japan
| | - Hiroshi Abe
- Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8602, Japan.,Research Center for Material Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8602, Japan.,CREST, Japan Science and Technology Agency, 7, Gobancho, Chiyoda-ku, Tokyo, 102-0076, Japan.,Institute for Glyco-core Research (iGCORE), Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8602, Japan
| |
Collapse
|
47
|
Bocanegra R, Ismael Plaza GA, Pulido CR, Ibarra B. DNA replication machinery: Insights from in vitro single-molecule approaches. Comput Struct Biotechnol J 2021; 19:2057-2069. [PMID: 33995902 PMCID: PMC8085672 DOI: 10.1016/j.csbj.2021.04.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 04/03/2021] [Accepted: 04/03/2021] [Indexed: 11/16/2022] Open
Abstract
The replisome is the multiprotein molecular machinery that replicates DNA. The replisome components work in precise coordination to unwind the double helix of the DNA and replicate the two strands simultaneously. The study of DNA replication using in vitro single-molecule approaches provides a novel quantitative understanding of the dynamics and mechanical principles that govern the operation of the replisome and its components. ‘Classical’ ensemble-averaging methods cannot obtain this information. Here we describe the main findings obtained with in vitro single-molecule methods on the performance of individual replisome components and reconstituted prokaryotic and eukaryotic replisomes. The emerging picture from these studies is that of stochastic, versatile and highly dynamic replisome machinery in which transient protein-protein and protein-DNA associations are responsible for robust DNA replication.
Collapse
Affiliation(s)
- Rebeca Bocanegra
- IMDEA Nanociencia, Faraday 9, Campus Cantoblanco, 28049 Madrid, Spain
| | - G A Ismael Plaza
- IMDEA Nanociencia, Faraday 9, Campus Cantoblanco, 28049 Madrid, Spain
| | - Carlos R Pulido
- IMDEA Nanociencia, Faraday 9, Campus Cantoblanco, 28049 Madrid, Spain
| | - Borja Ibarra
- IMDEA Nanociencia, Faraday 9, Campus Cantoblanco, 28049 Madrid, Spain
| |
Collapse
|
48
|
Zahn KE, Jensen RB, Wood RD, Doublié S. WITHDRAWN: Human DNA polymerase θ harbors DNA end-trimming activity critical for DNA repair. Mol Cell 2021; 81:1534-1547.e4. [PMID: 33577776 PMCID: PMC8231307 DOI: 10.1016/j.molcel.2021.01.021] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 11/24/2020] [Accepted: 01/15/2021] [Indexed: 12/12/2022]
Abstract
Cancers with hereditary defects in homologous recombination rely on DNA polymerase θ (pol θ) for repair of DNA double-strand breaks. During end joining, pol θ aligns microhomology tracts internal to 5'-resected broken ends. An unidentified nuclease trims the 3' ends before synthesis can occur. Here we report that a nuclease activity, which differs from the proofreading activity often associated with DNA polymerases, is intrinsic to the polymerase domain of pol θ. Like the DNA synthesis activity, the nuclease activity requires conserved metal-binding residues, metal ions, and dNTPs and is inhibited by ddNTPs or chain-terminated DNA. Our data indicate that pol θ repurposes metal ions in the polymerase active site for endonucleolytic cleavage and that the polymerase-active and end-trimming conformations of the enzyme are distinct. We reveal a nimble strategy of substrate processing that allows pol θ to trim or extend DNA depending on the DNA repair context.
Collapse
Affiliation(s)
- Karl E Zahn
- Department of Microbiology and Molecular Genetics, University of Vermont, 89 Beaumont Ave., Burlington, VT 05405, USA; Department of Therapeutic Radiology, Yale University, New Haven, CT 06510, USA
| | - Ryan B Jensen
- Department of Therapeutic Radiology, Yale University, New Haven, CT 06510, USA
| | - Richard D Wood
- Department of Epigenetics & Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, TX 78957, USA.
| | - Sylvie Doublié
- Department of Microbiology and Molecular Genetics, University of Vermont, 89 Beaumont Ave., Burlington, VT 05405, USA.
| |
Collapse
|
49
|
Abstract
DNA polymerase β (Pol β) is an essential mammalian enzyme involved in the repair of DNA damage during the base excision repair (BER) pathway. In hopes of faithfully restoring the coding potential to damaged DNA during BER, Pol β first uses a lyase activity to remove the 5'-deoxyribose phosphate moiety from a nicked BER intermediate, followed by a DNA synthesis activity to insert a nucleotide triphosphate into the resultant 1-nucleotide gapped DNA substrate. This DNA synthesis activity of Pol β has served as a model to characterize the molecular steps of the nucleotidyl transferase mechanism used by mammalian DNA polymerases during DNA synthesis. This is in part because Pol β has been extremely amenable to X-ray crystallography, with the first crystal structure of apoenzyme rat Pol β published in 1994 by Dr. Samuel Wilson and colleagues. Since this first structure, the Wilson lab and colleagues have published an astounding 267 structures of Pol β that represent different liganded states, conformations, variants, and reaction intermediates. While many labs have made significant contributions to our understanding of Pol β, the focus of this article is on the long history of the contributions from the Wilson lab. We have chosen to highlight select seminal Pol β structures with emphasis on the overarching contributions each structure has made to the field.
Collapse
Affiliation(s)
- Amy M Whitaker
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS, 66160, USA
| | - Bret D Freudenthal
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS, 66160, USA.
| |
Collapse
|
50
|
Cruz-González A, Muñoz-Velasco I, Cottom-Salas W, Becerra A, Campillo-Balderas JA, Hernández-Morales R, Vázquez-Salazar A, Jácome R, Lazcano A. Structural analysis of viral ExoN domains reveals polyphyletic hijacking events. PLoS One 2021; 16:e0246981. [PMID: 33730017 PMCID: PMC7968707 DOI: 10.1371/journal.pone.0246981] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 02/24/2021] [Indexed: 12/15/2022] Open
Abstract
Nidoviruses and arenaviruses are the only known RNA viruses encoding a 3’-5’ exonuclease domain (ExoN). The proofreading activity of the ExoN domain has played a key role in the growth of nidoviral genomes, while in arenaviruses this domain partakes in the suppression of the host innate immune signaling. Sequence and structural homology analyses suggest that these proteins have been hijacked from cellular hosts many times. Analysis of the available nidoviral ExoN sequences reveals a high conservation level comparable to that of the viral RNA-dependent RNA polymerases (RdRp), which are the most conserved viral proteins. Two highly preserved zinc fingers are present in all nidoviral exonucleases, while in the arenaviral protein only one zinc finger can be identified. This is in sharp contrast with the reported lack of zinc fingers in cellular ExoNs, and opens the possibility of therapeutic strategies in the struggle against COVID-19.
Collapse
Affiliation(s)
- Adrián Cruz-González
- Facultad de Ciencias, Universidad Nacional Autónoma de México, México City, México
| | - Israel Muñoz-Velasco
- Facultad de Ciencias, Universidad Nacional Autónoma de México, México City, México
| | - Wolfgang Cottom-Salas
- Facultad de Ciencias, Universidad Nacional Autónoma de México, México City, México
- Escuela Nacional Preparatoria, Plantel 8 Miguel E. Schulz, Universidad Nacional Autónoma de México, México City, México
| | - Arturo Becerra
- Facultad de Ciencias, Universidad Nacional Autónoma de México, México City, México
| | | | | | - Alberto Vázquez-Salazar
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, California, United States of America
| | - Rodrigo Jácome
- Facultad de Ciencias, Universidad Nacional Autónoma de México, México City, México
- * E-mail: (AL); (RJ)
| | - Antonio Lazcano
- Facultad de Ciencias, Universidad Nacional Autónoma de México, México City, México
- El Colegio Nacional, México City, México
- * E-mail: (AL); (RJ)
| |
Collapse
|