1
|
Chu X, Suo Z, Wang J. Investigating the Conformational Dynamics of a Y-Family DNA Polymerase during Its Folding and Binding to DNA and a Nucleotide. JACS AU 2022; 2:341-356. [PMID: 35252985 PMCID: PMC8889613 DOI: 10.1021/jacsau.1c00368] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Indexed: 06/14/2023]
Abstract
During DNA polymerization, the Y-family DNA polymerases are capable of bypassing various DNA damage, which can stall the replication fork progression. It has been well acknowledged that the structures of the Y-family DNA polymerases have been naturally evolved to undertake this vital task. However, the mechanisms of how these proteins utilize their unique structural and conformational dynamical features to perform the translesion DNA synthesis are less understood. Here, we developed structure-based models to study the precatalytic DNA polymerization process, including DNA and nucleotide binding to DPO4, a paradigmatic Y-family polymerase from Sulfolobus solfataricus. We studied the interplay between the folding and the conformational dynamics of DPO4 and found that DPO4 undergoes first unraveling (unfolding) and then folding for accomplishing the functional "open-to-closed" conformational transition. DNA binding dynamically modulates the conformational equilibrium in DPO4 during the stepwise binding through different types of interactions, leading to different conformational distributions of DPO4 at different DNA binding stages. We observed that nucleotide binding induces modulation of a few contacts surrounding the active site of the DPO4-DNA complex associated with a high free energy barrier. Our simulation results resonate with the experimental evidence that the conformational change at the active site led by nucleotide is the rate-limiting step of nucleotide incorporation. In combination with localized frustration analyses, we underlined the importance of DPO4 conformational dynamics and fluctuations in facilitating DNA and nucleotide binding. Our findings offer mechanistic insights into the processes of DPO4 conformational dynamics associated with the substrate binding and contribute to the understanding of the "structure-dynamics-function" relationship in the Y-family DNA polymerases.
Collapse
Affiliation(s)
- Xiakun Chu
- Department
of Chemistry, State University of New York
at Stony Brook, Stony
Brook, New York 11794, United States
| | - Zucai Suo
- Department
of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, Florida 32306, United States
| | - Jin Wang
- Department
of Chemistry, State University of New York
at Stony Brook, Stony
Brook, New York 11794, United States
- Department
of Physics and Astronomy, State University
of New York at Stony Brook, Stony Brook, New York 11794, United States
| |
Collapse
|
2
|
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
|
3
|
Chu X, Suo Z, Wang J. Investigating the trade-off between folding and function in a multidomain Y-family DNA polymerase. eLife 2020; 9:60434. [PMID: 33079059 PMCID: PMC7641590 DOI: 10.7554/elife.60434] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 10/16/2020] [Indexed: 01/01/2023] Open
Abstract
The way in which multidomain proteins fold has been a puzzling question for decades. Until now, the mechanisms and functions of domain interactions involved in multidomain protein folding have been obscure. Here, we develop structure-based models to investigate the folding and DNA-binding processes of the multidomain Y-family DNA polymerase IV (DPO4). We uncover shifts in the folding mechanism among ordered domain-wise folding, backtracking folding, and cooperative folding, modulated by interdomain interactions. These lead to ‘U-shaped’ DPO4 folding kinetics. We characterize the effects of interdomain flexibility on the promotion of DPO4–DNA (un)binding, which probably contributes to the ability of DPO4 to bypass DNA lesions, which is a known biological role of Y-family polymerases. We suggest that the native topology of DPO4 leads to a trade-off between fast, stable folding and tight functional DNA binding. Our approach provides an effective way to quantitatively correlate the roles of protein interactions in conformational dynamics at the multidomain level.
Collapse
Affiliation(s)
- Xiakun Chu
- Department of Chemistry, State University of New York at Stony Brook, New York, United States
| | - Zucai Suo
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, United States
| | - Jin Wang
- Department of Chemistry, State University of New York at Stony Brook, New York, United States
| |
Collapse
|
4
|
Alnajjar KS, Krylov IS, Negahbani A, Haratipour P, Kashemirov BA, Huang J, Mahmoud M, McKenna CE, Goodman MF, Sweasy JB. A pre-catalytic non-covalent step governs DNA polymerase β fidelity. Nucleic Acids Res 2020; 47:11839-11849. [PMID: 31732732 PMCID: PMC7145665 DOI: 10.1093/nar/gkz1076] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 10/23/2019] [Accepted: 11/07/2019] [Indexed: 12/27/2022] Open
Abstract
DNA polymerase β (pol β) selects the correct deoxyribonucleoside triphosphate for incorporation into the DNA polymer. Mistakes made by pol β lead to mutations, some of which occur within specific sequence contexts to generate mutation hotspots. The adenomatous polyposis coli (APC) gene is mutated within specific sequence contexts in colorectal carcinomas but the underlying mechanism is not fully understood. In previous work, we demonstrated that a somatic colon cancer variant of pol β, K289M, misincorporates deoxynucleotides at significantly increased frequencies over wild-type pol β within a mutation hotspot that is present several times within the APC gene. Kinetic studies provide evidence that the rate-determining step of pol β catalysis is phosphodiester bond formation and suggest that substrate selection is governed at this step. Remarkably, we show that, unlike WT, a pre-catalytic step in the K289M pol β kinetic pathway becomes slower than phosphodiester bond formation with the APC DNA sequence but not with a different DNA substrate. Based on our studies, we propose that pre-catalytic conformational changes are of critical importance for DNA polymerase fidelity within specific DNA sequence contexts.
Collapse
Affiliation(s)
- Khadijeh S Alnajjar
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85724, USA
| | - Ivan S Krylov
- Department of Chemistry, University of Southern California, Los Angeles, CA 90089, USA
| | - Amirsoheil Negahbani
- Department of Chemistry, University of Southern California, Los Angeles, CA 90089, USA
| | - Pouya Haratipour
- Department of Chemistry, University of Southern California, Los Angeles, CA 90089, USA
| | - Boris A Kashemirov
- Department of Chemistry, University of Southern California, Los Angeles, CA 90089, USA
| | - Ji Huang
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85724, USA
| | - Mariam Mahmoud
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85724, USA
| | - Charles E McKenna
- Department of Chemistry, University of Southern California, Los Angeles, CA 90089, USA
| | - Myron F Goodman
- Department of Chemistry, University of Southern California, Los Angeles, CA 90089, USA.,Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Joann B Sweasy
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85724, USA.,University of Arizona Cancer Center, Tucson, AZ 85724, USA
| |
Collapse
|
5
|
Berroyer A, Alvarado G, Larson ED. Response of Sulfolobus solfataricus Dpo4 polymerase in vitro to a DNA G-quadruplex. Mutagenesis 2020; 34:289-297. [PMID: 31169295 DOI: 10.1093/mutage/gez010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Accepted: 05/06/2019] [Indexed: 12/12/2022] Open
Abstract
Repetitive DNA sequences support the formation of structures that can interrupt replication and repair, leading to breaks and mutagenesis. One particularly stable structure is G-quadruplex (G4) DNA, which is four-stranded and formed from tandemly repetitive guanine bases. When folded within a template, G4 interferes with DNA synthesis. Similar to non-duplex structures, DNA base lesions can also halt an advancing replication fork, but the Y-family polymerases solve this problem by bypassing the damage. In order to better understand how guanine-rich DNA is replicated, we have investigated the activity of the model Y-family polymerase, Sulfolobus solfataricus P2 DNA polymerase IV (Dpo4), on guanine-rich templates in vitro. We find that Dpo4 progression on templates containing either a single GC-rich hairpin or a G4 DNA structure is greatly reduced and synthesis stalls at the structure. Human polymerase eta (hPol eta) showed the same pattern of stalling at G4; however, and in contrast to Klenow, hPol eta and Dpo4 partially synthesise into the guanine repeat. Substitution of the nucleotide selectivity residue in Dpo4 with alanine permitted ribonucleotide incorporation on unstructured templates, but this further reduced the ability of Dpo4 to synthesise across from the guanine repeats. The advancement of Dpo4 on G4 templates was highest when the reaction was supplied with only deoxycytidine triphosphate, suggesting that high-fidelity synthesis is favoured over misincorporation. Our results are consistent with a model where the Y-family polymerases pause upon encountering G4 structures but have an ability to negotiate some synthesis through tetrad-associated guanines. This suggests that the Y-family polymerases reduce mutagenesis by catalysing the accurate replication of repetitive DNA sequences, but most likely in concert with additional replication and structure resolution activities.
Collapse
Affiliation(s)
- Alexandra Berroyer
- School of Biological Sciences, Illinois State University, Normal, IL, USA
| | - Gloria Alvarado
- School of Biological Sciences, Illinois State University, Normal, IL, USA
| | - Erik D Larson
- School of Biological Sciences, Illinois State University, Normal, IL, USA
| |
Collapse
|
6
|
Liptak C, Mahmoud MM, Eckenroth BE, Moreno MV, East K, Alnajjar KS, Huang J, Towle-Weicksel JB, Doublié S, Loria J, Sweasy JB. I260Q DNA polymerase β highlights precatalytic conformational rearrangements critical for fidelity. Nucleic Acids Res 2019; 46:10740-10756. [PMID: 30239932 PMCID: PMC6237750 DOI: 10.1093/nar/gky825] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 09/05/2018] [Indexed: 11/14/2022] Open
Abstract
DNA polymerase β (pol β) fills single nucleotide gaps in DNA during base excision repair and non-homologous end-joining. Pol β must select the correct nucleotide from among a pool of four nucleotides with similar structures and properties in order to maintain genomic stability during DNA repair. Here, we use a combination of X-ray crystallography, fluorescence resonance energy transfer and nuclear magnetic resonance to show that pol β‘s ability to access the appropriate conformations both before and upon binding to nucleotide substrates is integral to its fidelity. Importantly, we also demonstrate that the inability of the I260Q mutator variant of pol β to properly navigate this conformational landscape results in error-prone DNA synthesis. Our work reveals that precatalytic conformational rearrangements themselves are an important underlying mechanism of substrate selection by DNA pol β.
Collapse
Affiliation(s)
- Cary Liptak
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | - Mariam M Mahmoud
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Brian E Eckenroth
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, VT 05405, USA
| | - Marcus V Moreno
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, VT 05405, USA
| | - Kyle East
- Department of Chemistry, Yale University, New Haven, CT 06520, USA
| | - Khadijeh S Alnajjar
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Ji Huang
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Jamie B Towle-Weicksel
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Sylvie Doublié
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, VT 05405, USA
| | - J Patrick Loria
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
- Department of Chemistry, Yale University, New Haven, CT 06520, USA
- To whom correspondence should be addressed. Tel: +203 436 2518; Fax: +203 436 6144; . Correspondence may also be addressed to Joann B. Sweasy. Tel: +203 737 2626; Fax: +203 785 6309;
| | - Joann B Sweasy
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT 06520, USA
- Department of Genetics, Yale University School of Medicine, New Haven, CT 06520, USA
- To whom correspondence should be addressed. Tel: +203 436 2518; Fax: +203 436 6144; . Correspondence may also be addressed to Joann B. Sweasy. Tel: +203 737 2626; Fax: +203 785 6309;
| |
Collapse
|
7
|
Affiliation(s)
- Vito Genna
- Laboratory of Molecular Modeling and Drug Discovery, Istituto Italiano di Tecnologia, Via Morego 30, 16163, Genoa, Italy
| | - Elisa Donati
- Laboratory of Molecular Modeling and Drug Discovery, Istituto Italiano di Tecnologia, Via Morego 30, 16163, Genoa, Italy
| | - Marco De Vivo
- Laboratory of Molecular Modeling and Drug Discovery, Istituto Italiano di Tecnologia, Via Morego 30, 16163, Genoa, Italy
| |
Collapse
|
8
|
Raper AT, Reed AJ, Suo Z. Kinetic Mechanism of DNA Polymerases: Contributions of Conformational Dynamics and a Third Divalent Metal Ion. Chem Rev 2018; 118:6000-6025. [DOI: 10.1021/acs.chemrev.7b00685] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Austin T. Raper
- Department of Chemistry and Biochemistry, Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio 43210, United States
| | - Andrew J. Reed
- Department of Chemistry and Biochemistry, Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio 43210, United States
| | - Zucai Suo
- Department of Chemistry and Biochemistry, Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio 43210, United States
| |
Collapse
|
9
|
Lee E, Fowler JD, Suo Z, Wu Z. Backbone assignment of the binary complex of the full length Sulfolobus solfataricus DNA polymerase IV and DNA. BIOMOLECULAR NMR ASSIGNMENTS 2017; 11:39-43. [PMID: 27738883 DOI: 10.1007/s12104-016-9717-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Accepted: 10/08/2016] [Indexed: 05/03/2023]
Abstract
Sulfolobus solfataricus DNA polymerase IV (Dpo4), a model Y-family DNA polymerase, bypasses a wide range of DNA lesions in vitro and in vivo. In this paper, we report the backbone chemical shift assignments of the full length Dpo4 in its binary complex with a 14/14-mer DNA substrate. Upon DNA binding, several β-stranded regions in the isolated catalytic core and little finger/linker fragments of Dpo4 become more structured. This work serves as a foundation for our ongoing investigation of conformational dynamics of Dpo4 and future determination of the first solution structures of a DNA polymerase and its binary and ternary complexes.
Collapse
Affiliation(s)
- Eunjeong Lee
- Department of Chemistry and Biochemistry, The Ohio State University, 876 Biological Sciences, 484 West 12th Ave., Columbus, OH, 43210, USA
| | - Jason D Fowler
- Department of Chemistry and Biochemistry, The Ohio State University, 876 Biological Sciences, 484 West 12th Ave., Columbus, OH, 43210, USA
| | - Zucai Suo
- Department of Chemistry and Biochemistry, The Ohio State University, 876 Biological Sciences, 484 West 12th Ave., Columbus, OH, 43210, USA
| | - Zhengrong Wu
- Department of Chemistry and Biochemistry, The Ohio State University, 876 Biological Sciences, 484 West 12th Ave., Columbus, OH, 43210, USA.
| |
Collapse
|
10
|
Raper AT, Reed AJ, Gadkari VV, Suo Z. Advances in Structural and Single-Molecule Methods for Investigating DNA Lesion Bypass and Repair Polymerases. Chem Res Toxicol 2016; 30:260-269. [PMID: 28092942 DOI: 10.1021/acs.chemrestox.6b00342] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Innovative advances in X-ray crystallography and single-molecule biophysics have yielded unprecedented insight into the mechanisms of DNA lesion bypass and damage repair. Time-dependent X-ray crystallography has been successfully applied to view the bypass of 8-oxo-7,8-dihydro-2'-deoxyguanine (8-oxoG), a major oxidative DNA lesion, and the incorporation of the triphosphate form, 8-oxo-dGTP, catalyzed by human DNA polymerase β. Significant findings of these studies are highlighted here, and their contributions to the current mechanistic understanding of mutagenic translesion DNA synthesis (TLS) and base excision repair are discussed. In addition, single-molecule Förster resonance energy transfer (smFRET) techniques have recently been adapted to investigate nucleotide binding and incorporation opposite undamaged dG and 8-oxoG by Sulfolobus solfataricus DNA polymerase IV (Dpo4), a model Y-family DNA polymerase. The mechanistic response of Dpo4 to a DNA lesion and the complex smFRET technique are described here. In this perspective, we also describe how time-dependent X-ray crystallography and smFRET can be used to achieve the spatial and temporal resolutions necessary to answer some of the mechanistic questions that remain in the fields of TLS and DNA damage repair.
Collapse
Affiliation(s)
- Austin T Raper
- Department of Chemistry and Biochemistry and The Ohio State Biochemistry Program, The Ohio State University , Columbus, Ohio 43210, United States
| | - Andrew J Reed
- Department of Chemistry and Biochemistry and The Ohio State Biochemistry Program, The Ohio State University , Columbus, Ohio 43210, United States
| | - Varun V Gadkari
- Department of Chemistry and Biochemistry and The Ohio State Biochemistry Program, The Ohio State University , Columbus, Ohio 43210, United States
| | - Zucai Suo
- Department of Chemistry and Biochemistry and The Ohio State Biochemistry Program, The Ohio State University , Columbus, Ohio 43210, United States
| |
Collapse
|
11
|
Raper AT, Suo Z. Investigation of Intradomain Motions of a Y-Family DNA Polymerase during Substrate Binding and Catalysis. Biochemistry 2016; 55:5832-5844. [PMID: 27685341 DOI: 10.1021/acs.biochem.6b00878] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
DNA polymerases catalyze DNA synthesis through a stepwise kinetic mechanism that begins with binding to DNA, followed by selection, binding, and incorporation of a nucleotide into an elongating primer. It is hypothesized that subtle active site adjustments in a polymerase to align reactive moieties limit the rate of correct nucleotide incorporation. DNA damage can impede this process for many DNA polymerases, causing replication fork stalling, genetic mutations, and potentially cell death. However, specialized Y-family DNA polymerases are structurally evolved to efficiently bypass DNA damage in vivo, albeit at the expense of replication fidelity. Dpo4, a model Y-family polymerase from Sulfolobus solfataricus, has been well-studied kinetically, structurally, and computationally, which yielded a mechanistic understanding of how the Y-family DNA polymerases achieve their unique catalytic properties. We previously employed a real-time Förster resonance energy transfer (FRET) technique to characterize the global conformational motions of Dpo4 during DNA binding as well as nucleotide binding and incorporation by monitoring changes in distance between sites on the polymerase and DNA, and even between domains of Dpo4. Here, we extend the utility of our FRET methodology to observe conformational transitions within individual domains of Dpo4 during DNA binding and nucleotide incorporation. The results of this novel, intradomain FRET approach unify findings from many studies to fully clarify the complex DNA binding mechanism of Dpo4. Furthermore, intradomain motions in the Finger domain during nucleotide binding and incorporation, for the first time, report on the rate-limiting step of a single-nucleotide addition catalyzed by Dpo4.
Collapse
Affiliation(s)
- Austin T Raper
- Department of Chemistry and Biochemistry, The Ohio State University , Columbus, Ohio 43210, United States.,Ohio State Biochemistry Program, The Ohio State University , Columbus, Ohio 43210, United States
| | - Zucai Suo
- Department of Chemistry and Biochemistry, The Ohio State University , Columbus, Ohio 43210, United States.,Ohio State Biochemistry Program, The Ohio State University , Columbus, Ohio 43210, United States
| |
Collapse
|
12
|
Albrecht L, Wilson KA, Wetmore SD. Computational Evaluation of Nucleotide Insertion Opposite Expanded and Widened DNA by the Translesion Synthesis Polymerase Dpo4. Molecules 2016; 21:molecules21070822. [PMID: 27347908 PMCID: PMC6273265 DOI: 10.3390/molecules21070822] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 06/08/2016] [Accepted: 06/14/2016] [Indexed: 11/25/2022] Open
Abstract
Expanded (x) and widened (y) deoxyribose nucleic acids (DNA) have an extra benzene ring incorporated either horizontally (xDNA) or vertically (yDNA) between a natural pyrimidine base and the deoxyribose, or between the 5- and 6-membered rings of a natural purine. Far-reaching applications for (x,y)DNA include nucleic acid probes and extending the natural genetic code. Since modified nucleobases must encode information that can be passed to the next generation in order to be a useful extension of the genetic code, the ability of translesion (bypass) polymerases to replicate modified bases is an active area of research. The common model bypass polymerase DNA polymerase IV (Dpo4) has been previously shown to successfully replicate and extend past a single modified nucleobase on a template DNA strand. In the current study, molecular dynamics (MD) simulations are used to evaluate the accommodation of expanded/widened nucleobases in the Dpo4 active site, providing the first structural information on the replication of (x,y)DNA. Our results indicate that the Dpo4 catalytic (palm) domain is not significantly impacted by the (x,y)DNA bases. Instead, the template strand is displaced to accommodate the increased C1’–C1’ base-pair distance. The structural insights unveiled in the present work not only increase our fundamental understanding of Dpo4 replication, but also reveal the process by which Dpo4 replicates (x,y)DNA, and thereby will contribute to the optimization of high fidelity and efficient polymerases for the replication of modified nucleobases.
Collapse
Affiliation(s)
- Laura Albrecht
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge Alberta, AB T1K 3M4, Canada.
| | - Katie A Wilson
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge Alberta, AB T1K 3M4, Canada.
| | - Stacey D Wetmore
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge Alberta, AB T1K 3M4, Canada.
| |
Collapse
|
13
|
Wei G, Xi W, Nussinov R, Ma B. Protein Ensembles: How Does Nature Harness Thermodynamic Fluctuations for Life? The Diverse Functional Roles of Conformational Ensembles in the Cell. Chem Rev 2016; 116:6516-51. [PMID: 26807783 PMCID: PMC6407618 DOI: 10.1021/acs.chemrev.5b00562] [Citation(s) in RCA: 253] [Impact Index Per Article: 31.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
All soluble proteins populate conformational ensembles that together constitute the native state. Their fluctuations in water are intrinsic thermodynamic phenomena, and the distributions of the states on the energy landscape are determined by statistical thermodynamics; however, they are optimized to perform their biological functions. In this review we briefly describe advances in free energy landscape studies of protein conformational ensembles. Experimental (nuclear magnetic resonance, small-angle X-ray scattering, single-molecule spectroscopy, and cryo-electron microscopy) and computational (replica-exchange molecular dynamics, metadynamics, and Markov state models) approaches have made great progress in recent years. These address the challenging characterization of the highly flexible and heterogeneous protein ensembles. We focus on structural aspects of protein conformational distributions, from collective motions of single- and multi-domain proteins, intrinsically disordered proteins, to multiprotein complexes. Importantly, we highlight recent studies that illustrate functional adjustment of protein conformational ensembles in the crowded cellular environment. We center on the role of the ensemble in recognition of small- and macro-molecules (protein and RNA/DNA) and emphasize emerging concepts of protein dynamics in enzyme catalysis. Overall, protein ensembles link fundamental physicochemical principles and protein behavior and the cellular network and its regulation.
Collapse
Affiliation(s)
- Guanghong Wei
- State Key Laboratory of Surface Physics, Key Laboratory for Computational Physical Sciences (MOE), and Department of Physics, Fudan University, Shanghai, P. R. China
| | - Wenhui Xi
- State Key Laboratory of Surface Physics, Key Laboratory for Computational Physical Sciences (MOE), and Department of Physics, Fudan University, Shanghai, P. R. China
| | - Ruth Nussinov
- Basic Science Program, Leidos Biomedical Research, Inc. Cancer and Inflammation Program, National Cancer Institute, Frederick, Maryland 21702, USA
- Sackler Inst. of Molecular Medicine Department of Human Genetics and Molecular Medicine Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Buyong Ma
- Basic Science Program, Leidos Biomedical Research, Inc. Cancer and Inflammation Program, National Cancer Institute, Frederick, Maryland 21702, USA
| |
Collapse
|
14
|
Raper AT, Gadkari VV, Maxwell BA, Suo Z. Single-Molecule Investigation of Response to Oxidative DNA Damage by a Y-Family DNA Polymerase. Biochemistry 2016; 55:2187-96. [PMID: 27002236 DOI: 10.1021/acs.biochem.6b00166] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Y-family DNA polymerases are known to bypass DNA lesions in vitro and in vivo and rescue stalled DNA replication machinery. Dpo4, a well-characterized model Y-family DNA polymerase, is known to catalyze translesion synthesis across a variety of DNA lesions including 8-oxo-7,8-dihydro-2'-deoxyguanine (8-oxo-dG). Our previous X-ray crystallographic, stopped-flow Förster resonance energy transfer (FRET), and computational simulation studies have revealed that Dpo4 samples a variety of global conformations as it recognizes and binds DNA. Here we employed single-molecule FRET (smFRET) techniques to investigate the kinetics and conformational dynamics of Dpo4 when it encountered 8-oxo-dG, a major oxidative lesion with high mutagenic potential. Our smFRET data indicated that Dpo4 bound the DNA substrate in multiple conformations, as suggested by three observed FRET states. An incoming correct or incorrect nucleotide affected the distribution and stability of these states with the correct nucleotide completely shifting the equilibrium toward a catalytically competent complex. Furthermore, the presence of the 8-oxo-dG lesion in the DNA stabilized both the binary and ternary complexes of Dpo4. Thus, our smFRET analysis provided a basis for the enhanced efficiency which Dpo4 is known to exhibit when replicating across from 8-oxo-dG.
Collapse
Affiliation(s)
- Austin T Raper
- Department of Chemistry and Biochemistry, †Ohio State Biochemistry Program and ‡Ohio State Biophysics Program, The Ohio State University , Columbus, Ohio 43210, United States
| | - Varun V Gadkari
- Department of Chemistry and Biochemistry, †Ohio State Biochemistry Program and ‡Ohio State Biophysics Program, The Ohio State University , Columbus, Ohio 43210, United States
| | - Brian A Maxwell
- Department of Chemistry and Biochemistry, †Ohio State Biochemistry Program and ‡Ohio State Biophysics Program, The Ohio State University , Columbus, Ohio 43210, United States
| | - Zucai Suo
- Department of Chemistry and Biochemistry, †Ohio State Biochemistry Program and ‡Ohio State Biophysics Program, The Ohio State University , Columbus, Ohio 43210, United States
| |
Collapse
|
15
|
Archaeal DNA polymerases in biotechnology. Appl Microbiol Biotechnol 2015; 99:6585-97. [DOI: 10.1007/s00253-015-6781-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Revised: 06/12/2015] [Accepted: 06/17/2015] [Indexed: 10/23/2022]
|
16
|
Nevin P, Lu X, Zhang K, Engen JR, Beuning PJ. Noncognate DNA damage prevents the formation of the active conformation of the Y-family DNA polymerases DinB and DNA polymerase κ. FEBS J 2015; 282:2646-60. [PMID: 25899385 DOI: 10.1111/febs.13304] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Revised: 04/17/2015] [Accepted: 04/20/2015] [Indexed: 01/24/2023]
Abstract
Y-family DNA polymerases are specialized to copy damaged DNA, and are associated with increased mutagenesis, owing to their low fidelity. It is believed that the mechanism of nucleotide selection by Y-family DNA polymerases involves conformational changes preceding nucleotidyl transfer, but there is limited experimental evidence for such structural changes. In particular, nucleotide-induced conformational changes in bacterial or eukaryotic Y-family DNA polymerases have, to date, not been extensively characterized. Using hydrogen-deuterium exchange mass spectrometry, we demonstrate here that the Escherichia coli Y-family DNA polymerase DinB and its human ortholog DNA polymerase κ undergo a conserved nucleotide-induced conformational change in the presence of undamaged DNA and the correct incoming nucleotide. Notably, this holds true for damaged DNA containing N(2) -furfuryl-deoxyguanosine, which is efficiently copied by these two polymerases, but not for damaged DNA containing the major groove modification O(6) -methyl-deoxyguanosine, which is a poor substrate. Our observations suggest that DinB and DNA polymerase κ utilize a common mechanism for nucleotide selection involving a conserved prechemical conformational transition promoted by the correct nucleotide and only preferred DNA substrates.
Collapse
Affiliation(s)
- Philip Nevin
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, USA
| | - Xueguang Lu
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, USA
| | - Ke Zhang
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, USA
| | - John R Engen
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, USA
| | - Penny J Beuning
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, USA
| |
Collapse
|
17
|
Vyas R, Reed AJ, Tokarsky EJ, Suo Z. Viewing Human DNA Polymerase β Faithfully and Unfaithfully Bypass an Oxidative Lesion by Time-Dependent Crystallography. J Am Chem Soc 2015; 137:5225-30. [PMID: 25825995 DOI: 10.1021/jacs.5b02109] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
One common oxidative DNA lesion, 8-oxo-7,8-dihydro-2'-deoxyguanine (8-oxoG), is highly mutagenic in vivo due to its anti-conformation forming a Watson-Crick base pair with correct deoxycytidine 5'-triphosphate (dCTP) and its syn-conformation forming a Hoogsteen base pair with incorrect deoxyadenosine 5'-triphosphate (dATP). Here, we utilized time-resolved X-ray crystallography to follow 8-oxoG bypass by human DNA polymerase β (hPolβ). In the 12 solved structures, both Watson-Crick (anti-8-oxoG:anti-dCTP) and Hoogsteen (syn-8-oxoG:anti-dATP) base pairing were clearly visible and were maintained throughout the chemical reaction. Additionally, a third Mg(2+) appeared during the process of phosphodiester bond formation and was located between the reacting α- and β-phosphates of the dNTP, suggesting its role in stabilizing reaction intermediates. After phosphodiester bond formation, hPolβ reopened its conformation, pyrophosphate was released, and the newly incorporated primer 3'-terminal nucleotide stacked, rather than base paired, with 8-oxoG. These structures provide the first real-time pictures, to our knowledge, of how a polymerase correctly and incorrectly bypasses a DNA lesion.
Collapse
Affiliation(s)
- Rajan Vyas
- †Department of Chemistry and Biochemistry, ‡The Ohio State Biochemistry and §Biophysics Programs, The Ohio State University, Columbus, Ohio 43210, United States
| | - Andrew J Reed
- †Department of Chemistry and Biochemistry, ‡The Ohio State Biochemistry and §Biophysics Programs, The Ohio State University, Columbus, Ohio 43210, United States
| | - E John Tokarsky
- †Department of Chemistry and Biochemistry, ‡The Ohio State Biochemistry and §Biophysics Programs, The Ohio State University, Columbus, Ohio 43210, United States
| | - Zucai Suo
- †Department of Chemistry and Biochemistry, ‡The Ohio State Biochemistry and §Biophysics Programs, The Ohio State University, Columbus, Ohio 43210, United States
| |
Collapse
|
18
|
Zhao L, Pence MG, Eoff RL, Yuan S, Fercu CA, Guengerich FP. Elucidation of kinetic mechanisms of human translesion DNA polymerase κ using tryptophan mutants. FEBS J 2014; 281:4394-410. [PMID: 25065501 PMCID: PMC4182141 DOI: 10.1111/febs.12947] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Revised: 07/18/2014] [Accepted: 07/23/2014] [Indexed: 02/05/2023]
Abstract
To investigate the conformational dynamics of human DNA polymerase κ (hpol κ), we generated two mutants, Y50W (N-clasp region) and Y408W (linker between the thumb and little finger domains), using a Trp-null mutant (W214Y/W392H) of the hpol κ catalytic core enzyme. These mutants retained catalytic activity and similar patterns of selectivity for bypassing the DNA adduct 7,8-dihydro-8-oxo-2'-deoxyguanosine, as indicated by the results of steady-state and pre-steady-state kinetic experiments. Stopped-flow kinetic assays with hpol κ Y50W and T408W revealed a decrease in Trp fluorescence with the template G:dCTP pair but not for any mispairs. This decrease in fluorescence was not rate-limiting and is considered to be related to a conformational change necessary for correct nucleotidyl transfer. When a free 3'-hydroxyl was present on the primer, the Trp fluorescence returned to the baseline level at a rate similar to the observed kcat , suggesting that this change occurs during or after nucleotidyl transfer. However, polymerization rates (kpol ) of extended-product formation were fast, indicating that the slow fluorescence step follows phosphodiester bond formation and is rate-limiting. Pyrophosphate formation and release were fast and are likely to precede the slower relaxation step. The available kinetic data were used to fit a simplified minimal model. The extracted rate constants confirmed that the conformational change after phosphodiester bond formation was rate-limiting for hpol κ catalysis with the template G:dCTP pair.
Collapse
Affiliation(s)
- Linlin Zhao
- Department of Biochemistry and Center in Molecular Toxicology, Vanderbilt University School of Medicine, Nashville, TN, 37232 USA
- Department of Chemistry and Biochemistry, Central Michigan University, Mount Pleasant, MI 48859 USA
| | - Matthew G. Pence
- Department of Biochemistry and Center in Molecular Toxicology, Vanderbilt University School of Medicine, Nashville, TN, 37232 USA
| | - Robert L. Eoff
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR, 72205 USA
| | - Shuai Yuan
- Department of Biochemistry and Center in Molecular Toxicology, Vanderbilt University School of Medicine, Nashville, TN, 37232 USA
| | - Catinca A. Fercu
- Department of Biochemistry and Center in Molecular Toxicology, Vanderbilt University School of Medicine, Nashville, TN, 37232 USA
| | - F. Peter Guengerich
- Department of Biochemistry and Center in Molecular Toxicology, Vanderbilt University School of Medicine, Nashville, TN, 37232 USA
| |
Collapse
|
19
|
Dynamic conformational change regulates the protein-DNA recognition: an investigation on binding of a Y-family polymerase to its target DNA. PLoS Comput Biol 2014; 10:e1003804. [PMID: 25188490 PMCID: PMC4154647 DOI: 10.1371/journal.pcbi.1003804] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Accepted: 07/10/2014] [Indexed: 12/02/2022] Open
Abstract
Protein-DNA recognition is a central biological process that governs the life of cells. A protein will often undergo a conformational transition to form the functional complex with its target DNA. The protein conformational dynamics are expected to contribute to the stability and specificity of DNA recognition and therefore may control the functional activity of the protein-DNA complex. Understanding how the conformational dynamics influences the protein-DNA recognition is still challenging. Here, we developed a two-basin structure-based model to explore functional dynamics in Sulfolobus solfataricus DNA Y-family polymerase IV (DPO4) during its binding to DNA. With explicit consideration of non-specific and specific interactions between DPO4 and DNA, we found that DPO4-DNA recognition is comprised of first 3D diffusion, then a short-range adjustment sliding on DNA and finally specific binding. Interestingly, we found that DPO4 is under a conformational equilibrium between multiple states during the binding process and the distributions of the conformations vary at different binding stages. By modulating the strength of the electrostatic interactions, the flexibility of the linker, and the conformational dynamics in DPO4, we drew a clear picture on how DPO4 dynamically regulates the DNA recognition. We argue that the unique features of flexibility and conformational dynamics in DPO4-DNA recognition have direct implications for low-fidelity translesion DNA synthesis, most of which is found to be accomplished by the Y-family DNA polymerases. Our results help complete the description of the DNA synthesis process for the Y-family polymerases. Furthermore, the methods developed here can be widely applied for future investigations on how various proteins recognize and bind specific DNA substrates. Protein-DNA recognition is crucial for many key biological processes in cells. Protein often undergoes large-scale conformational change during DNA recognition. However, the physical and global understanding of flexible protein-DNA binding is still challenging. Here, we developed a theoretical approach to investigate binding of a Y-family DNA polymerase to its target DNA during the DNA synthesis process. The results of electrostatic-controlled multi-step DNA binding process accompanied with multi-state conformational transition of protein occurring throughout are in remarkable agreement with experiments. During the process of protein-DNA recognition, the flexibility is found to facilitate both the conformational transition of protein (intra-chain dynamics) and DNA binding (inter-chain dynamics) simultaneously. Therefore, we provided a quantitative description of protein-DNA binding mechanism that flexibility or conformational change regulates DNA recognition dynamically, leading to high efficiency and specificity of function for protein-DNA recognition.
Collapse
|
20
|
Gaur V, Vyas R, Fowler JD, Efthimiopoulos G, Feng JY, Suo Z. Structural and kinetic insights into binding and incorporation of L-nucleotide analogs by a Y-family DNA polymerase. Nucleic Acids Res 2014; 42:9984-95. [PMID: 25104018 PMCID: PMC4150803 DOI: 10.1093/nar/gku709] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Considering that all natural nucleotides (D-dNTPs) and the building blocks (D-dNMPs) of DNA chains possess D-stereochemistry, DNA polymerases and reverse transcriptases (RTs) likely possess strongD-stereoselectivity by preferably binding and incorporating D-dNTPs over unnatural L-dNTPs during DNA synthesis. Surprisingly, a structural basis for the discrimination against L-dNTPs by DNA polymerases or RTs has not been established although L-deoxycytidine analogs (lamivudine and emtricitabine) and L-thymidine (telbivudine) have been widely used as antiviral drugs for years. Here we report seven high-resolution ternary crystal structures of a prototype Y-family DNA polymerase, DNA, and D-dCTP, D-dCDP, L-dCDP, or the diphosphates and triphosphates of lamivudine and emtricitabine. These structures reveal that relative to D-dCTP, each of these L-nucleotides has its sugar ring rotated by 180° with an unusual O4'-endo sugar puckering and exhibits multiple triphosphate-binding conformations within the active site of the polymerase. Such rare binding modes significantly decrease the incorporation rates and efficiencies of these L-nucleotides catalyzed by the polymerase.
Collapse
Affiliation(s)
- Vineet Gaur
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
| | - Rajan Vyas
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
| | - Jason D Fowler
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
| | - Georgia Efthimiopoulos
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
| | - Joy Y Feng
- Gilead Sciences, Inc., 333 Lakeside Drive, Foster City, CA 94044, USA
| | - Zucai Suo
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
| |
Collapse
|
21
|
Xu C, Maxwell BA, Suo Z. Conformational dynamics of Thermus aquaticus DNA polymerase I during catalysis. J Mol Biol 2014; 426:2901-2917. [PMID: 24931550 DOI: 10.1016/j.jmb.2014.06.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Revised: 06/02/2014] [Accepted: 06/07/2014] [Indexed: 11/15/2022]
Abstract
Despite the fact that DNA polymerases have been investigated for many years and are commonly used as tools in a number of molecular biology assays, many details of the kinetic mechanism they use to catalyze DNA synthesis remain unclear. Structural and kinetic studies have characterized a rapid, pre-catalytic open-to-close conformational change of the Finger domain during nucleotide binding for many DNA polymerases including Thermus aquaticus DNA polymerase I (Taq Pol), a thermostable enzyme commonly used for DNA amplification in PCR. However, little has been performed to characterize the motions of other structural domains of Taq Pol or any other DNA polymerase during catalysis. Here, we used stopped-flow Förster resonance energy transfer to investigate the conformational dynamics of all five structural domains of the full-length Taq Pol relative to the DNA substrate during nucleotide binding and incorporation. Our study provides evidence for a rapid conformational change step induced by dNTP binding and a subsequent global conformational transition involving all domains of Taq Pol during catalysis. Additionally, our study shows that the rate of the global transition was greatly increased with the truncated form of Taq Pol lacking the N-terminal domain. Finally, we utilized a mutant of Taq Pol containing a de novo disulfide bond to demonstrate that limiting protein conformational flexibility greatly reduced the polymerization activity of Taq Pol.
Collapse
Affiliation(s)
- Cuiling Xu
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
| | - Brian A Maxwell
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA.,Ohio State Biophysics Program, The Ohio State University, Columbus, OH 43210, USA
| | - Zucai Suo
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA.,Ohio State Biophysics Program, The Ohio State University, Columbus, OH 43210, USA
| |
Collapse
|
22
|
Towle-Weicksel JB, Dalal S, Sohl CD, Doublié S, Anderson KS, Sweasy JB. Fluorescence resonance energy transfer studies of DNA polymerase β: the critical role of fingers domain movements and a novel non-covalent step during nucleotide selection. J Biol Chem 2014; 289:16541-50. [PMID: 24764311 DOI: 10.1074/jbc.m114.561878] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
During DNA repair, DNA polymerase β (Pol β) is a highly dynamic enzyme that is able to select the correct nucleotide opposite a templating base from a pool of four different deoxynucleoside triphosphates (dNTPs). To gain insight into nucleotide selection, we use a fluorescence resonance energy transfer (FRET)-based system to monitor movement of the Pol β fingers domain during catalysis in the presence of either correct or incorrect dNTPs. By labeling the fingers domain with ((((2-iodoacetyl)amino)ethyl)amino)naphthalene-1-sulfonic acid (IAEDANS) and the DNA substrate with Dabcyl, we are able to observe rapid fingers closing in the presence of correct dNTPs as the IAEDANS comes into contact with a Dabcyl-labeled, one-base gapped DNA. Our findings show that not only do the fingers close after binding to the correct dNTP, but that there is a second conformational change associated with a non-covalent step not previously reported for Pol β. Further analyses suggest that this conformational change corresponds to the binding of the catalytic metal into the polymerase active site. FRET studies with incorrect dNTP result in no changes in fluorescence, indicating that the fingers do not close in the presence of incorrect dNTP. Together, our results show that nucleotide selection initially occurs in an open fingers conformation and that the catalytic pathways of correct and incorrect dNTPs differ from each other. Overall, this study provides new insight into the mechanism of substrate choice by a polymerase that plays a critical role in maintaining genome stability.
Collapse
Affiliation(s)
| | | | - Christal D Sohl
- Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06520 and
| | - Sylvie Doublié
- the Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, Vermont 05405
| | - Karen S Anderson
- Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06520 and
| | | |
Collapse
|
23
|
Maxwell BA, Suo Z. Recent insight into the kinetic mechanisms and conformational dynamics of Y-Family DNA polymerases. Biochemistry 2014; 53:2804-14. [PMID: 24716482 PMCID: PMC4018064 DOI: 10.1021/bi5000405] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
![]()
The
kinetic mechanisms by which DNA polymerases catalyze DNA replication
and repair have long been areas of active research. Recently discovered
Y-family DNA polymerases catalyze the bypass of damaged DNA bases
that would otherwise block replicative DNA polymerases and stall replication
forks. Unlike DNA polymerases from the five other families, the Y-family
DNA polymerases have flexible, solvent-accessible active sites that
are able to tolerate various types of damaged template bases and allow
for efficient lesion bypass. Their promiscuous active sites, however,
also lead to fidelities that are much lower than those observed for
other DNA polymerases and give rise to interesting mechanistic properties.
Additionally, the Y-family DNA polymerases have several other unique
structural features and undergo a set of conformational changes during
substrate binding and catalysis different from those observed for
replicative DNA polymerases. In recent years, pre-steady-state kinetic
methods have been extensively employed to reveal a wealth of information
about the catalytic properties of these fascinating noncanonical DNA
polymerases. Here, we review many of the recent findings on the kinetic
mechanisms of DNA polymerization with undamaged and damaged DNA substrates
by the Y-family DNA polymerases, and the conformational dynamics employed
by these error-prone enzymes during catalysis.
Collapse
Affiliation(s)
- Brian A Maxwell
- Ohio State Biophysics Program and ‡Department of Chemistry and Biochemistry, The Ohio State University , Columbus, Ohio 43210, United States
| | | |
Collapse
|
24
|
Maxwell BA, Xu C, Suo Z. Conformational dynamics of a Y-family DNA polymerase during substrate binding and catalysis as revealed by interdomain Förster resonance energy transfer. Biochemistry 2014; 53:1768-78. [PMID: 24568554 PMCID: PMC3985488 DOI: 10.1021/bi5000146] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
Numerous kinetic, structural, and
theoretical studies have established
that DNA polymerases adjust their domain structures to enclose nucleotides
in their active sites and then rearrange critical active site residues
and substrates for catalysis, with the latter conformational change
acting to kinetically limit the correct nucleotide incorporation rate.
Additionally, structural studies have revealed a large conformational
change between the apoprotein and the DNA–protein binary state
for Y-family DNA polymerases. In previous studies [Xu, C., Maxwell,
B. A., Brown, J. A., Zhang, L., and Suo, Z. (2009) PLoS Biol.7, e1000225], a real-time Förster resonance
energy transfer (FRET) method was developed to monitor the global
conformational transitions of DNA polymerase IV from Sulfolobus
solfataricus (Dpo4), a prototype Y-family enzyme, during
nucleotide binding and incorporation by measuring changes in distance
between locations on the enzyme and the DNA substrate. To elucidate
further details of the conformational transitions of Dpo4 during substrate
binding and catalysis, in this study, the real-time FRET technique
was used to monitor changes in distance between various pairs of locations
in the protein itself. In addition to providing new insight into the
conformational changes as revealed in previous studies, the results
here show that the previously described conformational change between
the apo and DNA-bound states of Dpo4 occurs in a mechanistic step
distinct from initial formation or dissociation of the binary complex
of Dpo4 and DNA.
Collapse
Affiliation(s)
- Brian A Maxwell
- Ohio State Biophysics Program and ‡Department of Chemistry and Biochemistry, The Ohio State University , Columbus, Ohio 43210, United States
| | | | | |
Collapse
|
25
|
Andrabi M, Mizuguchi K, Ahmad S. Conformational changes in DNA-binding proteins: relationships with precomplex features and contributions to specificity and stability. Proteins 2013; 82:841-57. [PMID: 24265157 DOI: 10.1002/prot.24462] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Revised: 10/02/2013] [Accepted: 10/21/2013] [Indexed: 12/22/2022]
Abstract
Both Proteins and DNA undergo conformational changes in order to form functional complexes and also to facilitate interactions with other molecules. These changes have direct implications for the stability and specificity of the complex, as well as the cooperativity of interactions between multiple entities. In this work, we have extensively analyzed conformational changes in DNA-binding proteins by superimposing DNA-bound and unbound pairs of protein structures in a curated database of 90 proteins. We manually examined each of these pairs, unified the authors' annotations, and summarized our observations by classifying conformational changes into six structural categories. We explored a relationship between conformational changes and functional classes, binding motifs, target specificity, biophysical features of unbound proteins, and stability of the complex. In addition, we have also investigated the degree to which the intrinsic flexibility can explain conformational changes in a subset of 52 proteins with high quality coordinate data. Our results indicate that conformational changes in DNA-binding proteins contribute significantly to both the stability of the complex and the specificity of targets recognized by them. We also conclude that most conformational changes occur in proteins interacting with specific DNA targets, even though unbound protein structures may have sufficient information to interact with DNA in a nonspecific manner.
Collapse
Affiliation(s)
| | - Kenji Mizuguchi
- Bioinformatics project, National Institute of Biomedical Innovation, 7-6-8 Saito-Asagi, Ibaraki City, Osaka 567-0085, Japan
| | | |
Collapse
|
26
|
Brenlla A, Markiewicz RP, Rueda D, Romano LJ. Nucleotide selection by the Y-family DNA polymerase Dpo4 involves template translocation and misalignment. Nucleic Acids Res 2013; 42:2555-63. [PMID: 24270793 PMCID: PMC3936744 DOI: 10.1093/nar/gkt1149] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Y-family DNA polymerases play a crucial role in translesion DNA synthesis. Here, we have characterized the binding kinetics and conformational dynamics of the Y-family polymerase Sulfolobus solfataricus P2 DNA polymerase IV (Dpo4) using single-molecule fluorescence. We find that in the absence of dNTPs, the binary complex shuttles between two different conformations within ∼1 s. These data are consistent with prior crystal structures in which the nucleotide binding site is either occupied by the terminal base pair (preinsertion conformation) or empty following Dpo4 translocation by 1 base pair (insertion conformation). Most interestingly, on dNTP binding, only the insertion conformation is observed and the correct dNTP stabilizes this complex compared with the binary complex, whereas incorrect dNTPs destabilize it. However, if the n+1 template base is complementary to the incoming dNTP, a structure consistent with a misaligned template conformation is observed, in which the template base at the n position loops out. This structure provides evidence for a Dpo4 mutagenesis pathway involving a transient misalignment mechanism.
Collapse
Affiliation(s)
- Alfonso Brenlla
- Department of Chemistry, Wayne State University, Detroit, MI 48202, USA, Department of Medicine, Section of Virology, Imperial College London, London W12 0NN, UK and Single Molecule Imaging, MRC Clinical Sciences Center, Imperial College London, London W12 0NN, UK
| | | | | | | |
Collapse
|
27
|
Wang B, Feig M, Cukier RI, Burton ZF. Computational simulation strategies for analysis of multisubunit RNA polymerases. Chem Rev 2013; 113:8546-66. [PMID: 23987500 PMCID: PMC3829680 DOI: 10.1021/cr400046x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Indexed: 12/13/2022]
Affiliation(s)
- Beibei Wang
- Department
of Biochemistry and Molecular Biology, Michigan
State University, East Lansing, Michigan 48824-1319, United States
| | - Michael Feig
- Department
of Biochemistry and Molecular Biology, Michigan
State University, East Lansing, Michigan 48824-1319, United States
- Department
of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Robert I. Cukier
- Department
of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Zachary F. Burton
- Department
of Biochemistry and Molecular Biology, Michigan
State University, East Lansing, Michigan 48824-1319, United States
| |
Collapse
|
28
|
Espinoza-Herrera SJ, Gaur V, Suo Z, Carey PR. Following DNA chain extension and protein conformational changes in crystals of a Y-family DNA polymerase via Raman crystallography. Biochemistry 2013; 52:4881-90. [PMID: 23855392 DOI: 10.1021/bi400524h] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Y-Family DNA polymerases are known to bypass DNA lesions in vitro and in vivo. Sulfolobus solfataricus DNA polymerase (Dpo4) was chosen as a model Y-family enzyme for investigating the mechanism of DNA synthesis in single crystals. Crystals of Dpo4 in complexes with DNA (the binary complex) in the presence or absence of an incoming nucleotide were analyzed by Raman microscopy. (13)C- and (15)N-labeled d*CTP, or unlabeled dCTP, were soaked into the binary crystals with G as the templating base. In the presence of the catalytic metal ions, Mg(2+) and Mn(2+), nucleotide incorporation was detected by the disappearance of the triphosphate band of dCTP and the retention of *C modes in the crystal following soaking out of noncovalently bound C(or *C)TP. The addition of the second coded base, thymine, was observed by adding cognate dTTP to the crystal following a single d*CTP addition. Adding these two bases caused visible damage to the crystal that was possibly caused by protein and/or DNA conformational change within the crystal. When d*CTP is soaked into the Dpo4 crystal in the absence of Mn(2+) or Mg(2+), the primer extension reaction did not occur; instead, a ternary protein·template·d*CTP complex was formed. In the Raman difference spectra of both binary and ternary complexes, in addition to the modes of d(*C)CTP, features caused by ring modes from the template/primer bases being perturbed and from the DNA backbone appear, as well as features from perturbed peptide and amino acid side chain modes. These effects are more pronounced in the ternary complex than in the binary complex. Using standardized Raman intensities followed as a function of time, the C(*C)TP population in the crystal was maximal at ∼20 min. These remained unchanged in the ternary complex but declined in the binary complexes as chain incorporation occurred.
Collapse
|
29
|
Maxwell BA, Suo Z. Single-molecule investigation of substrate binding kinetics and protein conformational dynamics of a B-family replicative DNA polymerase. J Biol Chem 2013; 288:11590-600. [PMID: 23463511 DOI: 10.1074/jbc.m113.459982] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Replicative DNA polymerases use a complex, multistep mechanism for efficient and accurate DNA replication as uncovered by intense kinetic and structural studies. Recently, single-molecule fluorescence spectroscopy has provided new insights into real time conformational dynamics utilized by DNA polymerases during substrate binding and nucleotide incorporation. We have used single-molecule Förster resonance energy transfer techniques to investigate the kinetics and conformational dynamics of Sulfolobus solfataricus DNA polymerase B1 (PolB1) during DNA and nucleotide binding. Our experiments demonstrate that this replicative polymerase can bind to DNA in at least three conformations, corresponding to an open and closed conformation of the finger domain as well as a conformation with the DNA substrate bound to the exonuclease active site of PolB1. Additionally, our results show that PolB1 can transition between these conformations without dissociating from a primer-template DNA substrate. Furthermore, we show that the closed conformation is promoted by a matched incoming dNTP but not by a mismatched dNTP and that mismatches at the primer-template terminus lead to an increase in the binding of the DNA to the exonuclease site. Our analysis has also revealed new details of the biphasic dissociation kinetics of the polymerase-DNA binary complex. Notably, comparison of the results obtained in this study with PolB1 with those from similar single-molecule studies with an A-family DNA polymerase suggests mechanistic differences between these polymerases. In summary, our findings provide novel mechanistic insights into protein conformational dynamics and substrate binding kinetics of a high fidelity B-family DNA polymerase.
Collapse
Affiliation(s)
- Brian A Maxwell
- Biophysics Program and the Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, USA
| | | |
Collapse
|
30
|
Abstract
Macromolecular crowding decreases the diffusion rate, shifts the equilibrium of protein-protein and protein-substrate interactions, and changes protein conformational dynamics. Collectively, these effects contribute to enzyme catalysis. Here we describe how crowding may bias the conformational change and dynamics of enzyme populations and in this way affect catalysis. Crowding effects have been studied using artificial crowding agents and in vivo-like environments. These studies revealed a correlation between protein dynamics and function in the crowded environment. We suggest that crowded environments be classified into uniform crowding and structured crowding. Uniform crowding represents random crowding conditions created by synthetic particles with a narrow size distribution. Structured crowding refers to the highly coordinated cellular environment, where proteins and other macromolecules are clustered and organized. In structured crowded environments the perturbation of protein thermal stability may be lower; however, it may still be able to modulate functions effectively and dynamically. Dynamic, allosteric enzymes could be more sensitive to cellular perturbations if their free energy landscape is flatter around the native state; on the other hand, if their free energy landscape is rougher, with high kinetic barriers separating deep minima, they could be more robust. Above all, cells are structured; and this holds both for the cytosol and for the membrane environment. The crowded environment is organized, which limits the search, and the crowders are not necessarily inert. More likely, they too transmit allosteric effects, and as such play important functional roles. Overall, structured cellular crowding may lead to higher enzyme efficiency and specificity.
Collapse
Affiliation(s)
- Judith Klinman
- Department of Chemistry Department of Molecular and Cell Biology, University of California The california institute for Quantitativ, Berkeley, CA, USA
| | | |
Collapse
|
31
|
Lin HK, Chase SF, Laue TM, Jen-Jacobson L, Trakselis MA. Differential temperature-dependent multimeric assemblies of replication and repair polymerases on DNA increase processivity. Biochemistry 2012; 51:7367-82. [PMID: 22906116 DOI: 10.1021/bi300956t] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Differentiation of binding accurate DNA replication polymerases over error prone DNA lesion bypass polymerases is essential for the proper maintenance of the genome. The hyperthermophilic archaeal organism Sulfolobus solfataricus (Sso) contains both a B-family replication (Dpo1) and a Y-family repair (Dpo4) polymerase and serves as a model system for understanding molecular mechanisms and assemblies for DNA replication and repair protein complexes. Protein cross-linking, isothermal titration calorimetry, and analytical ultracentrifugation have confirmed a previously unrecognized dimeric Dpo4 complex bound to DNA. Binding discrimination between these polymerases on model DNA templates is complicated by the fact that multiple oligomeric species are influenced by concentration and temperature. Temperature-dependent fluorescence anisotropy equilibrium binding experiments were used to separate discrete binding events for the formation of trimeric Dpo1 and dimeric Dpo4 complexes on DNA. The associated equilibria are found to be temperature-dependent, generally leading to improved binding at higher temperatures for both polymerases. At high temperatures, DNA binding of Dpo1 monomer is favored over binding of Dpo4 monomer, but binding of Dpo1 trimer is even more strongly favored over binding of Dpo4 dimer, thus providing thermodynamic selection. Greater processivities of nucleotide incorporation for trimeric Dpo1 and dimeric Dpo4 are also observed at higher temperatures, providing biochemical validation for the influence of tightly bound oligomeric polymerases. These results separate, quantify, and confirm individual and sequential processes leading to the formation of oligomeric Dpo1 and Dpo4 assemblies on DNA and provide for a concentration- and temperature-dependent discrimination of binding undamaged DNA templates at physiological temperatures.
Collapse
Affiliation(s)
- Hsiang-Kai Lin
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | | | | | | | | |
Collapse
|
32
|
Wang Y, Chu X, Suo Z, Wang E, Wang J. Multidomain protein solves the folding problem by multifunnel combined landscape: theoretical investigation of a Y-family DNA polymerase. J Am Chem Soc 2012; 134:13755-64. [PMID: 22827444 DOI: 10.1021/ja3045663] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Approximately three-fourths of eukaryotic proteins are composed of multiple independently folded domains. However, much of our understanding is based on single domain proteins or isolated domains whose studies directly lead to well-known energy landscape theory in which proteins fold by navigating through a funneled energy landscape toward native structure ensembles. The degrees of freedom for proteins with multiple domains are many orders of magnitude larger than that for single domain proteins. Now, the question arises: How do the multidomain proteins solve the "protein folding problem"? Here, we specifically address this issue by exploring the structure folding relationship of Sulfolobus solfataricus DNA polymerase IV (DPO4), a prototype Y-family DNA polymerase which contains a polymerase core consisting of a palm (P domain), a finger (F domain), and a thumb domain (T domain) in addition to a little finger domain (LF domain). The theoretical results are in good agreement with the experimental data and lead to several theoretical predictions. Finally, we propose that for rapid folding into well-defined conformations which carry out the biological functions, four-domain DPO4 employs a divide-and-conquer strategy, that is, combining multiple individual folding funnels into a single funnel (domains fold independently and then coalesce). In this way, the degrees of freedom for multidomain proteins are polynomial rather than exponential, and the conformational search process can be reduced effectively from a large to a smaller time scale.
Collapse
Affiliation(s)
- Yong Wang
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin, 130022, PR China
| | | | | | | | | |
Collapse
|
33
|
Sherrer SM, Maxwell BA, Pack LR, Fiala KA, Fowler JD, Zhang J, Suo Z. Identification of an unfolding intermediate for a DNA lesion bypass polymerase. Chem Res Toxicol 2012; 25:1531-40. [PMID: 22667759 DOI: 10.1021/tx3002115] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Sulfolobus solfataricus DNA Polymerase IV (Dpo4), a prototype Y-family DNA polymerase, has been well characterized biochemically and biophysically at 37 °C or lower temperatures. However, the physiological temperature of the hyperthermophile S. solfataricus is approximately 80 °C. With such a large discrepancy in temperature, the in vivo relevance of these in vitro studies of Dpo4 has been questioned. Here, we employed circular dichroism spectroscopy and fluorescence-based thermal scanning to investigate the secondary structural changes of Dpo4 over a temperature range from 26 to 119 °C. Dpo4 was shown to display a high melting temperature characteristic of hyperthermophiles. Unexpectedly, the Little Finger domain of Dpo4, which is only found in the Y-family DNA polymerases, was shown to be more thermostable than the polymerase core. More interestingly, Dpo4 exhibited a three-state cooperative unfolding profile with an unfolding intermediate. The linker region between the Little Finger and Thumb domains of Dpo4 was found to be a source of structural instability. Through site-directed mutagenesis, the interactions between the residues in the linker region and the Palm domain were identified to play a critical role in the formation of the unfolding intermediate. Notably, the secondary structure of Dpo4 was not altered when the temperature was increased from 26 to 87.5 °C. Thus, in addition to providing structural insights into the thermal stability and an unfolding intermediate of Dpo4, our work also validated the relevance of the in vitro studies of Dpo4 performed at temperatures significantly lower than 80 °C.
Collapse
Affiliation(s)
- Shanen M Sherrer
- Department of Biochemistry, The Ohio State University, Columbus, OH 43210, USA
| | | | | | | | | | | | | |
Collapse
|
34
|
Maxwell BA, Xu C, Suo Z. DNA lesion alters global conformational dynamics of Y-family DNA polymerase during catalysis. J Biol Chem 2012; 287:13040-7. [PMID: 22362779 DOI: 10.1074/jbc.m112.345835] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A major product of oxidative damage to DNA, 8-oxo-7,8-dihydro-2'-deoxyguanine (8-oxoG), can lead to genomic mutations if it is bypassed unfaithfully by DNA polymerases in vivo. However, our pre-steady-state kinetic studies show that DNA polymerase IV (Dpo4), a prototype Y-family enzyme from Sulfolobus solfataricus, can bypass 8-oxoG both efficiently and faithfully. For the first time, our stopped-flow FRET studies revealed that a DNA polymerase altered its synchronized global conformational dynamics in response to a DNA lesion. Relative to nucleotide incorporation into undamaged DNA, three of the four domains of Dpo4 undertook different conformational transitions during 8-oxoG bypass and the subsequent extension step. Moreover, the rapid translocation of Dpo4 along DNA induced by nucleotide binding was significantly hindered by the interactions between the embedded 8-oxoG and Dpo4 during the extension step. These results unprecedentedly demonstrate that a Y-family DNA polymerase employs different global conformational dynamics when replicating undamaged and damaged DNA.
Collapse
Affiliation(s)
- Brian A Maxwell
- Biophysics Program, The Ohio State University, Columbus, Ohio 43210, USA
| | | | | |
Collapse
|
35
|
Xu PC, Hao J, Chen M, Cui Z, Zhao MH. Influence of myeloperoxidase-catalyzing reaction on the binding between myeloperoxidase and anti-myeloperoxidase antibodies. Hum Immunol 2012; 73:364-9. [PMID: 22374326 DOI: 10.1016/j.humimm.2012.02.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2011] [Revised: 01/01/2012] [Accepted: 02/01/2012] [Indexed: 11/17/2022]
Abstract
In the current study, whether myeloperoxidase (MPO)-catalyzing reaction could influence the antigenicity of MPO was investigated. Hypochlorite acid, the main product of the catalytic reaction, could lower the binding between MPO-antineutrophil cytoplasmic antibodies (ANCA) and MPO when the available chlorine was higher than 0.031×10(-3) g/l. After MPO-catalyzing reaction with H(2)O(2) lower than 0.469 g/l, the binding level between MPO-ANCAcontaining plasma and MPO increased slightly. The peak binding level was 1.135 ± 0.205 (expressed by the absorbance value at 405 nm). However, with the existence of hydrogen donor (o-phenylenediamine) in the reaction system, the peak binding level between MPO-ANCA-containing plasma and post-catalyzing MPO was significantly higher (1.367 ± 0.321 vs 1.135 ± 0.205, p = 0.023). Moreover, at the approximately physical concentration of H(2)O(2) (0.02 g/l), MPO-ANCA exhibited higher titer to post-catalyzing MPO than to pre-catalyzing MPO (3.91 ± 0.84 vs 3.57 ± 0.84, p < 0.001, expressed as the lgT). These data demonstrated that MPO-catalyzing reaction could potentially increase the antigenicity of MPO.
Collapse
Affiliation(s)
- Peng-Cheng Xu
- Renal Division, Department of Medicine, Peking University First Hospital, Institute of Nephrology, Peking University, Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, China
| | | | | | | | | |
Collapse
|
36
|
Brown JA, Pack LR, Fowler JD, Suo Z. Presteady state kinetic investigation of the incorporation of anti-hepatitis B nucleotide analogues catalyzed by noncanonical human DNA polymerases. Chem Res Toxicol 2011; 25:225-33. [PMID: 22132702 DOI: 10.1021/tx200458s] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Antiviral nucleoside analogues have been developed to inhibit the enzymatic activities of the hepatitis B virus (HBV) polymerase, thereby preventing the replication and production of HBV. However, the usage of these analogues can be limited by drug toxicity because the 5'-triphosphates of these nucleoside analogues (nucleotide analogues) are potential substrates for human DNA polymerases to incorporate into host DNA. Although they are poor substrates for human replicative DNA polymerases, it remains to be established whether these nucleotide analogues are substrates for the recently discovered human X- and Y-family DNA polymerases. Using presteady state kinetic techniques, we have measured the substrate specificity values for human DNA polymerases β, λ, η, ι, κ, and Rev1 incorporating the active forms of the following anti-HBV nucleoside analogues approved for clinical use: adefovir, tenofovir, lamivudine, telbivudine, and entecavir. Compared to the incorporation of a natural nucleotide, most of the nucleotide analogues were incorporated less efficiently (2 to >122,000) by the six human DNA polymerases. In addition, the potential for entecavir and telbivudine, two drugs which possess a 3'-hydroxyl, to become embedded into human DNA was examined by primer extension and DNA ligation assays. These results suggested that telbivudine functions as a chain terminator, while entecavir was efficiently extended by the six enzymes and was a substrate for human DNA ligase I. Our findings suggested that incorporation of anti-HBV nucleotide analogues catalyzed by human X- and Y-family polymerases may contribute to clinical toxicity.
Collapse
Affiliation(s)
- Jessica A Brown
- Department of Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | | | | | | |
Collapse
|
37
|
Ma D, Fowler JD, Suo Z. Backbone assignment of the little finger domain of a Y-family DNA polymerase. BIOMOLECULAR NMR ASSIGNMENTS 2011; 5:195-198. [PMID: 21337030 DOI: 10.1007/s12104-011-9298-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2010] [Accepted: 02/10/2011] [Indexed: 05/30/2023]
Abstract
Sulfolobus solfataricus DNA polymerase IV (Dpo4), a prototype Y-family DNA polymerase, contains a unique little finger domain besides a catalytic core. Here, we report the chemical shift assignments for the backbone nitrogens, α and β carbons, and amide protons of the little finger domain of Dpo4. This work and our published backbone assignment for the catalytic core provide the basis for investigating the conformational dynamics of Dpo4 during catalysis using solution NMR spectroscopy.
Collapse
Affiliation(s)
- Dejian Ma
- Department of Biochemistry, The Ohio State University, Zucai Suo, 880 Biological Sciences, 484 West 12th Ave., Columbus, OH 43210, USA
| | | | | |
Collapse
|
38
|
Stevens JA, Link JJ, Zang C, Wang L, Zhong D. Ultrafast dynamics of nonequilibrium resonance energy transfer and probing globular protein flexibility of myoglobin. J Phys Chem A 2011; 116:2610-9. [PMID: 21863851 DOI: 10.1021/jp206106j] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Protein structural plasticity is critical to many biological activities and accurate determination of its temporal and spatial fluctuations is challenging and difficult. Here, we report our extensive characterization of global flexibility of a globular heme protein of myoglobin using resonance energy transfer as a molecular ruler. With site-directed mutagenesis, we use a tryptophan scan to examine local structural fluctuations from B to H helices utilizing 10 tryptophan-heme energy transfer pairs with femtosecond resolution. We observed ultrafast resonance energy transfer dynamics by following a nearly single exponential behavior in 10-100 ps, strongly indicating that the globular structure of myoglobin is relatively rigid, with no observable static or slow dynamic conformational heterogeneity. The observation is against our molecular dynamics simulations, which show large local fluctuations and give multiple exponential energy transfer behaviors, suggesting too flexible of the global structure and thus raising a serious issue of the force fields used in simulations. Finally, these ultrafast energy transfer dynamics all occur on the similar time scales of local environmental relaxations (solvation), leading to nonexponential processes caused by energy relaxations, not structural fluctuations. Our analyses of such processes reveal an intrinsic compressed- and/or stretched-exponential behaviors and elucidate the nature of inherent nonequilibrium of ultrafast resonance energy transfer in proteins. This new concept of compressed nonequilibrium transfer dynamics should be applied to all protein studies by time-resolved Förster resonance energy transfer (FRET).
Collapse
Affiliation(s)
- Jeffrey A Stevens
- Department of Physics, OSU Biophysics Program, 191 West Woodruff Avenue, The Ohio State University, Columbus, Ohio 43210, USA
| | | | | | | | | |
Collapse
|
39
|
Xie P. A nucleotide binding rectification Brownian ratchet model for translocation of Y-family DNA polymerases. Theor Biol Med Model 2011; 8:22. [PMID: 21699732 PMCID: PMC3138451 DOI: 10.1186/1742-4682-8-22] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2011] [Accepted: 06/24/2011] [Indexed: 02/06/2023] Open
Abstract
Y-family DNA polymerases are characterized by low-fidelity synthesis on undamaged DNA and ability to catalyze translesion synthesis over the damaged DNA. Their translocation along the DNA template is an important event during processive DNA synthesis. In this work we present a Brownian ratchet model for this translocation, where the directed translocation is rectified by the nucleotide binding to the polymerase. Using the model, different features of the available structures for Dpo4, Dbh and polymerase ι in binary and ternary forms can be easily explained. Other dynamic properties of the Y-family polymerases such as the fast translocation event upon dNTP binding for Dpo4 and the considerable variations of the processivity among the polymerases can also be well explained by using the model. In addition, some predicted results of the DNA synthesis rate versus the external force acting on Dpo4 and Dbh polymerases are presented. Moreover, we compare the effect of the external force on the DNA synthesis rate of the Y-family polymerase with that of the replicative DNA polymerase.
Collapse
Affiliation(s)
- Ping Xie
- Key Laboratory of Soft Matter Physics and Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
| |
Collapse
|
40
|
Zahn KE, Tchesnokov EP, Götte M, Doublié S. Phosphonoformic acid inhibits viral replication by trapping the closed form of the DNA polymerase. J Biol Chem 2011; 286:25246-55. [PMID: 21566148 DOI: 10.1074/jbc.m111.248864] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Phosphonoformic acid (PFA, foscarnet) belongs to a class of antiviral drugs that inhibit the human cytomegalovirus DNA polymerase (UL54) by mimicking the pyrophosphate leaving group of the nucleotide transfer reaction. Difficulties expressing UL54 have hampered investigation of the precise structural requirements rendering inhibition by this drug. However, a previously engineered chimeric DNA polymerase, constructed by mutating the homologous polymerase from bacteriophage RB69 (gp43) to express several variable elements from UL54, can bypass this obstacle because of its favorable expression and acquired sensitivity to PFA (Tchesnokov, E. P., Obikhod, A., Schinazi, R. F., and Götte, M. (2008) J. Biol. Chem. 283, 34218-34228). Here, we compare two crystal structures that depict the chimeric DNA polymerase with and without PFA bound. PFA is visualized for the first time in the active site of a DNA polymerase, where interactions are resolved between the PP(i) mimic and two basic residues absolutely conserved in the fingers domain of family B polymerases. PFA also chelates metal ion B, the cation that contacts the triphosphate tail of the incoming nucleotide. These DNA complexes utilize a primer-template pair enzymatically chain-terminated by incorporation of acyclo-GMP, the phosphorylated form of the anti-herpes drug acyclovir. We postulate that the V478W mutation present in the chimera is critical in that it pushes the fingers domain to more readily adopt the closed conformation whether or not the drug is bound. The closed state of the fingers domain traps the variant polymerase in the untranslocated state and increases affinity for PFA. This finding provides a model for the mechanism of UL54 stalling by PFA.
Collapse
Affiliation(s)
- Karl E Zahn
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, Vermont 05405, USA
| | | | | | | |
Collapse
|
41
|
Xie P. A model for the dynamics of mammalian family X DNA polymerases. J Theor Biol 2011; 277:111-22. [PMID: 21377475 DOI: 10.1016/j.jtbi.2011.02.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2010] [Revised: 12/22/2010] [Accepted: 02/22/2011] [Indexed: 11/28/2022]
Abstract
Based on available structural studies, a model is presented for polymerization dynamics of mammalian family X DNA polymerases, including polymerases β, λ, μ, and terminal deoxynucleotidyl transferase (TdT). Using the model, distinct polymerization activities and processivities of the four polymerases acting on different forms of DNA substrate are analyzed and studied theoretically. A "gradient" of template dependence of polymerases β, λ, μ, and TdT is well explained. The much higher occurrence frequencies of the -1 frameshift DNA synthesis by pols λ and μ than that by pol β are well explained. The theoretical results on the polymerization processivities are also in agreement with the available experimental data.
Collapse
Affiliation(s)
- Ping Xie
- Key Laboratory of Soft Matter Physics and Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
| |
Collapse
|
42
|
Abstract
To maintain genomic stability, ribonucleotide incorporation during DNA synthesis is controlled predominantly at the DNA polymerase level. A steric clash between the 2'-hydroxyl of an incoming ribonucleotide and a bulky active site residue, known as the "steric gate", establishes an effective mechanism for most DNA polymerases to selectively insert deoxyribonucleotides. Recent kinetic, structural, and in vivo studies have illuminated novel features about ribonucleotide exclusion and the mechanistic consequences of ribonucleotide misincorporation on downstream events, such as the bypass of a ribonucleotide in a DNA template and the subsequent extension of the DNA lesion bypass product. These important findings are summarized in this review.
Collapse
Affiliation(s)
- Jessica A Brown
- Department of Biochemistry, Ohio State University, Columbus, Ohio 43210, United States
| | | |
Collapse
|
43
|
Sherrer SM, Beyer DC, Xia CX, Fowler JD, Suo Z. Kinetic basis of sugar selection by a Y-family DNA polymerase from Sulfolobus solfataricus P2. Biochemistry 2010; 49:10179-86. [PMID: 20973506 DOI: 10.1021/bi101465n] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
DNA polymerases use either a bulky active site residue or a backbone segment to select against ribonucleotides in order to faithfully replicate cellular genomes. Here, we demonstrated that an active site mutation (Y12A) within Sulfolobus solfataricus DNA polymerase IV (Dpo4) caused an average increase of 220-fold in matched ribonucleotide incorporation efficiency and an average decrease of 9-fold in correct deoxyribonucleotide incorporation efficiency, leading to an average reduction of 2000-fold in sugar selectivity. Thus, the bulky side chain of Tyr12 is important for both ribonucleotide discrimination and efficient deoxyribonucleotide incorporation. Other than synthesizing DNA as the wild-type Dpo4, the Y12A Dpo4 mutant incorporated more than 20 consecutive ribonucleotides into primer/template (DNA/DNA) duplexes, suggesting that this mutant protein possesses both a DNA-dependent DNA polymerase activity and a DNA-dependent RNA polymerase activity. Moreover, the binary and ternary crystal structures of Dpo4 have revealed that this DNA lesion bypass polymerase can bind up to eight base pairs of double-stranded DNA which is entirely in B-type. Thus, the DNA binding cleft of Dpo4 is flexible and can accommodate both A- and B-type oligodeoxyribonucleotide duplexes as well as damaged DNA.
Collapse
Affiliation(s)
- Shanen M Sherrer
- Department of Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | | | | | | | | |
Collapse
|
44
|
Ma D, Fowler JD, Yuan C, Suo Z. Backbone assignment of the catalytic core of a Y-family DNA polymerase. BIOMOLECULAR NMR ASSIGNMENTS 2010; 4:207-209. [PMID: 20582735 DOI: 10.1007/s12104-010-9244-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2010] [Accepted: 06/11/2010] [Indexed: 05/29/2023]
Abstract
Sulfolobus solfataricus DNA polymerase IV (Dpo4), a model Y-family DNA polymerase, bypasses DNA lesions. Here, we report the assignments for the backbone nitrogen, carbon, and amide proton NMR signals of Dpo4's catalytic core consisting of the finger, palm, and thumb domains. Our work provides the basis for further NMR spectroscopic studies of the interactions among Dpo4, DNA, and an incoming nucleotide.
Collapse
Affiliation(s)
- Dejian Ma
- Department of Biochemistry, The Ohio State University, 880 Biological Sciences, 484 West 12th Ave., Columbus, OH 43210, USA
| | | | | | | |
Collapse
|
45
|
Ma B, Nussinov R. Enzyme dynamics point to stepwise conformational selection in catalysis. Curr Opin Chem Biol 2010; 14:652-9. [PMID: 20822947 PMCID: PMC6407632 DOI: 10.1016/j.cbpa.2010.08.012] [Citation(s) in RCA: 167] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2010] [Revised: 08/10/2010] [Accepted: 08/10/2010] [Indexed: 12/13/2022]
Abstract
Recent data increasingly reveal that conformational dynamics are indispensable to enzyme function throughout the catalytic cycle, in substrate recruiting, chemical transformation, and product release. Conformational transitions may involve conformational selection and induced fit, which can be viewed as a special case in the catalytic network. NMR, X-ray crystallography, single-molecule FRET, and simulations clearly demonstrate that the free enzyme dynamics already encompass all the conformations necessary for substrate binding, preorganization, transition-state stabilization, and product release. Conformational selection and substate population shift at each step of the catalytic turnover can accommodate enzyme specificity and efficiency. Within such a framework, entropy can have a larger role in conformational dynamics than in direct energy transfer in dynamically promoted catalysis.
Collapse
Affiliation(s)
- Buyong Ma
- Basic Science Program, SAIC-Frederick, Inc., Center for Cancer Research Nanobiology Program, NCI-Frederick, Frederick, MD 21702, USA.
| | | |
Collapse
|
46
|
Chandani S, Jacobs C, Loechler EL. Architecture of y-family DNA polymerases relevant to translesion DNA synthesis as revealed in structural and molecular modeling studies. J Nucleic Acids 2010; 2010. [PMID: 20936174 PMCID: PMC2945684 DOI: 10.4061/2010/784081] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2010] [Accepted: 07/26/2010] [Indexed: 12/22/2022] Open
Abstract
DNA adducts, which block replicative DNA polymerases (DNAPs), are often bypassed by lesion-bypass DNAPs, which are mostly in the Y-Family. Y-Family DNAPs can do non-mutagenic or mutagenic dNTP insertion, and understanding this difference is important, because mutations transform normal into tumorigenic cells. Y-Family DNAP architecture that dictates mechanism, as revealed in structural and modeling studies, is considered. Steps from adduct blockage of replicative DNAPs, to bypass by a lesion-bypass DNAP, to resumption of synthesis by a replicative DNAP are described. Catalytic steps and protein conformational changes are considered. One adduct is analyzed in greater detail: the major benzo[a]pyrene adduct (B[a]P-N2-dG), which is bypassed non-mutagenically (dCTP insertion) by Y-family DNAPs in the IV/κ-class and mutagenically (dATP insertion) by V/η-class Y-Family DNAPs. Important architectural differences between IV/κ-class versus V/η-class DNAPs are discussed, including insights gained by analyzing ~400 sequences each for bacterial DNAPs IV and V, along with sequences from eukaryotic DNAPs kappa, eta and iota. The little finger domains of Y-Family DNAPs do not show sequence conservation; however, their structures are remarkably similar due to the presence of a core of hydrophobic amino acids, whose exact identity is less important than the hydrophobic amino acid spacing.
Collapse
Affiliation(s)
- Sushil Chandani
- Biology Department, Boston University, Boston, MA 02215, USA
| | | | | |
Collapse
|
47
|
Nucleotide sequence determines the accelerated rate of point mutations. Toxicon 2010; 56:295-304. [DOI: 10.1016/j.toxicon.2009.12.022] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2009] [Revised: 12/11/2009] [Accepted: 12/18/2009] [Indexed: 02/07/2023]
|
48
|
Federley RG, Romano LJ. DNA polymerase: structural homology, conformational dynamics, and the effects of carcinogenic DNA adducts. J Nucleic Acids 2010; 2010. [PMID: 20847947 PMCID: PMC2933918 DOI: 10.4061/2010/457176] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2010] [Accepted: 06/30/2010] [Indexed: 01/05/2023] Open
Abstract
DNA replication is vital for an organism to proliferate and lying at the heart of this process is the enzyme DNA polymerase. Most DNA polymerases have a similar three dimensional fold, akin to a human right hand, despite differences in sequence homology. This structural homology would predict a relatively unvarying mechanism for DNA synthesis yet various polymerases exhibit markedly different properties on similar substrates, indicative of each type of polymerase being prescribed to a specific role in DNA replication. Several key conformational steps, discrete states, and structural moieties have been identified that contribute to the array of properties the polymerases exhibit. The ability of carcinogenic adducts to interfere with conformational processes by directly interacting with the protein explicates the mutagenic consequences these adducts impose. Recent studies have identified novel states that have been hypothesised to test the fit of the nascent base pair, and have also shown the enzyme to possess a lively quality by continually sampling various conformations. This review focuses on the homologous structural changes that take place in various DNA polymerases, both replicative and those involved in adduct bypass, the role these changes play in selection of a correct substrate, and how the presence of bulky carcinogenic adducts affects these changes.
Collapse
|
49
|
Brown JA, Zhang L, Sherrer SM, Taylor JS, Burgers PMJ, Suo Z. Pre-Steady-State Kinetic Analysis of Truncated and Full-Length Saccharomyces cerevisiae DNA Polymerase Eta. J Nucleic Acids 2010; 2010. [PMID: 20798853 PMCID: PMC2925389 DOI: 10.4061/2010/871939] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2010] [Accepted: 04/30/2010] [Indexed: 11/23/2022] Open
Abstract
Understanding polymerase fidelity is an important objective towards ascertaining the overall stability of an organism's genome. Saccharomyces cerevisiae DNA polymerase η (yPolη), a Y-family DNA polymerase, is known to efficiently bypass DNA lesions (e.g., pyrimidine dimers) in vivo. Using pre-steady-state kinetic methods, we examined both full-length and a truncated version of yPolη which contains only the polymerase domain. In the absence of yPolη's C-terminal residues 514–632, the DNA binding affinity was weakened by 2-fold and the base substitution fidelity dropped by 3-fold. Thus, the C-terminus of yPolη may interact with DNA and slightly alter the conformation of the polymerase domain during catalysis. In general, yPolη discriminated between a correct and incorrect nucleotide more during the incorporation step (50-fold on average) than the ground-state binding step (18-fold on average). Blunt-end additions of dATP or pyrene nucleotide 5′-triphosphate revealed the importance of base stacking during the binding of incorrect incoming nucleotides.
Collapse
Affiliation(s)
- Jessica A Brown
- Department of Biochemistry, The Ohio State University, Columbus, OH 43210, USA
| | | | | | | | | | | |
Collapse
|