1
|
Wu P, Zehnder J, Schröder N, Blümmel PEW, Salmon L, Damberger FF, Lipps G, Allain FHT, Wiegand T. Initial Primer Synthesis of a DNA Primase Monitored by Real-Time NMR Spectroscopy. J Am Chem Soc 2024; 146:9583-9596. [PMID: 38538061 PMCID: PMC11009956 DOI: 10.1021/jacs.3c11836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 03/17/2024] [Accepted: 03/18/2024] [Indexed: 04/11/2024]
Abstract
Primases are crucial enzymes for DNA replication, as they synthesize a short primer required for initiating DNA replication. We herein present time-resolved nuclear magnetic resonance (NMR) spectroscopy in solution and in the solid state to study the initial dinucleotide formation reaction of archaeal pRN1 primase. Our findings show that the helix-bundle domain (HBD) of pRN1 primase prepares the two substrates and then hands them over to the catalytic domain to initiate the reaction. By using nucleotide triphosphate analogues, the reaction is substantially slowed down, allowing us to study the initial dinucleotide formation in real time. We show that the sedimented protein-DNA complex remains active in the solid-state NMR rotor and that time-resolved 31P-detected cross-polarization experiments allow monitoring the kinetics of dinucleotide formation. The kinetics in the sedimented protein sample are comparable to those determined by solution-state NMR. Protein conformational changes during primer synthesis are observed in time-resolved 1H-detected experiments at fast magic-angle spinning frequencies (100 kHz). A significant number of spectral changes cluster in the HBD pointing to the importance of the HBD for positioning the nucleotides and the dinucleotide.
Collapse
Affiliation(s)
- Pengzhi Wu
- Department
of Biology, Institute of Biochemistry, ETH
Zürich, 8093 Zurich, Switzerland
| | - Johannes Zehnder
- Laboratory
of Physical Chemistry, ETH Zürich, 8093 Zurich, Switzerland
| | - Nina Schröder
- Institute
of Technical and Macromolecular Chemistry, RWTH Aachen University, Worringerweg 2, 52074 Aachen, Germany
| | - Pascal E. W. Blümmel
- Department
of Biology, Institute of Biochemistry, ETH
Zürich, 8093 Zurich, Switzerland
| | - Loïc Salmon
- Department
of Biology, Institute of Biochemistry, ETH
Zürich, 8093 Zurich, Switzerland
| | - Fred. F. Damberger
- Department
of Biology, Institute of Biochemistry, ETH
Zürich, 8093 Zurich, Switzerland
| | - Georg Lipps
- Institute
of Chemistry and Bioanalytics, University
of Applied Sciences Northwestern Switzerland, Hofackerstrasses 30, 4132 Muttenz, Switzerland
| | - Frédéric H.-T. Allain
- Department
of Biology, Institute of Biochemistry, ETH
Zürich, 8093 Zurich, Switzerland
| | - Thomas Wiegand
- Laboratory
of Physical Chemistry, ETH Zürich, 8093 Zurich, Switzerland
- Institute
of Technical and Macromolecular Chemistry, RWTH Aachen University, Worringerweg 2, 52074 Aachen, Germany
- Max-Planck-Institute
for Chemical Energy Conversion, Stiftstr. 34-36, 45470 Mülheim an der Ruhr, Germany
| |
Collapse
|
2
|
Yin Z, Kilkenny ML, Ker DS, Pellegrini L. CryoEM insights into RNA primer synthesis by the human primosome. FEBS J 2024; 291:1813-1829. [PMID: 38335062 DOI: 10.1111/febs.17082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 11/24/2023] [Accepted: 01/26/2024] [Indexed: 02/12/2024]
Abstract
Eukaryotic DNA replication depends on the primosome - a complex of DNA polymerase alpha (Pol α) and primase - to initiate DNA synthesis by polymerisation of an RNA-DNA primer. Primer synthesis requires the tight coordination of primase and polymerase activities. Recent cryo-electron microscopy (cryoEM) analyses have elucidated the extensive conformational transitions required for RNA primer handover between primase and Pol α and primer elongation by Pol α. Because of the intrinsic flexibility of the primosome, however, structural information about the initiation of RNA primer synthesis is still lacking. Here, we capture cryoEM snapshots of the priming reaction to reveal the conformational trajectory of the human primosome that brings DNA primase subunits 1 and 2 (PRIM1 and PRIM2, respectively) together, poised for RNA synthesis. Furthermore, we provide experimental evidence for the continuous association of primase subunit PRIM2 with the RNA primer during primer synthesis, and for how both initiation and termination of RNA primer polymerisation are licenced by specific rearrangements of DNA polymerase alpha catalytic subunit (POLA1), the polymerase subunit of Pol α. Our findings fill a critical gap in our understanding of the conformational changes that underpin the synthesis of the RNA primer by the primosome. Together with existing evidence, they provide a complete description of the structural dynamics of the human primosome during DNA replication initiation.
Collapse
Affiliation(s)
- Zhan Yin
- Department of Biochemistry, University of Cambridge, UK
| | | | - De-Sheng Ker
- Department of Biochemistry, University of Cambridge, UK
| | | |
Collapse
|
3
|
Mullins EA, Salay LE, Durie CL, Bradley NP, Jackman JE, Ohi MD, Chazin WJ, Eichman BF. A mechanistic model of primer synthesis from catalytic structures of DNA polymerase α-primase. Nat Struct Mol Biol 2024:10.1038/s41594-024-01227-4. [PMID: 38491139 DOI: 10.1038/s41594-024-01227-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2023] [Accepted: 01/12/2024] [Indexed: 03/18/2024]
Abstract
The mechanism by which polymerase α-primase (polα-primase) synthesizes chimeric RNA-DNA primers of defined length and composition, necessary for replication fidelity and genome stability, is unknown. Here, we report cryo-EM structures of Xenopus laevis polα-primase in complex with primed templates representing various stages of DNA synthesis. Our data show how interaction of the primase regulatory subunit with the primer 5' end facilitates handoff of the primer to polα and increases polα processivity, thereby regulating both RNA and DNA composition. The structures detail how flexibility within the heterotetramer enables synthesis across two active sites and provide evidence that termination of DNA synthesis is facilitated by reduction of polα and primase affinities for the varied conformations along the chimeric primer-template duplex. Together, these findings elucidate a critical catalytic step in replication initiation and provide a comprehensive model for primer synthesis by polα-primase.
Collapse
Affiliation(s)
- Elwood A Mullins
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
- Center for Structural Biology, Vanderbilt University, Nashville, TN, USA
| | - Lauren E Salay
- Center for Structural Biology, Vanderbilt University, Nashville, TN, USA
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Clarissa L Durie
- Department of Cell and Developmental Biology, University of Michigan School of Medicine, Ann Arbor, MI, USA
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
- Department of Biochemistry, University of Missouri, Columbia, MO, USA
| | - Noah P Bradley
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
- Center for Structural Biology, Vanderbilt University, Nashville, TN, USA
| | - Jane E Jackman
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, USA
- Center for RNA Biology, The Ohio State University, Columbus, OH, USA
| | - Melanie D Ohi
- Department of Cell and Developmental Biology, University of Michigan School of Medicine, Ann Arbor, MI, USA
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Walter J Chazin
- Center for Structural Biology, Vanderbilt University, Nashville, TN, USA.
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA.
- Department of Chemistry, Vanderbilt University, Nashville, TN, USA.
| | - Brandt F Eichman
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA.
- Center for Structural Biology, Vanderbilt University, Nashville, TN, USA.
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA.
| |
Collapse
|
4
|
Baranovskiy AG, Morstadt LM, Babayeva ND, Tahirov TH. Human primosome requires replication protein A when copying DNA with inverted repeats. bioRxiv 2024:2024.03.11.584335. [PMID: 38559116 PMCID: PMC10979909 DOI: 10.1101/2024.03.11.584335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
The human primosome, a four-subunit complex of primase and DNA polymerase alpha (Polα), initiates DNA synthesis on both chromosome strands by generating chimeric RNA-DNA primers for loading DNA polymerases delta and epsilon (Polε). Replication protein A (RPA) tightly binds to single-stranded DNA strands, protecting them from nucleolytic digestion and unauthorized transactions. We report here that RPA plays a critical role for the human primosome during DNA synthesis across inverted repeats prone to hairpin formation. On other alternatively structured DNA forming a G-quadruplex, RPA provides no assistance for primosome. A stimulatory effect of RPA on DNA synthesis across hairpins was also observed for the catalytic domain of Polα but not of Polε. The important factors for an efficient hairpin bypass by primosome are the high affinity of RPA to DNA based on four DNA-binding domains and the interaction of the winged-helix-turn-helix domain of RPA with Polα. Binding studies indicate that this interaction stabilizes the RPA/Polα complex on the primed template. This work provides insight into a cooperative action of RPA and primosome on DNA, which is critical for DNA synthesis across inverted repeats.
Collapse
|
5
|
Shaw AE, Whitted JE, Mihelich MN, Reitman HJ, Timmerman AJ, Schauer GD. Revised Mechanism of Hydroxyurea Induced Cell Cycle Arrest and an Improved Alternative. bioRxiv 2024:2024.03.02.583010. [PMID: 38496404 PMCID: PMC10942336 DOI: 10.1101/2024.03.02.583010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
Replication stress describes various types of endogenous and exogenous challenges to DNA replication in S-phase. Stress during this critical process results in helicase-polymerase decoupling at replication forks, triggering the S-phase checkpoint, which orchestrates global replication fork stalling and delayed entry into G2. The replication stressor most often used to induce the checkpoint response is hydroxyurea (HU), a chemotherapeutic agent. The primary mechanism of S-phase checkpoint activation by HU has thus far been considered to be a reduction of dNTP synthesis by inhibition of ribonucleotide reductase (RNR), leading to helicase-polymerase decoupling and subsequent activation of the checkpoint, mediated by the replisome associated effector kinase Mrc1. In contrast, we observe that HU causes cell cycle arrest in budding yeast independent of both the Mrc1-mediated replication checkpoint response and the Psk1-Mrc1 oxidative signaling pathway. We demonstrate a direct relationship between HU incubation and reactive oxygen species (ROS) production in yeast nuclei. We further observe that ROS strongly inhibits the in vitro polymerase activity of replicative polymerases (Pols), Pol α, Pol δ, and Pol ε, causing polymerase complex dissociation and subsequent loss of DNA substrate binding, likely through oxidation of their integral iron sulfur Fe-S clusters. Finally, we present "RNR-deg," a genetically engineered alternative to HU in yeast with greatly increased specificity of RNR inhibition, allowing researchers to achieve fast, nontoxic, and more readily reversible checkpoint activation compared to HU, avoiding harmful ROS generation and associated downstream cellular effects that may confound interpretation of results.
Collapse
Affiliation(s)
- Alisa E Shaw
- Department of Biochemistry and Molecular Biology, Colorado State University, CO, USA
| | - Jackson E Whitted
- Department of Biochemistry and Molecular Biology, Colorado State University, CO, USA
| | - Mattias N Mihelich
- Department of Biochemistry and Molecular Biology, Colorado State University, CO, USA
| | - Hannah J Reitman
- Department of Biochemistry and Molecular Biology, Colorado State University, CO, USA
| | - Adam J Timmerman
- Department of Biochemistry and Molecular Biology, Colorado State University, CO, USA
| | - Grant D Schauer
- Department of Biochemistry and Molecular Biology, Colorado State University, CO, USA
| |
Collapse
|
6
|
Li Y, Zhu J, Guo Y, Yan R. Structural insight into the assembly and working mechanism of helicase-primase D5 from Mpox virus. Nat Struct Mol Biol 2024; 31:68-81. [PMID: 38177671 DOI: 10.1038/s41594-023-01142-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2023] [Accepted: 09/27/2023] [Indexed: 01/06/2024]
Abstract
The Mpox pandemic, caused by the Mpox virus (or monkeypox virus, MPXV), has gained global attention. The D5 protein, a putative helicase-primase found in MPXV, plays a vital role in viral replication and genome uncoating. Here we determined multiple cryo-EM structures of full-length hexameric D5 in diverse states. These states were captured during ATP hydrolysis while moving along the single-stranded DNA (ssDNA) track. Through comprehensive structural analysis combined with the helicase activity system, we revealed that when the primase domain is truncated or the interaction between the primase and helicase domains is disrupted, the double-stranded DNA (dsDNA) unwinds into ssDNA, suggesting a critical regulatory role of the primase domain. Two transition states bound with ssDNA substrate during unwinding reveals that two ATP molecules were consumed to drive DNA moving forward two nucleotides. Collectively, our findings shed light on the molecular mechanism that links ATP hydrolysis to the DNA unwinding in poxviruses.
Collapse
Affiliation(s)
- Yaning Li
- Department of Biochemistry, School of Medicine, Key University Laboratory of Metabolism and Health of Guangdong, Institute for Biological Electron Microscopy, Southern University of Science and Technology, Shenzhen, China
- Center for Infectious Disease Research, Westlake Laboratory of Life Sciences and Biomedicine, Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, China
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Jing Zhu
- Department of Biochemistry, School of Medicine, Key University Laboratory of Metabolism and Health of Guangdong, Institute for Biological Electron Microscopy, Southern University of Science and Technology, Shenzhen, China
| | - Yingying Guo
- Department of Biochemistry, School of Medicine, Key University Laboratory of Metabolism and Health of Guangdong, Institute for Biological Electron Microscopy, Southern University of Science and Technology, Shenzhen, China.
| | - Renhong Yan
- Department of Biochemistry, School of Medicine, Key University Laboratory of Metabolism and Health of Guangdong, Institute for Biological Electron Microscopy, Southern University of Science and Technology, Shenzhen, China.
| |
Collapse
|
7
|
Cordoba JJ, Mullins EA, Salay LE, Eichman BF, Chazin WJ. Flexibility and Distributive Synthesis Regulate RNA Priming and Handoff in Human DNA Polymerase α-Primase. J Mol Biol 2023; 435:168330. [PMID: 37884206 PMCID: PMC10872500 DOI: 10.1016/j.jmb.2023.168330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 09/22/2023] [Accepted: 10/18/2023] [Indexed: 10/28/2023]
Abstract
DNA replication in eukaryotes relies on the synthesis of a ∼30-nucleotide RNA/DNA primer strand through the dual action of the heterotetrameric polymerase α-primase (pol-prim) enzyme. Synthesis of the 7-10-nucleotide RNA primer is regulated by the C-terminal domain of the primase regulatory subunit (PRIM2C) and is followed by intramolecular handoff of the primer to pol α for extension by ∼20 nucleotides of DNA. Here, we provide evidence that RNA primer synthesis is governed by a combination of the high affinity and flexible linkage of the PRIM2C domain and the surprisingly low affinity of the primase catalytic domain (PRIM1) for substrate. Using a combination of small angle X-ray scattering and electron microscopy, we found significant variability in the organization of PRIM2C and PRIM1 in the absence and presence of substrate, and that the population of structures with both PRIM2C and PRIM1 in a configuration aligned for synthesis is low. Crosslinking was used to visualize the orientation of PRIM2C and PRIM1 when engaged by substrate as observed by electron microscopy. Microscale thermophoresis was used to measure substrate affinities for a series of pol-prim constructs, which showed that the PRIM1 catalytic domain does not bind the template or emergent RNA-primed templates with appreciable affinity. Together, these findings support a model of RNA primer synthesis in which generation of the nascent RNA strand and handoff of the RNA-primed template from primase to polymerase α is mediated by the high degree of inter-domain flexibility of pol-prim, the ready dissociation of PRIM1 from its substrate, and the much higher affinity of the POLA1cat domain of polymerase α for full-length RNA-primed templates.
Collapse
Affiliation(s)
- John J Cordoba
- Chemical and Physical Biology Program, Vanderbilt University, Nashville, TN, USA; Center for Structural Biology, Vanderbilt University, Nashville, TN, USA
| | - Elwood A Mullins
- Center for Structural Biology, Vanderbilt University, Nashville, TN, USA; Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Lauren E Salay
- Chemical and Physical Biology Program, Vanderbilt University, Nashville, TN, USA; Center for Structural Biology, Vanderbilt University, Nashville, TN, USA; Department of Biochemistry, Vanderbilt University, Nashville, TN, USA
| | - Brandt F Eichman
- Chemical and Physical Biology Program, Vanderbilt University, Nashville, TN, USA; Center for Structural Biology, Vanderbilt University, Nashville, TN, USA; Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA; Department of Biochemistry, Vanderbilt University, Nashville, TN, USA
| | - Walter J Chazin
- Chemical and Physical Biology Program, Vanderbilt University, Nashville, TN, USA; Center for Structural Biology, Vanderbilt University, Nashville, TN, USA; Department of Biochemistry, Vanderbilt University, Nashville, TN, USA; Department of Chemistry, Vanderbilt University, Nashville, TN, USA.
| |
Collapse
|
8
|
He Q, Lim CJ. Models for human telomere C-strand fill-in by CST-Polα-primase. Trends Biochem Sci 2023; 48:860-872. [PMID: 37586999 PMCID: PMC10528720 DOI: 10.1016/j.tibs.2023.07.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Revised: 07/12/2023] [Accepted: 07/18/2023] [Indexed: 08/18/2023]
Abstract
Telomere maintenance is essential for the genome integrity of eukaryotes, and this function is underpinned by the two-step telomeric DNA synthesis process: telomere G-overhang extension by telomerase and complementary strand fill-in by DNA polymerase alpha-primase (polα-primase). Compared to the telomerase step, the telomere C-strand fill-in mechanism is less understood. Recent studies have provided new insights into how telomeric single-stranded DNA-binding protein CTC1-STN1-TEN1 (CST) and polα-primase coordinate to synthesize the telomeric C-strand for telomere overhang fill-in. Cryogenic electron microscopy (cryo-EM) structures of CST-polα-primase complexes have provided additional insights into how they assemble at telomeric templates and de novo synthesize the telomere C-strand. In this review, we discuss how these latest findings coalesce with existing understanding to develop a human telomere C-strand fill-in mechanism model.
Collapse
Affiliation(s)
- Qixiang He
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Ci Ji Lim
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA.
| |
Collapse
|
9
|
Zabrady K, Li AWH, Doherty AJ. Mechanism of primer synthesis by Primase-Polymerases. Curr Opin Struct Biol 2023; 82:102652. [PMID: 37459807 DOI: 10.1016/j.sbi.2023.102652] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 05/15/2023] [Accepted: 06/19/2023] [Indexed: 09/16/2023]
Abstract
Members of the primase-polymerase (Prim-Pol) superfamily are found in all domains of life and play diverse roles in genome stability, including primer synthesis during DNA replication, lesion repair and damage tolerance. This review focuses primarily on Prim-Pol members capable of de novo primer synthesis that have experimentally derived structural models available. We discuss the mechanism of DNA primer synthesis initiation by Prim-Pol catalytic domains, based on recent structural and functional studies. We also describe a general model for primer initiation that also includes the ancillary domains/subunits, which stimulate the initiation of primer synthesis.
Collapse
Affiliation(s)
- Katerina Zabrady
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton BN1 9RQ, UK. https://twitter.com/@KZabrady
| | - Arthur W H Li
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton BN1 9RQ, UK
| | - Aidan J Doherty
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton BN1 9RQ, UK.
| |
Collapse
|
10
|
Mullins EA, Salay LE, Durie CL, Bradley NP, Jackman JE, Ohi MD, Chazin WJ, Eichman BF. A mechanistic model of primer synthesis from catalytic structures of DNA polymerase α-primase. bioRxiv 2023:2023.03.16.533013. [PMID: 36993335 PMCID: PMC10055150 DOI: 10.1101/2023.03.16.533013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
The mechanism by which polymerase α-primase (polα-primase) synthesizes chimeric RNA-DNA primers of defined length and composition, necessary for replication fidelity and genome stability, is unknown. Here, we report cryo-EM structures of polα-primase in complex with primed templates representing various stages of DNA synthesis. Our data show how interaction of the primase regulatory subunit with the primer 5'-end facilitates handoff of the primer to polα and increases polα processivity, thereby regulating both RNA and DNA composition. The structures detail how flexibility within the heterotetramer enables synthesis across two active sites and provide evidence that termination of DNA synthesis is facilitated by reduction of polα and primase affinities for the varied conformations along the chimeric primer/template duplex. Together, these findings elucidate a critical catalytic step in replication initiation and provide a comprehensive model for primer synthesis by polα-primase.
Collapse
|
11
|
Maio N, Raza MK, Li Y, Zhang DL, Bollinger JM, Krebs C, Rouault TA. An iron-sulfur cluster in the zinc-binding domain of the SARS-CoV-2 helicase modulates its RNA-binding and -unwinding activities. Proc Natl Acad Sci U S A 2023; 120:e2303860120. [PMID: 37552760 PMCID: PMC10438387 DOI: 10.1073/pnas.2303860120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Accepted: 06/26/2023] [Indexed: 08/10/2023] Open
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of COVID-19, uses an RNA-dependent RNA polymerase along with several accessory factors to replicate its genome and transcribe its genes. Nonstructural protein (nsp) 13 is a helicase required for viral replication. Here, we found that nsp13 ligates iron, in addition to zinc, when purified anoxically. Using inductively coupled plasma mass spectrometry, UV-visible absorption, EPR, and Mössbauer spectroscopies, we characterized nsp13 as an iron-sulfur (Fe-S) protein that ligates an Fe4S4 cluster in the treble-clef metal-binding site of its zinc-binding domain. The Fe-S cluster in nsp13 modulates both its binding to the template RNA and its unwinding activity. Exposure of the protein to the stable nitroxide TEMPOL oxidizes and degrades the cluster and drastically diminishes unwinding activity. Thus, optimal function of nsp13 depends on a labile Fe-S cluster that is potentially targetable for COVID-19 treatment.
Collapse
Affiliation(s)
- Nunziata Maio
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD20892
| | - Md Kausar Raza
- Department of Chemistry, The Pennsylvania State University, University Park, PA16802
| | - Yan Li
- National Institute of Neurological Disorders and Stroke, NIH, Proteomics Core Facility, Bethesda, MD20892
| | - De-Liang Zhang
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD20892
| | - J. Martin Bollinger
- Department of Chemistry, The Pennsylvania State University, University Park, PA16802
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA16802
| | - Carsten Krebs
- Department of Chemistry, The Pennsylvania State University, University Park, PA16802
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA16802
| | - Tracey A. Rouault
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD20892
| |
Collapse
|
12
|
Boldinova EO, Baranovskiy AG, Gagarinskaya DI, Manukyan A, Makarova A, Tahirov T. The role of catalytic and regulatory domains of human PrimPol in DNA binding and synthesis. Nucleic Acids Res 2023; 51:7541-7551. [PMID: 37326028 PMCID: PMC10415149 DOI: 10.1093/nar/gkad507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 04/28/2023] [Accepted: 05/31/2023] [Indexed: 06/17/2023] Open
Abstract
Human PrimPol possesses DNA primase and DNA polymerase activities and restarts stalled replication forks protecting cells against DNA damage in nuclei and mitochondria. The zinc-binding motif (ZnFn) of the C-terminal domain (CTD) of PrimPol is required for DNA primase activity but the mechanism is not clear. In this work, we biochemically demonstrate that PrimPol initiates de novo DNA synthesis in cis-orientation, when the N-terminal catalytic domain (NTD) and the CTD of the same molecule cooperate for substrates binding and catalysis. The modeling studies revealed that PrimPol uses a similar mode of initiating NTP coordination as the human primase. The ZnFn motif residue Arg417 is required for binding the 5'-triphosphate group that stabilizes the PrimPol complex with a DNA template-primer. We found that the NTD alone is able to initiate DNA synthesis, and the CTD stimulates the primase activity of NTD. The regulatory role of the RPA-binding motif in the modulation of PrimPol binding to DNA is also demonstrated.
Collapse
Affiliation(s)
- Elizaveta O Boldinova
- Institute of Molecular Genetics, National Research Center "Kurchatov Institute", Kurchatov sq. 2, 123182 Moscow, Russia
- Institute of Gene Biology, Russian Academy of Sciences, Vavilov 34/5, 119334 Moscow, Russia
| | - Andrey G Baranovskiy
- Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Diana I Gagarinskaya
- Institute of Molecular Genetics, National Research Center "Kurchatov Institute", Kurchatov sq. 2, 123182 Moscow, Russia
- Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Anna A Manukyan
- Institute of Molecular Genetics, National Research Center "Kurchatov Institute", Kurchatov sq. 2, 123182 Moscow, Russia
- Institute of Gene Biology, Russian Academy of Sciences, Vavilov 34/5, 119334 Moscow, Russia
| | - Alena V Makarova
- Institute of Molecular Genetics, National Research Center "Kurchatov Institute", Kurchatov sq. 2, 123182 Moscow, Russia
- Institute of Gene Biology, Russian Academy of Sciences, Vavilov 34/5, 119334 Moscow, Russia
| | - Tahir H Tahirov
- Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198, USA
| |
Collapse
|
13
|
Cordoba JJ, Mullins EA, Salay LE, Eichman BF, Chazin WJ. Flexibility and distributive synthesis regulate RNA priming and handoff in human DNA polymerase α-primase. bioRxiv 2023:2023.08.01.551538. [PMID: 37577606 PMCID: PMC10418221 DOI: 10.1101/2023.08.01.551538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
DNA replication in eukaryotes relies on the synthesis of a ~30-nucleotide RNA/DNA primer strand through the dual action of the heterotetrameric polymerase α-primase (pol-prim) enzyme. Synthesis of the 7-10-nucleotide RNA primer is regulated by the C-terminal domain of the primase regulatory subunit (PRIM2C) and is followed by intramolecular handoff of the primer to pol α for extension by ~20 nucleotides of DNA. Here we provide evidence that RNA primer synthesis is governed by a combination of the high affinity and flexible linkage of the PRIM2C domain and the low affinity of the primase catalytic domain (PRIM1) for substrate. Using a combination of small angle X-ray scattering and electron microscopy, we found significant variability in the organization of PRIM2C and PRIM1 in the absence and presence of substrate, and that the population of structures with both PRIM2C and PRIM1 in a configuration aligned for synthesis is low. Crosslinking was used to visualize the orientation of PRIM2C and PRIM1 when engaged by substrate as observed by electron microscopy. Microscale thermophoresis was used to measure substrate affinities for a series of pol-prim constructs, which showed that the PRIM1 catalytic domain does not bind the template or emergent RNA-primed templates with appreciable affinity. Together, these findings support a model of RNA primer synthesis in which generation of the nascent RNA strand and handoff of the RNA-primed template from primase to polymerase α is mediated by the high degree of inter-domain flexibility of pol-prim, the ready dissociation of PRIM1 from its substrate, and the much higher affinity of the POLA1cat domain of polymerase α for full-length RNA-primed templates.
Collapse
Affiliation(s)
- John J. Cordoba
- Chemical and Physical Biology Program, Vanderbilt University, Nashville, Tennessee, USA
- Center for Structural Biology, Vanderbilt University, Nashville, Tennessee, USA
| | - Elwood A. Mullins
- Center for Structural Biology, Vanderbilt University, Nashville, Tennessee, USA
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA
| | - Lauren E. Salay
- Chemical and Physical Biology Program, Vanderbilt University, Nashville, Tennessee, USA
- Center for Structural Biology, Vanderbilt University, Nashville, Tennessee, USA
- Department of Biochemistry, Vanderbilt University, Nashville, Tennessee, USA
| | - Brandt F. Eichman
- Chemical and Physical Biology Program, Vanderbilt University, Nashville, Tennessee, USA
- Center for Structural Biology, Vanderbilt University, Nashville, Tennessee, USA
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA
- Department of Biochemistry, Vanderbilt University, Nashville, Tennessee, USA
| | - Walter J. Chazin
- Chemical and Physical Biology Program, Vanderbilt University, Nashville, Tennessee, USA
- Center for Structural Biology, Vanderbilt University, Nashville, Tennessee, USA
- Department of Biochemistry, Vanderbilt University, Nashville, Tennessee, USA
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, USA
| |
Collapse
|
14
|
Bainbridge L, Zabrady K, Doherty A. Primase-polymerases: how to make a primer from scratch. Biosci Rep 2023; 43:BSR20221986. [PMID: 37358261 PMCID: PMC10345425 DOI: 10.1042/bsr20221986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 06/21/2023] [Accepted: 06/26/2023] [Indexed: 06/27/2023] Open
Abstract
To pass on genetic information to the next generation, cells must faithfully replicate their genomes to provide copies for each daughter cell. To synthesise these duplicates, cells employ specialised enzymes called DNA polymerases, which rapidly and accurately replicate nucleic acid polymers. However, most polymerases lack the ability to directly initiate DNA synthesis and required specialised replicases called primases to make short polynucleotide primers, from which they then extend. Replicative primases (eukaryotes and archaea) belong to a functionally diverse enzyme superfamily known as Primase-Polymerases (Prim-Pols), with orthologues present throughout all domains of life. Characterised by a conserved catalytic Prim-Pol domain, these enzymes have evolved various roles in DNA metabolism, including DNA replication, repair, and damage tolerance. Many of these biological roles are fundamentally underpinned by the ability of Prim-Pols to generate primers de novo. This review examines our current understanding of the catalytic mechanisms utilised by Prim-Pols to initiate primer synthesis.
Collapse
Affiliation(s)
- Lewis J. Bainbridge
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton BN1 9RQ, U.K
| | - Katerina Zabrady
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton BN1 9RQ, U.K
| | - Aidan J. Doherty
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton BN1 9RQ, U.K
| |
Collapse
|
15
|
Schneider A, Bergsch J, Lipps G. The monomeric archaeal primase from Nanoarchaeum equitans harbours the features of heterodimeric archaeoeukaryotic primases and primes sequence-specifically. Nucleic Acids Res 2023; 51:5087-5105. [PMID: 37099378 PMCID: PMC10250227 DOI: 10.1093/nar/gkad261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 03/17/2023] [Accepted: 03/29/2023] [Indexed: 04/27/2023] Open
Abstract
The marine thermophilic archaeon Nanoarchaeum equitans possesses a monomeric primase encompassing the conserved domains of the small catalytic and the large regulatory subunits of archaeoeukaryotic heterodimeric primases in one protein chain. The recombinant protein primes on templates containing a triplet with a central thymidine, thus displaying a pronounced sequence specificity typically observed with bacterial type primases only. The N. equitans primase (NEQ395) is a highly active primase enzyme synthesizing short RNA primers. Termination occurs preferentially at about nine nucleotides, as determined by HPLC analysis and confirmed with mass spectrometry. Possibly, the compact monomeric primase NEQ395 represents the minimal archaeoeukaryotic primase and could serve as a functional and structural model of the heterodimeric archaeoeukaryotic primases, whose study is hindered by engagement in protein assemblies and rather low activity.
Collapse
Affiliation(s)
- Andy Schneider
- Institute of Chemistry and Bioanalytics, University of Applied Sciences Northwestern Switzerland, 4132 Muttenz, Switzerland
| | - Jan Bergsch
- Institute of Chemistry and Bioanalytics, University of Applied Sciences Northwestern Switzerland, 4132 Muttenz, Switzerland
| | - Georg Lipps
- Institute of Chemistry and Bioanalytics, University of Applied Sciences Northwestern Switzerland, 4132 Muttenz, Switzerland
| |
Collapse
|
16
|
Nasheuer HP, Onwubiko NO. Lagging Strand Initiation Processes in DNA Replication of Eukaryotes-Strings of Highly Coordinated Reactions Governed by Multiprotein Complexes. Genes (Basel) 2023; 14:genes14051012. [PMID: 37239371 DOI: 10.3390/genes14051012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 04/27/2023] [Accepted: 04/28/2023] [Indexed: 05/28/2023] Open
Abstract
In their influential reviews, Hanahan and Weinberg coined the term 'Hallmarks of Cancer' and described genome instability as a property of cells enabling cancer development. Accurate DNA replication of genomes is central to diminishing genome instability. Here, the understanding of the initiation of DNA synthesis in origins of DNA replication to start leading strand synthesis and the initiation of Okazaki fragment on the lagging strand are crucial to control genome instability. Recent findings have provided new insights into the mechanism of the remodelling of the prime initiation enzyme, DNA polymerase α-primase (Pol-prim), during primer synthesis, how the enzyme complex achieves lagging strand synthesis, and how it is linked to replication forks to achieve optimal initiation of Okazaki fragments. Moreover, the central roles of RNA primer synthesis by Pol-prim in multiple genome stability pathways such as replication fork restart and protection of DNA against degradation by exonucleases during double-strand break repair are discussed.
Collapse
Affiliation(s)
- Heinz Peter Nasheuer
- Centre for Chromosome Biology, Arts & Science Building, Main Concourse, School of Biological and Chemical Sciences, Biochemistry, University of Galway, Distillery Road, H91 TK33 Galway, Ireland
| | - Nichodemus O Onwubiko
- Centre for Chromosome Biology, Arts & Science Building, Main Concourse, School of Biological and Chemical Sciences, Biochemistry, University of Galway, Distillery Road, H91 TK33 Galway, Ireland
| |
Collapse
|
17
|
He Q, Baranovskiy AG, Morstadt LM, Lisova AE, Babayeva ND, Lusk BL, Lim CJ, Tahirov TH. Structures of human primosome elongation complexes. Nat Struct Mol Biol 2023; 30:579-583. [PMID: 37069376 PMCID: PMC10268227 DOI: 10.1038/s41594-023-00971-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 03/20/2023] [Indexed: 04/19/2023]
Abstract
The synthesis of RNA-DNA primer by primosome requires coordination between primase and DNA polymerase α subunits, which is accompanied by unknown architectural rearrangements of multiple domains. Using cryogenic electron microscopy, we solved a 3.6 Å human primosome structure caught at an early stage of RNA primer elongation with deoxynucleotides. The structure confirms a long-standing role of primase large subunit and reveals new insights into how primosome is limited to synthesizing short RNA-DNA primers.
Collapse
Affiliation(s)
- Qixiang He
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Andrey G Baranovskiy
- Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, USA
| | - Lucia M Morstadt
- Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, USA
| | - Alisa E Lisova
- Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, USA
| | - Nigar D Babayeva
- Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, USA
| | - Benjamin L Lusk
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Ci Ji Lim
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA.
| | - Tahir H Tahirov
- Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, USA.
| |
Collapse
|
18
|
Siskos L, Antoniou M, Riado J, Enciso M, Garcia C, Liberti D, Esselink D, Baranovskiy AG, Tahirov TH, Visser RGF, Kormelink R, Bai Y, Schouten HJ. DNA primase large subunit is an essential plant gene for geminiviruses, putatively priming viral ss-DNA replication. Front Plant Sci 2023; 14:1130723. [PMID: 37008458 PMCID: PMC10064052 DOI: 10.3389/fpls.2023.1130723] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 03/03/2023] [Indexed: 06/19/2023]
Abstract
The family of Geminiviridae consists of more than 500 circular single-stranded (ss) DNA viral species that can infect numerous dicot and monocot plants. Geminiviruses replicate their genome in the nucleus of a plant cell, taking advantage of the host's DNA replication machinery. For converting their DNA into double-stranded DNA, and subsequent replication, these viruses rely on host DNA polymerases. However, the priming of the very first step of this process, i.e. the conversion of incoming circular ssDNA into a dsDNA molecule, has remained elusive for almost 30 years. In this study, sequencing of melon (Cucumis melo) accession K18 carrying the Tomato leaf curl New Delhi virus (ToLCNDV) recessive resistance quantitative trait locus (QTL) in chromosome 11, and analyses of DNA sequence data from 100 melon genomes, showed a conservation of a shared mutation in the DNA Primase Large subunit (PRiL) of all accessions that exhibited resistance upon a challenge with ToLCNDV. Silencing of (native) Nicotiana benthamiana PriL and subsequent challenging with three different geminiviruses showed a severe reduction in titers of all three viruses, altogether emphasizing an important role of PRiL in geminiviral replication. A model is presented explaining the role of PriL during initiation of geminiviral DNA replication, i.e. as a regulatory subunit of primase that generates an RNA primer at the onset of DNA replication in analogy to DNA Primase-mediated initiation of DNA replication in all living organisms.
Collapse
Affiliation(s)
- Lampros Siskos
- Laboratory of Plant Breeding, Wageningen University and Research, Wageningen, Netherlands
| | - Maria Antoniou
- Laboratory of Plant Breeding, Wageningen University and Research, Wageningen, Netherlands
| | - Jose Riado
- Sakata Vegetables Europe, Almeria, Spain
| | | | | | | | - Danny Esselink
- Laboratory of Plant Breeding, Wageningen University and Research, Wageningen, Netherlands
| | - Andrey G. Baranovskiy
- Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, United States
| | - Tahir H. Tahirov
- Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, United States
| | - Richard G. F. Visser
- Laboratory of Plant Breeding, Wageningen University and Research, Wageningen, Netherlands
| | - Richard Kormelink
- Laboratory of Virology, Wageningen University and Research, Wageningen, Netherlands
| | - Yuling Bai
- Laboratory of Plant Breeding, Wageningen University and Research, Wageningen, Netherlands
| | - Henk J. Schouten
- Laboratory of Plant Breeding, Wageningen University and Research, Wageningen, Netherlands
| |
Collapse
|
19
|
He Q, Lin X, Chavez BL, Agrawal S, Lusk BL, Lim CJ. Structures of the human CST-Polα-primase complex bound to telomere templates. Nature 2022; 608:826-832. [PMID: 35830881 DOI: 10.1038/s41586-022-05040-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 06/29/2022] [Indexed: 01/26/2023]
Abstract
The mammalian DNA polymerase-α-primase (Polα-primase) complex is essential for DNA metabolism, providing the de novo RNA-DNA primer for several DNA replication pathways1-4 such as lagging-strand synthesis and telomere C-strand fill-in. The physical mechanism underlying how Polα-primase, alone or in partnership with accessory proteins, performs its complicated multistep primer synthesis function is unknown. Here we show that CST, a single-stranded DNA-binding accessory protein complex for Polα-primase, physically organizes the enzyme for efficient primer synthesis. Cryogenic electron microscopy structures of the CST-Polα-primase preinitiation complex (PIC) bound to various types of telomere overhang reveal that template-bound CST partitions the DNA and RNA catalytic centres of Polα-primase into two separate domains and effectively arranges them in RNA-DNA synthesis order. The architecture of the PIC provides a single solution for the multiple structural requirements for the synthesis of RNA-DNA primers by Polα-primase. Several insights into the template-binding specificity of CST, template requirement for assembly of the CST-Polα-primase PIC and activation are also revealed in this study.
Collapse
Affiliation(s)
- Qixiang He
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Xiuhua Lin
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Bianca L Chavez
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Sourav Agrawal
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Benjamin L Lusk
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Ci Ji Lim
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA.
| |
Collapse
|
20
|
Baranovskiy AG, Lisova AE, Morstadt LM, Babayeva ND, Tahirov TH. Insight into RNA-DNA primer length counting by human primosome. Nucleic Acids Res 2022; 50:6264-6270. [PMID: 35689638 PMCID: PMC9226528 DOI: 10.1093/nar/gkac492] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 05/19/2022] [Accepted: 06/08/2022] [Indexed: 11/15/2022] Open
Abstract
The human primosome, a four-subunit complex of primase and DNA polymerase alpha (Polα), synthesizes chimeric RNA–DNA primers of a limited length for DNA polymerases delta and epsilon to initiate DNA replication on both chromosome strands. Despite recent structural insights into the action of its two catalytic centers, the mechanism of DNA synthesis termination is still unclear. Here we report results of functional and structural studies revealing how the human primosome counts RNA–DNA primer length and timely terminates DNA elongation. Using a single-turnover primer extension assay, we defined two factors that determine a mature primer length (∼35-mer): (i) a tight interaction of the C-terminal domain of the DNA primase large subunit (p58C) with the primer 5′-end, and (ii) flexible tethering of p58C and the DNA polymerase alpha catalytic core domain (p180core) to the primosome platform domain by extended linkers. The obtained data allow us to conclude that p58C is a key regulator of all steps of RNA–DNA primer synthesis. The above-described findings provide a notable insight into the mechanism of DNA synthesis termination by a eukaryotic primosome, an important process for ensuring successful primer handover to replication DNA polymerases and for maintaining genome integrity.
Collapse
Affiliation(s)
- Andrey G Baranovskiy
- Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center. University of Nebraska Medical Center, Omaha, NE, USA
| | - Alisa E Lisova
- Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center. University of Nebraska Medical Center, Omaha, NE, USA
| | - Lucia M Morstadt
- Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center. University of Nebraska Medical Center, Omaha, NE, USA
| | - Nigar D Babayeva
- Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center. University of Nebraska Medical Center, Omaha, NE, USA
| | - Tahir H Tahirov
- Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center. University of Nebraska Medical Center, Omaha, NE, USA
| |
Collapse
|
21
|
Salay LE, Blee AM, Raza MK, Gallagher KS, Chen H, Dorfeuille AJ, Barton JK, Chazin WJ. Modification of the 4Fe-4S Cluster Charge Transport Pathway Alters RNA Synthesis by Yeast DNA Primase. Biochemistry 2022; 61:1113-1123. [PMID: 35617695 DOI: 10.1021/acs.biochem.2c00100] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
DNA synthesis during replication begins with the generation of an ∼10-nucleotide primer by DNA primase. Primase contains a redox-active 4Fe-4S cluster in the C-terminal domain of the p58 subunit (p58C). The redox state of this 4Fe-4S cluster can be modulated via the transport of charge through the protein and the DNA substrate (redox switching); changes in the redox state of the cluster alter the ability of p58C to associate with its substrate. The efficiency of redox switching in p58C can be altered by mutating tyrosine residues that bridge the 4Fe-4S cluster and the nucleic acid binding site. Here, we report the effects of mutating bridging tyrosines to phenylalanines in yeast p58C. High-resolution crystal structures show that these mutations, even with six tyrosines simultaneously mutated, do not perturb the three-dimensional structure of the protein. In contrast, measurements of the electrochemical properties on DNA-modified electrodes of p58C containing multiple tyrosine to phenylalanine mutations reveal deficiencies in their ability to engage in DNA charge transport. Significantly, this loss of electrochemical activity correlates with decreased primase activity. While single-site mutants showed modest decreases in activity compared to that of the wild-type primase, the protein containing six mutations exhibited a 10-fold or greater decrease. Thus, many possible tyrosine-mediated pathways for charge transport in yeast p58C exist, but inhibiting these pathways together diminishes the ability of yeast primase to generate primers. These results support a model in which redox switching is essential for primase activity.
Collapse
Affiliation(s)
- Lauren E Salay
- Department of Biochemistry, Vanderbilt University, Nashville, Tennessee 37240, United States.,Center for Structural Biology, Vanderbilt University, Nashville, Tennessee 37240, United States
| | - Alexandra M Blee
- Department of Biochemistry, Vanderbilt University, Nashville, Tennessee 37240, United States.,Center for Structural Biology, Vanderbilt University, Nashville, Tennessee 37240, United States
| | - Md Kausar Raza
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Kaitlyn S Gallagher
- Department of Biochemistry, Vanderbilt University, Nashville, Tennessee 37240, United States.,Center for Structural Biology, Vanderbilt University, Nashville, Tennessee 37240, United States
| | - Huiqing Chen
- Department of Biochemistry, Vanderbilt University, Nashville, Tennessee 37240, United States
| | - Andrew J Dorfeuille
- Center for Structural Biology, Vanderbilt University, Nashville, Tennessee 37240, United States
| | - Jacqueline K Barton
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Walter J Chazin
- Department of Biochemistry, Vanderbilt University, Nashville, Tennessee 37240, United States.,Center for Structural Biology, Vanderbilt University, Nashville, Tennessee 37240, United States.,Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, United States
| |
Collapse
|
22
|
Li AWH, Zabrady K, Bainbridge LJ, Zabrady M, Naseem-Khan S, Berger MB, Kolesar P, Cisneros GA, Doherty AJ. Molecular basis for the initiation of DNA primer synthesis. Nature 2022. [PMID: 35508653 DOI: 10.1038/s41586-022-04695-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 03/28/2022] [Indexed: 11/08/2022]
Abstract
During the initiation of DNA replication, oligonucleotide primers are synthesized de novo by primases and are subsequently extended by replicative polymerases to complete genome duplication. The primase-polymerase (Prim-Pol) superfamily is a diverse grouping of primases, which includes replicative primases and CRISPR-associated primase-polymerases (CAPPs) involved in adaptive immunity1-3. Although much is known about the activities of these enzymes, the precise mechanism used by primases to initiate primer synthesis has not been elucidated. Here we identify the molecular bases for the initiation of primer synthesis by CAPP and show that this mechanism is also conserved in replicative primases. The crystal structure of a primer initiation complex reveals how the incoming nucleotides are positioned within the active site, adjacent to metal cofactors and paired to the templating single-stranded DNA strand, before synthesis of the first phosphodiester bond. Furthermore, the structure of a Prim-Pol complex with double-stranded DNA shows how the enzyme subsequently extends primers in a processive polymerase mode. The structural and mechanistic studies presented here establish how Prim-Pol proteins instigate primer synthesis, revealing the requisite molecular determinants for primer synthesis within the catalytic domain. This work also establishes that the catalytic domain of Prim-Pol enzymes, including replicative primases, is sufficient to catalyse primer formation.
Collapse
|
23
|
Venturelli S, Leischner C, Helling T, Renner O, Burkard M, Marongiu L. Minerals and Cancer: Overview of the Possible Diagnostic Value. Cancers (Basel) 2022; 14:cancers14051256. [PMID: 35267564 PMCID: PMC8909570 DOI: 10.3390/cancers14051256] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 02/23/2022] [Accepted: 02/26/2022] [Indexed: 12/16/2022] Open
Abstract
Simple Summary Minerals are important but often overlooked compounds that are required for a variety of cellular biochemical processes and pathways that regulate cell proliferation. Their dietary imbalance, which is becoming more common in the diets of industrialized countries, is linked to an increased risk of cancer. The current review will present some of the most important minerals for human physiology and evaluate their potential application as cancer biomarkers. Abstract Cancer is the second leading cause of death worldwide and is expected to increase by one-third over the next two decades, in parallel with the growing proportion of the elderly population. Treatment and control of cancer incidence is a global issue. Since there is no clear way to prevent or cure this deadly malignancy, diagnostic, predictive, and prognostic markers for oncological diseases are of great therapeutic value. Minerals and trace elements are important micronutrients for normal physiological function of the body. They are abundant in natural food sources and are regularly included in dietary supplements whereas highly processed industrial food often contains reduced or altered amounts of them. In modern society, the daily intake, storage pools, and homeostasis of these micronutrients are dependent on certain dietary habits and can be thrown out of balance by malignancies. The current work summarizes the data on minerals and trace elements associated with abnormal accumulation or depletion states in tumor patients and discusses their value as potential tumor-associated biomarkers that could be introduced into cancer therapy.
Collapse
Affiliation(s)
- Sascha Venturelli
- Department of Nutritional Biochemistry, Institute of Nutritional Sciences, University of Hohenheim, Garbenstraße 30, 70599 Stuttgart, Germany; (S.V.); (C.L.); (T.H.); (O.R.)
- Department of Vegetative and Clinical Physiology, Institute of Physiology, University of Tuebingen, Wilhelmstraße 56, 72074 Tuebingen, Germany
| | - Christian Leischner
- Department of Nutritional Biochemistry, Institute of Nutritional Sciences, University of Hohenheim, Garbenstraße 30, 70599 Stuttgart, Germany; (S.V.); (C.L.); (T.H.); (O.R.)
| | - Thomas Helling
- Department of Nutritional Biochemistry, Institute of Nutritional Sciences, University of Hohenheim, Garbenstraße 30, 70599 Stuttgart, Germany; (S.V.); (C.L.); (T.H.); (O.R.)
| | - Olga Renner
- Department of Nutritional Biochemistry, Institute of Nutritional Sciences, University of Hohenheim, Garbenstraße 30, 70599 Stuttgart, Germany; (S.V.); (C.L.); (T.H.); (O.R.)
| | - Markus Burkard
- Department of Nutritional Biochemistry, Institute of Nutritional Sciences, University of Hohenheim, Garbenstraße 30, 70599 Stuttgart, Germany; (S.V.); (C.L.); (T.H.); (O.R.)
- Correspondence: (M.B.); (L.M.); Tel.: +49-711-459-23621 (M.B.); +49-711-459-23618 (L.M.)
| | - Luigi Marongiu
- Department of Nutritional Biochemistry, Institute of Nutritional Sciences, University of Hohenheim, Garbenstraße 30, 70599 Stuttgart, Germany; (S.V.); (C.L.); (T.H.); (O.R.)
- Correspondence: (M.B.); (L.M.); Tel.: +49-711-459-23621 (M.B.); +49-711-459-23618 (L.M.)
| |
Collapse
|
24
|
Caserta G, Zuccarello L, Barbosa C, Silveira CM, Moe E, Katz S, Hildebrandt P, Zebger I, Todorovic S. Unusual structures and unknown roles of FeS clusters in metalloenzymes seen from a resonance Raman spectroscopic perspective. Coord Chem Rev 2022; 452:214287. [DOI: 10.1016/j.ccr.2021.214287] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
25
|
Kilkenny ML, Veale CE, Guppy A, Hardwick SW, Chirgadze DY, Rzechorzek NJ, Maman JD, Pellegrini L. Structural basis for the interaction of SARS-CoV-2 virulence factor nsp1 with DNA polymerase α-primase. Protein Sci 2022; 31:333-344. [PMID: 34719824 PMCID: PMC8661717 DOI: 10.1002/pro.4220] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 10/28/2021] [Accepted: 10/28/2021] [Indexed: 11/21/2022]
Abstract
The molecular mechanisms that drive the infection by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-the causative agent of coronavirus disease 2019 (COVID-19)-are under intense current scrutiny to understand how the virus operates and to uncover ways in which the disease can be prevented or alleviated. Recent proteomic screens of the interactions between viral and host proteins have identified the human proteins targeted by SARS-CoV-2. The DNA polymerase α (Pol α)-primase complex or primosome-responsible for initiating DNA synthesis during genomic duplication-was identified as a target of nonstructural protein 1 (nsp1), a major virulence factor in the SARS-CoV-2 infection. Here, we validate the published reports of the interaction of nsp1 with the primosome by demonstrating direct binding with purified recombinant components and providing a biochemical characterization of their interaction. Furthermore, we provide a structural basis for the interaction by elucidating the cryo-electron microscopy structure of nsp1 bound to the primosome. Our findings provide biochemical evidence for the reported targeting of Pol α by the virulence factor nsp1 and suggest that SARS-CoV-2 interferes with Pol α's putative role in the immune response during the viral infection.
Collapse
Affiliation(s)
| | | | - Amir Guppy
- Department of BiochemistryUniversity of CambridgeCambridgeCB2 1GAUK
| | | | | | - Neil J. Rzechorzek
- Department of BiochemistryUniversity of CambridgeCambridgeCB2 1GAUK
- Present address:
The Francis Crick InstituteLondonNW1 1ATUK
| | - Joseph D. Maman
- Department of BiochemistryUniversity of CambridgeCambridgeCB2 1GAUK
| | - Luca Pellegrini
- Department of BiochemistryUniversity of CambridgeCambridgeCB2 1GAUK
| |
Collapse
|
26
|
Maio N, Lafont BAP, Sil D, Li Y, Bollinger JM, Krebs C, Pierson TC, Linehan WM, Rouault TA. Fe-S cofactors in the SARS-CoV-2 RNA-dependent RNA polymerase are potential antiviral targets. Science 2021; 373:236-241. [PMID: 34083449 PMCID: PMC8892629 DOI: 10.1126/science.abi5224] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2021] [Accepted: 05/28/2021] [Indexed: 01/18/2023]
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causal agent of COVID-19, uses an RNA-dependent RNA polymerase (RdRp) for the replication of its genome and the transcription of its genes. We found that the catalytic subunit of the RdRp, nsp12, ligates two iron-sulfur metal cofactors in sites that were modeled as zinc centers in the available cryo-electron microscopy structures of the RdRp complex. These metal binding sites are essential for replication and for interaction with the viral helicase. Oxidation of the clusters by the stable nitroxide TEMPOL caused their disassembly, potently inhibited the RdRp, and blocked SARS-CoV-2 replication in cell culture. These iron-sulfur clusters thus serve as cofactors for the SARS-CoV-2 RdRp and are targets for therapy of COVID-19.
Collapse
Affiliation(s)
- Nunziata Maio
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Bernard A P Lafont
- SARS-CoV-2 Virology Core, Laboratory of Viral Diseases, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Debangsu Sil
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA
| | - Yan Li
- Proteomics Core Facility, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - J Martin Bollinger
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA.,Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Carsten Krebs
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA.,Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Theodore C Pierson
- Laboratory of Viral Diseases, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - W Marston Linehan
- Urologic Oncology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA
| | - Tracey A Rouault
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
| |
Collapse
|
27
|
Zhu M, Wu M, Bian S, Song Q, Xiao M, Huang H, You L, Zhang J, Zhang J, Cheng C, Ni W, Zheng W. DNA primase subunit 1 deteriorated progression of hepatocellular carcinoma by activating AKT/mTOR signaling and UBE2C-mediated P53 ubiquitination. Cell Biosci 2021; 11:42. [PMID: 33622397 PMCID: PMC7903777 DOI: 10.1186/s13578-021-00555-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 02/11/2021] [Indexed: 12/13/2022] Open
Abstract
Background DNA primase subunit 1 (PRIM1) has been reported as a novel oncogene in several cancer types. However, its roles in hepatocellular carcinoma (HCC) remain unclear. This study aimed to investigate underlying mechanisms of PRIM1 and identify it as a potential molecular target for HCC. Methods Hub genes were screened between HCC tissues and normal liver tissues in 3 gene expression omnibus (GEO) datasets and the cancer genome atlas (TCGA). The expression features and prognostic value of one of the hub genes PRIM1 were analyzed by bioinformatic analyses and immunohistochemistry. Loss-of-function and gain-of-function studies were used to investigate the regulatory role of PRIM1 in HCC cells. Real-time (RT)-qPCR, western blotting, and ubiquitin immunoprecipitation assays were performed to explore the underlying mechanisms. The xenograft model was employed to detect the roles of PRIM1 in tumor growth in vivo. Finally, the 3D spheroid model was conducted to validate the role of PRIM1 in tumor growth and sorafenib resistance. Results The hub genes of HCC were screened in multiple bioinformatic datasets. PRIM1, as one of the hub genes, was significantly overexpressed in HCC tissues in mRNA and protein levels. In addition, high expression of PRIM1 indicated poor prognosis of HCC patients in TCGA, ICGC, and Nantong cohorts. Overexpression of PRIM1 promoted the proliferation, migration/invasion, and sorafenib resistance of HCC cells, with the decrease in apoptosis and cell cycle arrest. Mechanically, PRIM1 facilitated epithelial-mesenchymal transition (EMT) process and the activity of PI3K/AKT/mTOR signaling of HCC cells. Additionally, PRIM1 could cause the ubiquitination and degradation of P53 by upregulating Ubiquitin Conjugating Enzyme E2 C (UBE2C). Furthermore, knockdown of PRIM1 significantly inhibited the growth of xenograft tumors and HCC cells-derived spheroids with enhanced sorafenib resistance. Conclusion This study implies that PRIM1 may play a key role in the progression of HCC and may serve as a potential target for HCC treatment.
Collapse
Affiliation(s)
- Mengqi Zhu
- Research Center of Clinical Medicine, Affiliated Hospital of Nantong University, 20 Xisi Road, Nantong, 226001, Jiangsu, China.,School of Medicine, Nantong University, 19 Qixiu Road, Nantong, 226001, Jiangsu, China.,Department of Oncology, Affiliated Hospital of Nantong University, 20 Xisi Road, Nantong, 226001, Jiangsu, China
| | - Mengna Wu
- Research Center of Clinical Medicine, Affiliated Hospital of Nantong University, 20 Xisi Road, Nantong, 226001, Jiangsu, China
| | - Saiyan Bian
- Research Center of Clinical Medicine, Affiliated Hospital of Nantong University, 20 Xisi Road, Nantong, 226001, Jiangsu, China.,School of Medicine, Nantong University, 19 Qixiu Road, Nantong, 226001, Jiangsu, China
| | - Qianqian Song
- Department of Radiology, Wake Forest School of Medicine, One Medical Center Boulevard, Winston-Salem, 27157 NC, USA
| | - Mingbing Xiao
- Research Center of Clinical Medicine, Affiliated Hospital of Nantong University, 20 Xisi Road, Nantong, 226001, Jiangsu, China
| | - Hua Huang
- Research Center of Clinical Medicine, Affiliated Hospital of Nantong University, 20 Xisi Road, Nantong, 226001, Jiangsu, China
| | - Li You
- Research Center of Clinical Medicine, Affiliated Hospital of Nantong University, 20 Xisi Road, Nantong, 226001, Jiangsu, China
| | - Jianping Zhang
- Research Center of Clinical Medicine, Affiliated Hospital of Nantong University, 20 Xisi Road, Nantong, 226001, Jiangsu, China
| | - Jie Zhang
- Department of Oncology, Affiliated Hospital of Nantong University, 20 Xisi Road, Nantong, 226001, Jiangsu, China
| | - Chun Cheng
- School of Medicine, Nantong University, 19 Qixiu Road, Nantong, 226001, Jiangsu, China
| | - Wenkai Ni
- Research Center of Clinical Medicine, Affiliated Hospital of Nantong University, 20 Xisi Road, Nantong, 226001, Jiangsu, China.
| | - Wenjie Zheng
- Research Center of Clinical Medicine, Affiliated Hospital of Nantong University, 20 Xisi Road, Nantong, 226001, Jiangsu, China. .,Department of Oncology, Affiliated Hospital of Nantong University, 20 Xisi Road, Nantong, 226001, Jiangsu, China.
| |
Collapse
|
28
|
Zhang Y, Li L, Liu R, Zeng C. DNA Primase Subunit 1 Expression in Hepatocellular Carcinoma and Its Clinical Implication. Biomed Res Int 2020; 2020:9689312. [PMID: 32908930 DOI: 10.1155/2020/9689312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 08/10/2020] [Indexed: 11/22/2022]
Abstract
DNA Primase Subunit 1 (PRIM1) is crucial for cancer development and progression. However, there remains a lack of comprehension concerning the clinical implication of PRIM1 in HCC. Here, aberrant expression of PRIM1 was identified in HCC according to available databases. The prognostic value of PRIM1 in patients presenting with HCC was further assessed based on TCGA data. Gene set enrichment analysis (GSEA) was subsequently conducted to investigate the potential function of PRIM1. Additionally, the correlations between tumor-infiltrating immune cells (TIICs) and PRIM1 expression were evaluated. The data from TCGA, GEO, ONCOMINE, and HCCDB databases illustrated that PRIM1 was overexpressed in HCC tissues, compared to normal liver tissues (all p < 0.05). Kaplan-Meier analysis revealed that high PRIM1 expression in HCC was closely correlated with worse overall survival (p < 0.05). The univariate and multivariate analyses illustrated that PRIM1 expression was an independent novel prognostic indicator in HCC. Additionally, the area under the receiver operating characteristic (AUROC) curve for PRIM1 reached 0.8651, indicating the diagnostic significance of PRIM1 in patients with HCC. GSEA showed that PRIM1 overexpression was significantly enriched in several tumor-related signaling pathways. Besides, TIIC analysis clarified the association between PRIM1 expression and TIICs in HCC. The findings disclose that PRIM1 profoundly implicated in promoting tumorigenesis might work as a desirable biomarker for HCC.
Collapse
|
29
|
Bhowmik D, Jagadeesan R, Rai P, Nandi R, Gugan K, Kumar D. Evaluation of potential drugs against leishmaniasis targeting catalytic subunit of Leishmania donovani nuclear DNA primase using ligand based virtual screening, docking and molecular dynamics approaches. J Biomol Struct Dyn 2020; 39:1838-1852. [PMID: 32141397 DOI: 10.1080/07391102.2020.1739557] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Leishmania donovani, causes leishmaniasis, a global health trouble with around 89 different countries and its population under its risk. Replication initiation events have been instrumental in regulating the DNA duplication and as the small subunit of L. donovani nuclear DNA primase (Ld-PriS) inherits the catalytic site, it plays a vital role in DNA replication. In this study we have aimed Ld-PriS for the first time as a prospective target for the application of drug against Leishmania parasite. 3-D structures of Ld-PriS were built and ligand-based virtual screening was performed using hybrid similarity recognition techniques. Ligands from the ZINC database were used for the screening purposes based on known DNA primase inhibitor Sphingosine as a query. Top 150 ligands were taken into consideration for molecular docking against the query protein (Ld-PriS) using PyRx and iGEMDOCK softwares. Top five compounds with the best docking score were selected for pharmacokinetic investigation and molecular dynamic simulation. These top five screened inhibitors showed very poor binding affinity toward the catalytic subunit of human primase indicating their safety toward the host normal replication mechanism. The top five compounds showed good pharmacokinetic profiles and ADMET predictions revealed good absorption, solubility, permeability, uniform distribution, proper metabolism, minimal toxicity and good bioavailability. Simulation studies upto 50 ns revealed the three leads ZINC000009219046, ZINC000025998119 and ZINC000004677901 bind with Ld-PriS throughout the simulation and there were no huge variations in their backbone suggesting that these three may play as potential lead compounds for developing new drug against leishmaniasis.Communicated by Ramaswamy H. Sarma.
Collapse
Affiliation(s)
- Deep Bhowmik
- Department of Microbiology, Assam University, Silchar, Assam, India
| | - Rahul Jagadeesan
- CAS in Crystallography and Biophysics, Guindy Campus, University of Madras, Chennai, India
| | - Praveen Rai
- Department of Biotechnology, Central University of Rajasthan, Bandarsindri, India
| | - Rajat Nandi
- Department of Microbiology, Assam University, Silchar, Assam, India
| | - Kothandan Gugan
- CAS in Crystallography and Biophysics, Guindy Campus, University of Madras, Chennai, India
| | - Diwakar Kumar
- Department of Microbiology, Assam University, Silchar, Assam, India
| |
Collapse
|
30
|
Hakeem S, Singh I, Sharma P, Verma V, Chandra R. in silico screening and molecular dynamics simulations study to identify novel potent inhibitors against Mycobacterium tuberculosis DnaG primase. Acta Trop 2019; 199:105154. [PMID: 31445897 DOI: 10.1016/j.actatropica.2019.105154] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 08/15/2019] [Accepted: 08/21/2019] [Indexed: 10/26/2022]
Abstract
Tuberculosis remains a major global health threat killing millions of people. Due to existing multiple drug resistance (MDR) and prolonged treatment it becomes necessary to explore novel drug targets in Mycobacterium tuberculosis (Mtb). DnaG primase, having a significant role in primer synthesis during initiation of DNA replication, has emerged as a promising drug target. The three dimensional (3D) model of its catalytic domain (Toprim) was constructed. Further, in silico screening of the three diverse chemical compound libraries against the modeled domain was carried out. Four top screened compounds were identified and evaluated by ADMET analysis. The stability of these compounds in complex with the Toprim domain was validated through 50 ns molecular dynamics simulations. Lys 101, Glu 137 and Asp 188 in the active site predominantly formed the hydrogen bonds with the top screened compounds. Hence, the drug-like compounds identified can be taken up for the further experimental investigation as anti-tubercular agents.
Collapse
|
31
|
Abstract
It has been known for decades that the principal replicative DNA polymerases that effect genome replication are incapable of starting DNA synthesis de novo. Rather, they require a 3′-OH group from which to extend a DNA chain. Cellular DNA replication systems exploit a dedicated, limited processivity RNA polymerase, termed primase, that synthesizes a short oligoribonucleotide primer which is then extended by a DNA polymerase. Thus, primases can initiate synthesis, proceed with primer elongation for a short distance then transfer the primer to a DNA polymerase. Despite these well-established properties, the mechanistic basis of these dynamic behaviours has only recently been established. In the following, the author will describe recent insights from studies of the related eukaryotic and archaeal DNA primases. Significantly, the general conclusions from these studies likely extend to a broad class of extrachromosomal element-associated primases as well as the human primase-related DNA repair enzyme, PrimPol.
Collapse
|
32
|
Abstract
Despite their relative simplicity, iron-sulfur clusters have been omnipresent as cofactors in myriad cellular processes such as oxidative phosphorylation and other respiratory pathways. Recent research advances confirm the presence of different clusters in enzymes involved in nucleic acid metabolism. Iron-sulfur clusters can therefore be considered hallmarks of cellular metabolism. Helicases, nucleases, glycosylases, DNA polymerases and transcription factors, among others, incorporate various types of clusters that serve differing roles. In this chapter, we review our current understanding of the identity and functions of iron-sulfur clusters in DNA and RNA metabolizing enzymes, highlighting their importance as regulators of cellular function.
Collapse
Affiliation(s)
- Yara Khodour
- Department of Biology and Biochemistry, Birzeit University, West Bank, Palestine
| | - Laurie S Kaguni
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, United States
| | - Johnny Stiban
- Department of Biology and Biochemistry, Birzeit University, West Bank, Palestine.
| |
Collapse
|
33
|
Boudet J, Devillier JC, Wiegand T, Salmon L, Meier BH, Lipps G, Allain FHT. A Small Helical Bundle Prepares Primer Synthesis by Binding Two Nucleotides that Enhance Sequence-Specific Recognition of the DNA Template. Cell 2018; 176:154-166.e13. [PMID: 30595448 DOI: 10.1016/j.cell.2018.11.031] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 09/20/2018] [Accepted: 11/17/2018] [Indexed: 02/08/2023]
Abstract
Primases have a fundamental role in DNA replication. They synthesize a primer that is then extended by DNA polymerases. Archaeoeukaryotic primases require for synthesis a catalytic and an accessory domain, the exact contribution of the latter being unresolved. For the pRN1 archaeal primase, this domain is a 115-amino acid helix bundle domain (HBD). Our structural investigations of this small HBD by liquid- and solid-state nuclear magnetic resonance (NMR) revealed that only the HBD binds the DNA template. DNA binding becomes sequence-specific after a major allosteric change in the HBD, triggered by the binding of two nucleotide triphosphates. The spatial proximity of the two nucleotides and the DNA template in the quaternary structure of the HBD strongly suggests that this small domain brings together the substrates to prepare the first catalytic step of primer synthesis. This efficient mechanism is likely general for all archaeoeukaryotic primases.
Collapse
Affiliation(s)
- Julien Boudet
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zürich, 8093 Zürich, Switzerland.
| | - Jean-Christophe Devillier
- Institute of Chemistry and Bioanalytics, University of Applied Sciences Northwestern Switzerland, Hofackerstrasses 30, 4132 Muttenz, Switzerland
| | - Thomas Wiegand
- Physical Chemistry, ETH Zürich, 8093 Zürich, Switzerland
| | - Loic Salmon
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zürich, 8093 Zürich, Switzerland
| | - Beat H Meier
- Physical Chemistry, ETH Zürich, 8093 Zürich, Switzerland
| | - Georg Lipps
- Institute of Chemistry and Bioanalytics, University of Applied Sciences Northwestern Switzerland, Hofackerstrasses 30, 4132 Muttenz, Switzerland.
| | - Frédéric H-T Allain
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zürich, 8093 Zürich, Switzerland.
| |
Collapse
|
34
|
O'Brien E, Holt ME, Salay LE, Chazin WJ, Barton JK. Substrate Binding Regulates Redox Signaling in Human DNA Primase. J Am Chem Soc 2018; 140:17153-17162. [PMID: 30433774 DOI: 10.1021/jacs.8b09914] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Generation of daughter strands during DNA replication requires the action of DNA primase to synthesize an initial short RNA primer on the single-stranded DNA template. Primase is a heterodimeric enzyme containing two domains whose activity must be coordinated during primer synthesis: an RNA polymerase domain in the small subunit (p48) and a [4Fe4S] cluster-containing C-terminal domain of the large subunit (p58C). Here we examine the redox switching properties of the [4Fe4S] cluster in the full p48/p58 heterodimer using DNA electrochemistry. Unlike with isolated p58C, robust redox signaling in the primase heterodimer requires binding of both DNA and NTPs; NTP binding shifts the p48/p58 cluster redox potential into the physiological range, generating a signal near 160 mV vs NHE. Preloading of primase with NTPs enhances catalytic activity on primed DNA, suggesting that primase configurations promoting activity are more highly populated in the NTP-bound protein. We propose that p48/p58 binding of anionic DNA and NTPs affects the redox properties of the [4Fe4S] cluster; this electrostatic change is likely influenced by the alignment of primase subunits during activity because the configuration affects the [4Fe4S] cluster environment and coupling to DNA bases for redox signaling. Thus, both binding of polyanionic substrates and configurational dynamics appear to influence [4Fe4S] redox signaling properties. These results suggest that these factors should be considered generally in characterizing signaling networks of large, multisubunit DNA-processing [4Fe4S] enzymes.
Collapse
Affiliation(s)
- Elizabeth O'Brien
- Division of Chemistry and Chemical Engineering , California Institute of Technology , Pasadena , California 91125 , United States
| | - Marilyn E Holt
- Departments of Biochemistry and Chemistry, Center for Structural Biology , Vanderbilt University , Nashville , Tennessee 37240 , United States
| | - Lauren E Salay
- Departments of Biochemistry and Chemistry, Center for Structural Biology , Vanderbilt University , Nashville , Tennessee 37240 , United States
| | - Walter J Chazin
- Departments of Biochemistry and Chemistry, Center for Structural Biology , Vanderbilt University , Nashville , Tennessee 37240 , United States
| | - Jacqueline K Barton
- Division of Chemistry and Chemical Engineering , California Institute of Technology , Pasadena , California 91125 , United States
| |
Collapse
|
35
|
Lee WH, Chen LC, Lee CJ, Huang CC, Ho YS, Yang PS, Ho CT, Chang HL, Lin IH, Chang HW, Liu YR, Wu CH, Tu SH. DNA primase polypeptide 1 (PRIM1) involves in estrogen-induced breast cancer formation through activation of the G2/M cell cycle checkpoint. Int J Cancer 2018; 144:615-630. [PMID: 30097999 DOI: 10.1002/ijc.31788] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 07/24/2018] [Indexed: 12/22/2022]
Abstract
The DNA primase polypeptide 1 (PRIM1) is responsible for synthesizing small RNA primers for Okazaki fragments generated during discontinuous DNA replication. PRIM1 mRNA expression levels in breast tumor samples were detected by real-time PCR analysis. Xenografted tumor model was established to study the carcinogenic role of PRIM1 and its potential therapeutic applications. The average PRIM1 mRNA (copy number × 103 /μg) expression was 4.7-fold higher in tumors than in normal tissue (*p = 0.005, n = 254). PRIM1 was detected preferentially at a higher level (>40-fold) in poorly differentiated tumor tissues (n = 46) compared with more highly differentiated tumors tissues (n = 10) (*p = 0.005). Poor overall survival rate was correlated to the estrogen receptor positive (ER+, n = 20) patients with higher PRIM1 expression when compare to the ER- (n = 10) patients (Chi Square test, p = 0.03). Stable expression of PRIM1-siRNA in the ER+ BT-474 cells-xenograft tumors significantly reduced tumor volume in SCID mice (*p = 0.005). The anti-tumoral effects of inotilone isolated from Phellinus linteus was tested and had significant effects on the inhibition of PRIM1 protein expression in ER+ breast cancer cells. In vivo study was performed by administering inotilone (10 mg/kg, twice a week for 6 weeks), which resulted in significantly reduced BT-474-xenografted tumor growth volume compared with control (n =5 per group, *p < 0.05). This study provides evidences for the prognostic effects of PRIM1 with poor overall survival rate in the ER+ patients and will be valuable to test for therapeutic purpose.
Collapse
Affiliation(s)
- Wei-Hwa Lee
- Department of Pathology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.,Department of Pathology, Taipei Medical University-Shuang Ho Hospital, New Taipei City, Taiwan
| | - Li-Ching Chen
- Breast Medical Center, Taipei Medical University Hospital, Taipei, Taiwan.,Taipei Cancer Center, Taipei Medical University, Taipei, Taiwan.,TMU Research Center of Cancer Translational Medicine, Taipei Medical University, Taipei, Taiwan
| | - Chia-Jung Lee
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Chi-Cheng Huang
- Department of Surgery, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.,School of Medicine, College of Medicine, Fu-Jen Catholic University, New Taipei City, Taiwan.,Department of Surgery, Fu-Jen Catholic University Hospital, New Taipei City, Taiwan
| | - Yuan-Soon Ho
- TMU Research Center of Cancer Translational Medicine, Taipei Medical University, Taipei, Taiwan.,Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan.,Department of Laboratory Medicine, Taipei Medical University Hospital, Taipei, Taiwan.,School of Medical Laboratory Science and Biotechnology, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan
| | - Po-Sheng Yang
- Department of Surgery, Mackay Memorial Hospital, Taipei, Taiwan.,Department of Medicine, Mackay Medical College, New Taipei City, Taiwan
| | - Chi-Tang Ho
- Department of Food Science, Rutgers University, New Brunswick, NJ, USA
| | - Hang-Lung Chang
- Department of General Surgery, En Chu Kong Hospital, New Taipei City, Taiwan
| | - I-Hsuan Lin
- TMU Research Center of Cancer Translational Medicine, Taipei Medical University, Taipei, Taiwan
| | - Hui-Wen Chang
- Department of Laboratory Medicine, Taipei Medical University Hospital, Taipei, Taiwan
| | - Yun-Ru Liu
- TMU Research Center of Cancer Translational Medicine, Taipei Medical University, Taipei, Taiwan.,Joint Biobank, Office of Human Research, Taipei Medical University, Taipei, Taiwan
| | - Chih-Hsiung Wu
- Department of Surgery, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.,Department of General Surgery, En Chu Kong Hospital, New Taipei City, Taiwan
| | - Shih-Hsin Tu
- Breast Medical Center, Taipei Medical University Hospital, Taipei, Taiwan.,Taipei Cancer Center, Taipei Medical University, Taipei, Taiwan.,Department of Surgery, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| |
Collapse
|
36
|
Lee JG, Park KR, An JY, Kang JY, Shen H, Wang J, Eom SH. Structural and biochemical insights into inhibition of human primase by citrate. Biochem Biophys Res Commun 2018; 507:383-388. [PMID: 30446220 DOI: 10.1016/j.bbrc.2018.11.047] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 11/08/2018] [Indexed: 10/27/2022]
Abstract
The eukaryotic primase/polymerase complex synthesizes approximately 107 primers, one per Okazaki fragment, during the replication of mammalian chromosomes, which contain 109 base pairs. Primase catalyzes the synthesis of a short RNA segment to a single-stranded DNA template. Primase is important in DNA replication because no known replicative DNA polymerases can initiate the synthesis of a DNA strand without an initial RNA primer. The primase subcomplex is composed of a small catalytic subunit (p49), and a large accessory subunit (p58). Priming mechanisms remain poorly understood, although large numbers of structures of archaeal and eukaryotic p49 and/or p58 as well as structures of bacterial enzymes have been determined. In this study, we determined the structure of human p49 at 2.2 Å resolution with citrate in its inactive forms. Dibasic citrate was bound at the nucleotide triphosphate (NTP) β, γ-phosphate binding site through nine hydrogen bonds. We also measured the dissociation constant of citrate and NTPs. We further demonstrated that the p49 activity is regulated by pH and citrate, which was not previously recognized as a key regulator of DNA replication. We propose that the citrate inhibits the primase and regulates DNA replication at the replication fork.
Collapse
Affiliation(s)
- Jung-Gyu Lee
- School of Life Sciences, Gwangju Institute of Science & Technology, Gwangju, 61005, Republic of Korea; Steitz Center for Structural Biology, Gwangju Institute of Science & Technology, Gwangju, 61005, Republic of Korea
| | - Kyoung Ryoung Park
- School of Life Sciences, Gwangju Institute of Science & Technology, Gwangju, 61005, Republic of Korea; Steitz Center for Structural Biology, Gwangju Institute of Science & Technology, Gwangju, 61005, Republic of Korea
| | - Jun Yop An
- School of Life Sciences, Gwangju Institute of Science & Technology, Gwangju, 61005, Republic of Korea; Steitz Center for Structural Biology, Gwangju Institute of Science & Technology, Gwangju, 61005, Republic of Korea
| | - Jung Youn Kang
- School of Life Sciences, Gwangju Institute of Science & Technology, Gwangju, 61005, Republic of Korea; Steitz Center for Structural Biology, Gwangju Institute of Science & Technology, Gwangju, 61005, Republic of Korea
| | - Haihong Shen
- School of Life Sciences, Gwangju Institute of Science & Technology, Gwangju, 61005, Republic of Korea
| | - Jimin Wang
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, 06520-8114, USA.
| | - Soo Hyun Eom
- School of Life Sciences, Gwangju Institute of Science & Technology, Gwangju, 61005, Republic of Korea; Steitz Center for Structural Biology, Gwangju Institute of Science & Technology, Gwangju, 61005, Republic of Korea; Department of Chemistry, Gwangju Institute of Science & Technology, Gwangju, 61005, Republic of Korea.
| |
Collapse
|
37
|
Teo RD, Rousseau BJG, Smithwick ER, Di Felice R, Beratan DN, Migliore A. Charge Transfer between [4Fe4S] Proteins and DNA Is Unidirectional: Implications for Biomolecular Signaling. Chem 2019; 5:122-37. [PMID: 30714018 DOI: 10.1016/j.chempr.2018.09.026] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Recent experiments suggest that DNA-mediated charge transport might enable signaling between the [4Fe4S] clusters in the C-terminal domains of human DNA primase and polymerase α, as well as the signaling between other replication and repair high-potential [4Fe4S] proteins. Our theoretical study demonstrates that the redox signaling cannot be accomplished exclusively by DNA-mediated charge transport because part of the charge transfer chain has an unfavorable free energy profile. We show that hole or excess electron transfer between a [4Fe4S] cluster and a nucleic acid duplex through a protein medium can occur within microseconds in one direction, while it is kinetically hindered in the opposite direction. We present a set of signaling mechanisms that may occur with the assistance of oxidants or reductants, using the allowed charge transfer processes. These mechanisms would enable the coordinated action of [4Fe4S] proteins on DNA, engaging the [4Fe4S] oxidation state dependence of the protein-DNA binding affinity.
Collapse
|
38
|
Abstract
This chapter focuses on the enzymes and mechanisms involved in lagging-strand DNA replication in eukaryotic cells. Recent structural and biochemical progress with DNA polymerase α-primase (Pol α) provides insights how each of the millions of Okazaki fragments in a mammalian cell is primed by the primase subunit and further extended by its polymerase subunit. Rapid kinetic studies of Okazaki fragment elongation by Pol δ illuminate events when the polymerase encounters the double-stranded RNA-DNA block of the preceding Okazaki fragment. This block acts as a progressive molecular break that provides both time and opportunity for the flap endonuclease 1 (FEN1) to access the nascent flap and cut it. The iterative action of Pol δ and FEN1 is coordinated by the replication clamp PCNA and produces a regulated degradation of the RNA primer, thereby preventing the formation of long-strand displacement flaps. Occasional long flaps are further processed by backup nucleases including Dna2.
Collapse
Affiliation(s)
- Joseph L Stodola
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, Saint Louis, MO, USA
| | - Peter M Burgers
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, Saint Louis, MO, USA.
| |
Collapse
|
39
|
Yan J, Holzer S, Pellegrini L, Bell SD. An archaeal primase functions as a nanoscale caliper to define primer length. Proc Natl Acad Sci U S A 2018; 115:6697-702. [PMID: 29891690 DOI: 10.1073/pnas.1806351115] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
The first phosphodiester linkage made during DNA replication is in the context of a short RNA primer synthesized by the dedicated RNA polymerase, primase. Primase, after synthesizing a defined short oligoribonucleotide, then transfers this primer to a DNA polymerase for extension. The mechanisms by which primer length is constrained remain elusive. Here, we dissect the basis of “counting” by an archaeal primase and propose a caliper-like mechanism to account for length determination. The cellular replicative DNA polymerases cannot initiate DNA synthesis without a priming 3′ OH. During DNA replication, this is supplied in the context of a short RNA primer molecule synthesized by DNA primase. The primase of archaea and eukaryotes, despite having varying subunit compositions, share sequence and structural homology. Intriguingly, archaeal primase has been demonstrated to possess the ability to synthesize DNA de novo, a property shared with the eukaryotic PrimPol enzymes. The dual RNA and DNA synthetic capabilities of the archaeal DNA primase have led to the proposal that there may be a sequential hand-off between these synthetic modes of primase. In the current work, we dissect the functional interplay between DNA and RNA synthetic modes of primase. In addition, we determine the key determinants that govern primer length definition by the archaeal primase. Our results indicate a primer measuring system that functions akin to a caliper.
Collapse
|
40
|
Tsai CL, Tainer JA. Robust Production, Crystallization, Structure Determination, and Analysis of [Fe-S] Proteins: Uncovering Control of Electron Shuttling and Gating in the Respiratory Metabolism of Molybdopterin Guanine Dinucleotide Enzymes. Methods Enzymol 2017; 599:157-196. [PMID: 29746239 DOI: 10.1016/bs.mie.2017.11.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
[Fe-S] clusters are essential cofactors in all domains of life. They play many biological roles due to their unique abilities for electron transfer and conformational control. Yet, producing and analyzing Fe-S proteins can be difficult and even misleading if not done anaerobically. Due to unique redox properties of [Fe-S] clusters and their oxygen sensitivity, they pose multiple challenges and can lose enzymatic activity or cause their component proteins to be structurally disordered due to [Fe-S] cluster oxidation and loss in air. Here we highlight tested protocols and strategies enabling efficient and stable [Fe-S] protein production, purification, crystallization, X-ray diffraction data collection, and structure determination. From multiple high-resolution anaerobic crystal structures, we furthermore analyze exemplary data defining [Fe-S] clusters, substrate entry, and product exit for the functional oxidation states of type II molybdo-bis(molybdopterin guanine dinucleotide) (Mo-bisMGD) enzymes. Notably, these enzymes perform electron shuttling between quinone pools and specific substrates to catalyze respiratory metabolism. The identified structure-activity relationships for this enzyme class have broad implications germane to perchlorate environments on Earth and Mars extending to an alternative mechanism underlying metabolic origins for the evolution of the oxygen atmosphere. Integrated structural analyses of type II Mo-bisMGD enzymes unveil novel distinctive shared molecular mechanisms for dynamic control of substrate entry and product release gated by hydrophobic residues. Collective findings support a prototypic model for type II Mo-bisMGD enzymes including insights for a fundamental molecular mechanistic understanding of selectivity and regulation by a conformationally gated channel with general implications for [Fe-S] cluster respiratory enzymes.
Collapse
Affiliation(s)
- Chi-Lin Tsai
- The University of Texas M. D. Anderson Cancer Center, Houston, TX, United States
| | - John A Tainer
- The University of Texas M. D. Anderson Cancer Center, Houston, TX, United States; Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, United States.
| |
Collapse
|
41
|
Kazlauskas D, Sezonov G, Charpin N, Venclovas Č, Forterre P, Krupovic M. Novel Families of Archaeo-Eukaryotic Primases Associated with Mobile Genetic Elements of Bacteria and Archaea. J Mol Biol 2017; 430:737-750. [PMID: 29198957 PMCID: PMC5862659 DOI: 10.1016/j.jmb.2017.11.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Revised: 11/22/2017] [Accepted: 11/23/2017] [Indexed: 11/15/2022]
Abstract
Cellular organisms in different domains of life employ structurally unrelated, non-homologous DNA primases for synthesis of a primer for DNA replication. Archaea and eukaryotes encode enzymes of the archaeo-eukaryotic primase (AEP) superfamily, whereas bacteria uniformly use primases of the DnaG family. However, AEP genes are widespread in bacterial genomes raising questions regarding their provenance and function. Here, using an archaeal primase–polymerase PolpTN2 encoded by pTN2 plasmid as a seed for sequence similarity searches, we recovered over 800 AEP homologs from bacteria belonging to 12 highly diverse phyla. These sequences formed a supergroup, PrimPol-PV1, and could be classified into five novel AEP families which are characterized by a conserved motif containing an arginine residue likely to be involved in nucleotide binding. Functional assays confirm the essentiality of this motif for catalytic activity of the PolpTN2 primase–polymerase. Further analyses showed that bacterial AEPs display a range of domain organizations and uncovered several candidates for novel families of helicases. Furthermore, sequence and structure comparisons suggest that PriCT-1 and PriCT-2 domains frequently fused to the AEP domains are related to each other as well as to the non-catalytic, large subunit of archaeal and eukaryotic primases, and to the recently discovered PriX subunit of archaeal primases. Finally, genomic neighborhood analysis indicates that the identified AEPs encoded in bacterial genomes are nearly exclusively associated with highly diverse integrated mobile genetic elements, including integrative conjugative plasmids and prophages. Primases of the archaeo-eukaryotic primase (AEP) superfamily are widespread in bacteria. We describe five new AEP families in bacteria belonging to 12 diverse phyla. The new AEP families display a conserved signature motif likely involved in nucleotide binding. The primase domains are fused to diverse functional domains, revealing new families of putative helicases. The novel primases are encoded within highly diverse integrated mobile genetic elements.
Collapse
Affiliation(s)
- Darius Kazlauskas
- Institute of Biotechnology, Vilnius University, Saulėtekio av. 7, Vilnius 10257, Lithuania
| | - Guennadi Sezonov
- Sorbonne Universités, UPMC Université Paris 06, CNRS, UMR 7138 Evolution Paris Seine-Institut de Biologie Paris Seine, Paris 75005, France
| | - Nicole Charpin
- Unité Biologie Moléculaire du Gène chez les Extrêmophiles, Department of Microbiology, Institut Pasteur, 25 rue du Docteur Roux, Paris 75015, France
| | - Česlovas Venclovas
- Institute of Biotechnology, Vilnius University, Saulėtekio av. 7, Vilnius 10257, Lithuania.
| | - Patrick Forterre
- Unité Biologie Moléculaire du Gène chez les Extrêmophiles, Department of Microbiology, Institut Pasteur, 25 rue du Docteur Roux, Paris 75015, France
| | - Mart Krupovic
- Unité Biologie Moléculaire du Gène chez les Extrêmophiles, Department of Microbiology, Institut Pasteur, 25 rue du Docteur Roux, Paris 75015, France.
| |
Collapse
|
42
|
Abstract
Research during the past decade witnessed the discovery of [4Fe-4S] clusters in several members of the eukaryotic DNA replication machinery. The presence of clusters was confirmed by UV-visible absorption, electron paramagnetic resonance spectroscopy, and metal analysis for primase and the B-family DNA polymerases δ and ζ. The crystal structure of primase revealed that the [4Fe-4S] cluster is buried inside the protein and fulfills a structural role. Although [4Fe-4S] clusters are firmly established in the C-terminal domains of catalytic subunits of DNA polymerases δ and ζ, no structures are currently available and their precise roles have not been ascertained. The [4Fe-4S] clusters in the polymerases and primase play a structural role ensuring proper protein folding and stability. In DNA polymerases δ and ζ, they can potentially play regulatory role by sensing hurdles during DNA replication and assisting with DNA polymerase switches by oscillation between oxidized-reduced states.
Collapse
Affiliation(s)
- Andrey G Baranovskiy
- Eppley Institute for Research in Cancer, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, United States
| | | | - Youri I Pavlov
- Eppley Institute for Research in Cancer, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, United States.
| | - Tahir H Tahirov
- Eppley Institute for Research in Cancer, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, United States.
| |
Collapse
|
43
|
Holzer S, Yan J, Kilkenny ML, Bell SD, Pellegrini L. Primer synthesis by a eukaryotic-like archaeal primase is independent of its Fe-S cluster. Nat Commun 2017; 8:1718. [PMID: 29167441 DOI: 10.1038/s41467-017-01707-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Accepted: 10/09/2017] [Indexed: 01/11/2023] Open
Abstract
DNA replication depends on primase, the specialised polymerase responsible for synthesis of the RNA primers that are elongated by the replicative DNA polymerases. In eukaryotic and archaeal replication, primase is a heterodimer of two subunits, PriS and PriL. Recently, a third primase subunit named PriX was identified in the archaeon Sulfolobus solfataricus. PriX is essential for primer synthesis and is structurally related to the Fe–S cluster domain of eukaryotic PriL. Here we show that PriX contains a nucleotide-binding site required for primer synthesis, and demonstrate equivalence of nucleotide-binding residues in PriX with eukaryotic PriL residues that are known to be important for primer synthesis. A primase chimera, where PriX is fused to a truncated version of PriL lacking the Fe–S cluster domain retains wild-type levels of primer synthesis. Our evidence shows that PriX has replaced PriL as the subunit that endows primase with the unique ability to initiate nucleic acid synthesis. Importantly, our findings reveal that the Fe–S cluster is not required for primer synthesis. Primase is the specialised DNA-dependent RNA polymerase responsible for the initiation of DNA synthesis during DNA replication. Here the authors use a structural biology approach to identify the initiation site in the S. solfataricus PriSLX primase and to demonstrate that its Fe-S cluster is dispensable for primer synthesis.
Collapse
|
44
|
Ganduri S, Lue NF. STN1-POLA2 interaction provides a basis for primase-pol α stimulation by human STN1. Nucleic Acids Res 2017; 45:9455-9466. [PMID: 28934486 PMCID: PMC5766158 DOI: 10.1093/nar/gkx621] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Accepted: 07/06/2017] [Indexed: 01/12/2023] Open
Abstract
The CST (CTC1–STN1–TEN1) complex mediates critical functions in maintaining telomere DNA and overcoming genome-wide replication stress. A conserved biochemical function of the CST complex is its primase-Pol α (PP) stimulatory activity. In this report, we demonstrate the ability of purified human STN1 alone to promote PP activity in vitro. We show that this regulation is mediated primarily by the N-terminal OB fold of STN1, but does not require the DNA-binding activity of this domain. Rather, we observed a strong correlation between the PP-stimulatory activity of STN1 variants and their abilities to bind POLA2. Remarkably, the main binding target of STN1 in POLA2 is the latter's central OB fold domain. In the substrate-free structure of PP, this domain is positioned so as to block nucleic acid entry to the Pol α active site. Thus the STN1–POLA2 interaction may promote the necessary conformational change for nucleic acid delivery to Pol α and subsequent DNA synthesis. A disease-causing mutation in human STN1 engenders a selective defect in POLA2-binding and PP stimulation, indicating that these activities are critical for the in vivo function of STN1. Our findings have implications for the molecular mechanisms of PP, STN1 and STN1-related molecular pathology.
Collapse
Affiliation(s)
- Swapna Ganduri
- Department of Microbiology & Immunology, W. R. Hearst Microbiology Research Center, Weill Cornell Medical College, New York, NY 10065, USA
| | - Neal F Lue
- Department of Microbiology & Immunology, W. R. Hearst Microbiology Research Center, Weill Cornell Medical College, New York, NY 10065, USA.,Sandra and Edward Meyer Cancer Center, Weill Cornell Medicine, New York, NY 10065, USA
| |
Collapse
|
45
|
Baranovskiy AG, Babayeva ND, Zhang Y, Blanco L, Pavlov YI, Tahirov TH. Comment on "The [4Fe4S] cluster of human DNA primase functions as a redox switch using DNA charge transport". Science 2017; 357:357/6348/eaan2396. [PMID: 28729484 DOI: 10.1126/science.aan2396] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 06/13/2017] [Indexed: 12/27/2022]
Abstract
O'Brien et al (Research Article, 24 February 2017, eaag1789) proposed a novel mechanism of primase function based on redox activity of the iron-sulfur cluster buried inside the C-terminal domain of the large primase subunit (p58C). Serious problems in the experimental design and data interpretation raise concerns about the validity of the conclusions.
Collapse
Affiliation(s)
- Andrey G Baranovskiy
- Eppley Institute for Research in Cancer and Allied Diseases, Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Nigar D Babayeva
- Eppley Institute for Research in Cancer and Allied Diseases, Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Yinbo Zhang
- Department of Immunology, University of Washington, Seattle WA 98195, USA
| | - Luis Blanco
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Madrid 28049, Spain
| | - Youri I Pavlov
- Eppley Institute for Research in Cancer and Allied Diseases, Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198, USA.,Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA.,Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Tahir H Tahirov
- Eppley Institute for Research in Cancer and Allied Diseases, Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198, USA.
| |
Collapse
|
46
|
O'Brien E, Holt ME, Thompson MK, Salay LE, Ehlinger AC, Chazin WJ, Barton JK. The [4Fe4S] cluster of human DNA primase functions as a redox switch using DNA charge transport. Science 2017; 355:355/6327/eaag1789. [PMID: 28232525 DOI: 10.1126/science.aag1789] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 01/23/2017] [Indexed: 01/05/2023]
Abstract
DNA charge transport chemistry offers a means of long-range, rapid redox signaling. We demonstrate that the [4Fe4S] cluster in human DNA primase can make use of this chemistry to coordinate the first steps of DNA synthesis. Using DNA electrochemistry, we found that a change in oxidation state of the [4Fe4S] cluster acts as a switch for DNA binding. Single-atom mutations that inhibit this charge transfer hinder primase initiation without affecting primase structure or polymerization. Generating a single base mismatch in the growing primer duplex, which attenuates DNA charge transport, inhibits primer truncation. Thus, redox signaling by [4Fe4S] clusters using DNA charge transport regulates primase binding to DNA and illustrates chemistry that may efficiently drive substrate handoff between polymerases during DNA replication.
Collapse
Affiliation(s)
- Elizabeth O'Brien
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Marilyn E Holt
- Departments of Biochemistry and Chemistry, Center for Structural Biology, Vanderbilt University, Nashville, TN 37235, USA
| | - Matthew K Thompson
- Departments of Biochemistry and Chemistry, Center for Structural Biology, Vanderbilt University, Nashville, TN 37235, USA
| | - Lauren E Salay
- Departments of Biochemistry and Chemistry, Center for Structural Biology, Vanderbilt University, Nashville, TN 37235, USA
| | - Aaron C Ehlinger
- Departments of Biochemistry and Chemistry, Center for Structural Biology, Vanderbilt University, Nashville, TN 37235, USA
| | - Walter J Chazin
- Departments of Biochemistry and Chemistry, Center for Structural Biology, Vanderbilt University, Nashville, TN 37235, USA.
| | - Jacqueline K Barton
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
| |
Collapse
|
47
|
Abstract
Replication of DNA in eukaryotes is primarily executed by the combined action of processive DNA polymerases δ and ɛ. These enzymes cannot initiate synthesis of new DNA without the presence of a primer on the template ssDNA. The primers on both the leading and lagging strands are generated by DNA polymerase α-primase (pol-prim). DNA primase is a DNA-dependent RNA polymerase that synthesizes the first ~10 nucleotides and then transfers the substrate to polymerase α to complete primer synthesis. The mechanisms governing the coordination and handoff between primase and polymerase α are largely unknown. Isolated DNA primase contains a [4Fe-4S]2+ cluster that has been shown to serve as a redox switch modulating DNA binding affinity. This discovery suggests a mechanism for modulating the priming activity of primase and handoff to polymerase α. In this chapter, we briefly discuss the current state of knowledge of primase structure and function, including the role of its iron-sulfur cluster. This is followed by providing the methods for expressing, purifying, and biophysically/structurally characterizing primase and its iron-sulfur cluster-containing domain, p58C.
Collapse
Affiliation(s)
- Marilyn E Holt
- Center for Structural Biology, Vanderbilt University, Nashville, TN, United States
| | - Lauren E Salay
- Center for Structural Biology, Vanderbilt University, Nashville, TN, United States
| | - Walter J Chazin
- Center for Structural Biology, Vanderbilt University, Nashville, TN, United States.
| |
Collapse
|
48
|
Baranovskiy AG, Gu J, Babayeva ND, Kurinov I, Pavlov YI, Tahirov TH. Crystal structure of the human Polϵ B-subunit in complex with the C-terminal domain of the catalytic subunit. J Biol Chem 2017; 292:15717-15730. [PMID: 28747437 DOI: 10.1074/jbc.m117.792705] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Revised: 07/21/2017] [Indexed: 12/13/2022] Open
Abstract
The eukaryotic B-family DNA polymerases include four members: Polα, Polδ, Polϵ, and Polζ, which share common architectural features, such as the exonuclease/polymerase and C-terminal domains (CTDs) of catalytic subunits bound to indispensable B-subunits, which serve as scaffolds that mediate interactions with other components of the replication machinery. Crystal structures for the B-subunits of Polα and Polδ/Polζ have been reported: the former within the primosome and separately with CTD and the latter with the N-terminal domain of the C-subunit. Here we present the crystal structure of the human Polϵ B-subunit (p59) in complex with CTD of the catalytic subunit (p261C). The structure revealed a well defined electron density for p261C and the phosphodiesterase and oligonucleotide/oligosaccharide-binding domains of p59. However, electron density was missing for the p59 N-terminal domain and for the linker connecting it to the phosphodiesterase domain. Similar to Polα, p261C of Polϵ contains a three-helix bundle in the middle and zinc-binding modules on each side. Intersubunit interactions involving 11 hydrogen bonds and numerous hydrophobic contacts account for stable complex formation with a buried surface area of 3094 Å2 Comparative structural analysis of p59-p261C with the corresponding Polα complex revealed significant differences between the B-subunits and CTDs, as well as their interaction interfaces. The B-subunit of Polδ/Polζ also substantially differs from B-subunits of either Polα or Polϵ. This work provides a structural basis to explain biochemical and genetic data on the importance of B-subunit integrity in replisome function in vivo.
Collapse
Affiliation(s)
- Andrey G Baranovskiy
- From the Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center and
| | - Jianyou Gu
- From the Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center and
| | - Nigar D Babayeva
- From the Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center and
| | - Igor Kurinov
- the Department of Chemistry and Chemical Biology, Cornell University, Northeastern Collaborative Access Team, Advanced Photon Source, Argonne, Illinois 60439
| | - Youri I Pavlov
- From the Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center and.,the Departments of Biochemistry and Molecular Biology, Pathology and Microbiology, and Genetics and Anatomy, University of Nebraska Medical Center, Omaha, Nebraska 68198 and
| | - Tahir H Tahirov
- From the Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center and
| |
Collapse
|
49
|
Boldinova EO, Wanrooij PH, Shilkin ES, Wanrooij S, Makarova AV. DNA Damage Tolerance by Eukaryotic DNA Polymerase and Primase PrimPol. Int J Mol Sci 2017; 18:E1584. [PMID: 28754021 PMCID: PMC5536071 DOI: 10.3390/ijms18071584] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 07/14/2017] [Accepted: 07/16/2017] [Indexed: 12/31/2022] Open
Abstract
PrimPol is a human deoxyribonucleic acid (DNA) polymerase that also possesses primase activity and is involved in DNA damage tolerance, the prevention of genome instability and mitochondrial DNA maintenance. In this review, we focus on recent advances in biochemical and crystallographic studies of PrimPol, as well as in identification of new protein-protein interaction partners. Furthermore, we discuss the possible functions of PrimPol in both the nucleus and the mitochondria.
Collapse
Affiliation(s)
- Elizaveta O Boldinova
- Institute of Molecular Genetics of Russian Academy of Sciences, Kurchatov sq. 2, 123182 Moscow, Russia.
| | - Paulina H Wanrooij
- Department of Medical Biochemistry and Biophysics, Umeå University, 901 87 Umeå, Sweden.
| | - Evgeniy S Shilkin
- Institute of Molecular Genetics of Russian Academy of Sciences, Kurchatov sq. 2, 123182 Moscow, Russia.
| | - Sjoerd Wanrooij
- Department of Medical Biochemistry and Biophysics, Umeå University, 901 87 Umeå, Sweden.
| | - Alena V Makarova
- Institute of Molecular Genetics of Russian Academy of Sciences, Kurchatov sq. 2, 123182 Moscow, Russia.
| |
Collapse
|
50
|
Abstract
Multiprotein machines drive virtually all primary cellular processes. Modular multidomain proteins are widely distributed within these dynamic complexes because they provide the flexibility needed to remodel structure as well as rapidly assemble and disassemble components of the machinery. Understanding the functional dynamics of modular multidomain proteins is a major challenge confronting structural biology today because their structure is not fixed in time. Small-angle X-ray scattering (SAXS) and nuclear magnetic resonance (NMR) spectroscopy have proven particularly useful for the analysis of the structural dynamics of modular multidomain proteins because they provide highly complementary information for characterizing the architectural landscape accessible to these proteins. SAXS provides a global snapshot of all architectural space sampled by a molecule in solution. Furthermore, SAXS is sensitive to conformational changes, organization and oligomeric states of protein assemblies, and the existence of flexibility between globular domains in multiprotein complexes. The power of NMR to characterize dynamics provides uniquely complementary information to the global snapshot of the architectural ensemble provided by SAXS because it can directly measure domain motion. In particular, NMR parameters can be used to define the diffusion of domains within modular multidomain proteins, connecting the amplitude of interdomain motion to the architectural ensemble derived from SAXS. Our laboratory has been studying the roles of modular multidomain proteins involved in human DNA replication using SAXS and NMR. Here, we present the procedure for acquiring and analyzing SAXS and NMR data, using DNA primase and replication protein A as examples.
Collapse
Affiliation(s)
- Matthew K Thompson
- Departments of Biochemistry and Chemistry, Center for Structural Biology, Vanderbilt University, Nashville, TN, United States
| | - Aaron C Ehlinger
- Departments of Biochemistry and Chemistry, Center for Structural Biology, Vanderbilt University, Nashville, TN, United States
| | - Walter J Chazin
- Departments of Biochemistry and Chemistry, Center for Structural Biology, Vanderbilt University, Nashville, TN, United States.
| |
Collapse
|