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Guo P, Driver D, Zhao Z, Zheng Z, Chan C, Cheng X. Controlling the Revolving and Rotating Motion Direction of Asymmetric Hexameric Nanomotor by Arginine Finger and Channel Chirality. ACS NANO 2019; 13:6207-6223. [PMID: 31067030 PMCID: PMC6595433 DOI: 10.1021/acsnano.8b08849] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Nanomotors in nanotechnology are as important as engines in daily life. Many ATPases are nanoscale biomotors classified into three categories based on the motion mechanisms in transporting substrates: linear, rotating, and the recently discovered revolving motion. Most biomotors adopt a multisubunit ring-shaped structure that hydrolyzes ATP to generate force. How these biomotors control the motion direction and regulate the sequential action of their multiple subunits is intriguing. Many ATPases are hexameric with each monomer containing a conserved arginine finger. This review focuses on recent findings on how the arginine finger controls motion direction and coordinates adjacent subunit interactions in both revolving and rotating biomotors. Mechanisms of intersubunit interactions and sequential movements of individual subunits are evidenced by the asymmetrical appearance of one dimer and four monomers in high-resolution structural complexes. The arginine finger is situated at the interface of two subunits and extends into the ATP binding pocket of the downstream subunit. An arginine finger mutation results in deficiency in ATP binding/hydrolysis, substrate binding, and transport, highlighting the importance of the arginine finger in regulating energy transduction and motor function. Additionally, the roles of channel chirality and channel size are discussed as related to controlling one-way trafficking and differentiating the revolving and rotating mechanisms. Finally, the review concludes by discussing the conformational changes and entropy conversion triggered by ATP binding/hydrolysis, offering a view different from the traditional concept of ATP-mediated mechanochemical energy coupling. The elucidation of the motion mechanism and direction control in ATPases could facilitate nanomotor fabrication in nanotechnology.
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Affiliation(s)
- Peixuan Guo
- Center
for RNA Nanobiotechnology and Nanomedicine, College of Pharmacy
and College of Medicine, Dorothy M. Davis Heart and Lung Research
Institute, Comprehensive Cancer Center and College of Pharmacy, Biophysics
Graduate Program, Translational Data Analytics Institute, The Ohio State University, Columbus, Ohio 43210, United
States
- E-mail:
| | - Dana Driver
- Center
for RNA Nanobiotechnology and Nanomedicine, College of Pharmacy
and College of Medicine, Dorothy M. Davis Heart and Lung Research
Institute, Comprehensive Cancer Center and College of Pharmacy, Biophysics
Graduate Program, Translational Data Analytics Institute, The Ohio State University, Columbus, Ohio 43210, United
States
| | - Zhengyi Zhao
- Center
for RNA Nanobiotechnology and Nanomedicine, College of Pharmacy
and College of Medicine, Dorothy M. Davis Heart and Lung Research
Institute, Comprehensive Cancer Center and College of Pharmacy, Biophysics
Graduate Program, Translational Data Analytics Institute, The Ohio State University, Columbus, Ohio 43210, United
States
| | - Zhen Zheng
- Center
for RNA Nanobiotechnology and Nanomedicine, College of Pharmacy
and College of Medicine, Dorothy M. Davis Heart and Lung Research
Institute, Comprehensive Cancer Center and College of Pharmacy, Biophysics
Graduate Program, Translational Data Analytics Institute, The Ohio State University, Columbus, Ohio 43210, United
States
| | - Chun Chan
- Center
for RNA Nanobiotechnology and Nanomedicine, College of Pharmacy
and College of Medicine, Dorothy M. Davis Heart and Lung Research
Institute, Comprehensive Cancer Center and College of Pharmacy, Biophysics
Graduate Program, Translational Data Analytics Institute, The Ohio State University, Columbus, Ohio 43210, United
States
| | - Xiaolin Cheng
- Center
for RNA Nanobiotechnology and Nanomedicine, College of Pharmacy
and College of Medicine, Dorothy M. Davis Heart and Lung Research
Institute, Comprehensive Cancer Center and College of Pharmacy, Biophysics
Graduate Program, Translational Data Analytics Institute, The Ohio State University, Columbus, Ohio 43210, United
States
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Dai L, Flechsig H, Yu J. Deciphering Intrinsic Inter-subunit Couplings that Lead to Sequential Hydrolysis of F 1-ATPase Ring. Biophys J 2017; 113:1440-1453. [PMID: 28978438 PMCID: PMC5627347 DOI: 10.1016/j.bpj.2017.08.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Revised: 07/31/2017] [Accepted: 08/04/2017] [Indexed: 11/05/2022] Open
Abstract
Rotary sequential hydrolysis of the metabolic machine F1-ATPase is a prominent manifestation of high coordination among multiple chemical sites in ring-shaped molecular machines, and it is also functionally essential for F1 to tightly couple chemical reactions and central γ-shaft rotation. High-speed AFM experiments have identified that sequential hydrolysis is maintained in the F1 stator ring even in the absence of the γ-rotor. To explore the origins of intrinsic sequential performance, we computationally investigated essential inter-subunit couplings on the hexameric ring of mitochondrial and bacterial F1. We first reproduced in stochastic Monte Carlo simulations the experimentally determined sequential hydrolysis schemes by kinetically imposing inter-subunit couplings and following subsequent tri-site ATP hydrolysis cycles on the F1 ring. We found that the key couplings to support the sequential hydrolysis are those that accelerate neighbor-site ADP and Pi release upon a certain ATP binding or hydrolysis reaction. The kinetically identified couplings were then examined in atomistic molecular dynamics simulations at a coarse-grained level to reveal the underlying structural mechanisms. To do that, we enforced targeted conformational changes of ATP binding or hydrolysis to one chemical site on the F1 ring and monitored the ensuing conformational responses of the neighboring sites using structure-based simulations. Notably, we found asymmetrical neighbor-site opening that facilitates ADP release upon enforced ATP binding. We also captured a complete charge-hopping process of the Pi release subsequent to enforced ATP hydrolysis in the neighbor site, confirming recent single-molecule analyses with regard to the role of ATP hydrolysis in F1. Our studies therefore elucidate both the coordinated chemical kinetics and structural dynamics mechanisms underpinning the sequential operation of the F1 ring.
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Affiliation(s)
- Liqiang Dai
- Complex System Research Division, Beijing Computational Science Research Center, Beijing, China
| | - Holger Flechsig
- Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University, Hiroshima, Japan
| | - Jin Yu
- Complex System Research Division, Beijing Computational Science Research Center, Beijing, China.
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Hanhijärvi KJ, Ziedaite G, Bamford DH, Hæggström E, Poranen MM. Single-molecule measurements of viral ssRNA packaging. RNA (NEW YORK, N.Y.) 2017; 23:119-129. [PMID: 27803153 PMCID: PMC5159644 DOI: 10.1261/rna.057471.116] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 10/27/2016] [Indexed: 06/06/2023]
Abstract
Genome packaging of double-stranded RNA (dsRNA) phages has been widely studied using biochemical and molecular biology methods. We adapted the existing in vitro packaging system of one such phage for single-molecule experimentation. To our knowledge, this is the first attempt to study the details of viral RNA packaging using optical tweezers. Pseudomonas phage φ6 is a dsRNA virus with a tripartite genome. Positive-sense (+) single-stranded RNA (ssRNA) genome precursors are packaged into a preformed procapsid (PC), where negative strands are synthesized. We present single-molecule measurements of the viral ssRNA packaging by the φ6 PC. Our data show that packaging proceeds intermittently in slow and fast phases, which likely reflects differences in the unfolding of the RNA secondary structures of the ssRNA being packaged. Although the mean packaging velocity was relatively low (0.07-0.54 nm/sec), packaging could reach 4.62 nm/sec during the fast packaging phase.
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Affiliation(s)
| | - Gabija Ziedaite
- Department of Biosciences, University of Helsinki, Helsinki 00014, Finland
| | - Dennis H Bamford
- Department of Biosciences, University of Helsinki, Helsinki 00014, Finland
- Institute of Biotechnology, University of Helsinki, Helsinki 00014, Finland
| | - Edward Hæggström
- Department of Physics, University of Helsinki, Helsinki 00014, Finland
| | - Minna M Poranen
- Department of Biosciences, University of Helsinki, Helsinki 00014, Finland
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Pi F, Zhao Z, Chelikani V, Yoder K, Kvaratskhelia M, Guo P. Development of Potent Antiviral Drugs Inspired by Viral Hexameric DNA-Packaging Motors with Revolving Mechanism. J Virol 2016; 90:8036-46. [PMID: 27356896 PMCID: PMC5008075 DOI: 10.1128/jvi.00508-16] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The intracellular parasitic nature of viruses and the emergence of antiviral drug resistance necessitate the development of new potent antiviral drugs. Recently, a method for developing potent inhibitory drugs by targeting biological machines with high stoichiometry and a sequential-action mechanism was described. Inspired by this finding, we reviewed the development of antiviral drugs targeting viral DNA-packaging motors. Inhibiting multisubunit targets with sequential actions resembles breaking one bulb in a series of Christmas lights, which turns off the entire string. Indeed, studies on viral DNA packaging might lead to the development of new antiviral drugs. Recent elucidation of the mechanism of the viral double-stranded DNA (dsDNA)-packaging motor with sequential one-way revolving motion will promote the development of potent antiviral drugs with high specificity and efficiency. Traditionally, biomotors have been classified into two categories: linear and rotation motors. Recently discovered was a third type of biomotor, including the viral DNA-packaging motor, beside the bacterial DNA translocases, that uses a revolving mechanism without rotation. By analogy, rotation resembles the Earth's rotation on its own axis, while revolving resembles the Earth's revolving around the Sun (see animations at http://rnanano.osu.edu/movie.html). Herein, we review the structures of viral dsDNA-packaging motors, the stoichiometries of motor components, and the motion mechanisms of the motors. All viral dsDNA-packaging motors, including those of dsDNA/dsRNA bacteriophages, adenoviruses, poxviruses, herpesviruses, mimiviruses, megaviruses, pandoraviruses, and pithoviruses, contain a high-stoichiometry machine composed of multiple components that work cooperatively and sequentially. Thus, it is an ideal target for potent drug development based on the power function of the stoichiometries of target complexes that work sequentially.
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Affiliation(s)
- Fengmei Pi
- Division of Pharmaceutics and Pharmaceutical Chemistry, College of Pharmacy, Department of Physiology and Cell Biology, College of Medicine, and the Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio, USA
| | - Zhengyi Zhao
- Division of Pharmaceutics and Pharmaceutical Chemistry, College of Pharmacy, Department of Physiology and Cell Biology, College of Medicine, and the Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio, USA
| | - Venkata Chelikani
- Faculty of Agriculture and Life Sciences, Lincoln University, Lincoln, Canterbury, New Zealand
| | - Kristine Yoder
- Department of Molecular Virology, Immunology, and Medical Genetics, College of Medicine, The Ohio State University, Columbus, Ohio, USA
| | - Mamuka Kvaratskhelia
- Division of Pharmaceutics and Pharmaceutical Chemistry, College of Pharmacy, Department of Physiology and Cell Biology, College of Medicine, and the Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio, USA
| | - Peixuan Guo
- Division of Pharmaceutics and Pharmaceutical Chemistry, College of Pharmacy, Department of Physiology and Cell Biology, College of Medicine, and the Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio, USA
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Shu D, Pi F, Wang C, Zhang P, Guo P. New approach to develop ultra-high inhibitory drug using the power function of the stoichiometry of the targeted nanomachine or biocomplex. Nanomedicine (Lond) 2016; 10:1881-97. [PMID: 26139124 DOI: 10.2217/nnm.15.37] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
AIMS To find methods for potent drug development by targeting to biocomplex with high copy number. METHODS Phi29 DNA packaging motor components with different stoichiometries were used as model to assay virion assembly with Yang Hui's Triangle [Formula: see text], where Z = stoichiometry, M = drugged subunits per biocomplex, p and q are the fraction of drugged and undrugged subunits in the population. RESULTS Inhibition efficiency follows a power function. When number of drugged subunits to block the function of the complex K = 1, the uninhibited biocomplex equals q(z), demonstrating the multiplicative effect of stoichiometry on inhibition with stoichiometry 1000 > 6 > 1. Complete inhibition of virus replication was found when Z = 6. CONCLUSION Drug inhibition potency depends on the stoichiometry of the targeted components of the biocomplex or nanomachine. The inhibition effect follows a power function of the stoichiometry of the target biocomplex.
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Affiliation(s)
- Dan Shu
- Department of Pharmaceutical Sciences, Markey Cancer Center, University of Kentucky, Lexington, KY 40536, USA
| | - Fengmei Pi
- Department of Pharmaceutical Sciences, Markey Cancer Center, University of Kentucky, Lexington, KY 40536, USA
| | - Chi Wang
- Department of Biostatistics & Nanobiotechnology Center, University of Kentucky, Lexington, KY 40536, USA
| | - Peng Zhang
- Department of Surgery, University of Michigan Health System, Ann Arbor, MI 48109, USA
| | - Peixuan Guo
- Department of Pharmaceutical Sciences, Markey Cancer Center, University of Kentucky, Lexington, KY 40536, USA
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Morra R, Fessl T, Wang Y, Mancini EJ, Tuma R. Biophysical Characterization of Chromatin Remodeling Protein CHD4. Methods Mol Biol 2016; 1431:175-193. [PMID: 27283310 DOI: 10.1007/978-1-4939-3631-1_14] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Chromatin-remodeling ATPases modulate histones-DNA interactions within nucleosomes and regulate transcription. At the heart of remodeling, ATPase is a helicase-like motor flanked by a variety of conserved targeting domains. CHD4 is the core subunit of the nucleosome remodeling and deacetylase complex NuRD and harbors tandem plant homeo finger (tPHD) and chromo (tCHD) domains. We describe a multifaceted approach to link the domain structure with function, using quantitative assays for DNA and histone binding, ATPase activity, shape reconstruction from solution scattering data, and single molecule translocation assays. These approaches are complementary to high-resolution structure determination.
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Affiliation(s)
- Rosa Morra
- Faculty of Life Sciences, Manchester Institute of Biotechnology, University of Manchester, Manchester, UK
| | - Tomas Fessl
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Yuchong Wang
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | | | - Roman Tuma
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK.
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Pi F, Vieweger M, Zhao Z, Wang S, Guo P. Discovery of a new method for potent drug development using power function of stoichiometry of homomeric biocomplexes or biological nanomotors. Expert Opin Drug Deliv 2015; 13:23-36. [PMID: 26307193 DOI: 10.1517/17425247.2015.1082544] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
INTRODUCTION Multidrug resistance and the appearance of incurable diseases inspire the quest for potent therapeutics. AREAS COVERED We review a new methodology in designing potent drugs by targeting multi-subunit homomeric biological motors, machines or complexes with Z > 1 and K = 1, where Z is the stoichiometry of the target, and K is the number of drugged subunits required to block the function of the complex. The condition is similar to a series electrical circuit of Christmas decorations: failure of one light bulb causes the entire lighting system to lose power. In most multi-subunit, homomeric biological systems, a sequential coordination or cooperative action mechanism is utilized, thus K equals 1. Drug inhibition depends on the ratio of drugged to non-drugged complexes. When K = 1, and Z > 1, the inhibition effect follows a power law with respect to Z, leading to enhanced drug potency. The hypothesis that the potency of drug inhibition depends on the stoichiometry of the targeted biological complexes was recently quantified by Yang-Hui's Triangle (or binomial distribution), and proved using a highly sensitive in vitro phi29 viral DNA packaging system. Examples of targeting homomeric bio-complexes with high stoichiometry for potent drug discovery are discussed. EXPERT OPINION Biomotors with multiple subunits are widespread in viruses, bacteria and cells, making this approach generally applicable in the development of inhibition drugs with high efficiency.
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Affiliation(s)
- Fengmei Pi
- a 1 University of Kentucky, Nanobiotechnology Center , Lexington, KY 40536, USA.,b 2 University of Kentucky, Markey Cancer Center , Lexington, KY 40536, USA.,c 3 University of Kentucky, Department of Pharmaceutical Sciences , 789 S. Limestone Street, Room # 576, Lexington, KY 40536, USA +1 859 218 0128 ; +1 859 257 1307 ;
| | - Mario Vieweger
- a 1 University of Kentucky, Nanobiotechnology Center , Lexington, KY 40536, USA.,b 2 University of Kentucky, Markey Cancer Center , Lexington, KY 40536, USA.,c 3 University of Kentucky, Department of Pharmaceutical Sciences , 789 S. Limestone Street, Room # 576, Lexington, KY 40536, USA +1 859 218 0128 ; +1 859 257 1307 ;
| | - Zhengyi Zhao
- a 1 University of Kentucky, Nanobiotechnology Center , Lexington, KY 40536, USA.,b 2 University of Kentucky, Markey Cancer Center , Lexington, KY 40536, USA.,c 3 University of Kentucky, Department of Pharmaceutical Sciences , 789 S. Limestone Street, Room # 576, Lexington, KY 40536, USA +1 859 218 0128 ; +1 859 257 1307 ;
| | - Shaoying Wang
- a 1 University of Kentucky, Nanobiotechnology Center , Lexington, KY 40536, USA.,b 2 University of Kentucky, Markey Cancer Center , Lexington, KY 40536, USA.,c 3 University of Kentucky, Department of Pharmaceutical Sciences , 789 S. Limestone Street, Room # 576, Lexington, KY 40536, USA +1 859 218 0128 ; +1 859 257 1307 ;
| | - Peixuan Guo
- a 1 University of Kentucky, Nanobiotechnology Center , Lexington, KY 40536, USA.,b 2 University of Kentucky, Markey Cancer Center , Lexington, KY 40536, USA.,c 3 University of Kentucky, Department of Pharmaceutical Sciences , 789 S. Limestone Street, Room # 576, Lexington, KY 40536, USA +1 859 218 0128 ; +1 859 257 1307 ;
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8
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Happonen LJ, Erdmann S, Garrett RA, Butcher SJ. Adenosine triphosphatases of thermophilic archaeal double-stranded DNA viruses. Cell Biosci 2014; 4:37. [PMID: 25105011 PMCID: PMC4124505 DOI: 10.1186/2045-3701-4-37] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Accepted: 06/13/2014] [Indexed: 12/02/2022] Open
Abstract
Adenosine triphosphatases (ATPases) of double-stranded (ds) DNA archaeal viruses are structurally related to the AAA+ hexameric helicases and translocases. These ATPases have been implicated in viral life cycle functions such as DNA entry into the host, and viral genome packaging into preformed procapsids. We summarize bioinformatical analyses of a wide range of archaeal ATPases, and review the biochemical and structural properties of those archaeal ATPases that have measurable ATPase activity. We discuss their potential roles in genome delivery into the host, virus assembly and genome packaging in comparison to hexameric helicases and packaging motors from bacteriophages.
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Affiliation(s)
- Lotta J Happonen
- Department of Clinical Sciences, Division of Infection Medicine, Lund University, SE-221 84 Lund, Sweden
| | - Susanne Erdmann
- Archaea Centre, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen N, Denmark
| | - Roger A Garrett
- Archaea Centre, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen N, Denmark
| | - Sarah J Butcher
- Institute of Biotechnology, University of Helsinki, (Viikinkaari 1), P.O. Box 65, FI-00014 Helsinki, Finland
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Abstract
All life on earth can be naturally classified into cellular life forms and virus-like selfish elements, the latter being fully dependent on the former for their reproduction. Cells are reproducers that not only replicate their genome but also reproduce the cellular organization that depends on semipermeable, energy-transforming membranes and cannot be recovered from the genome alone, under the famous dictum of Rudolf Virchow, Omnis cellula e cellula. In contrast, simple selfish elements are replicators that can complete their life cycles within the host cell starting from genomic RNA or DNA alone. The origin of the cellular organization is the central and perhaps the hardest problem of evolutionary biology. I argue that the origin of cells can be understood only in conjunction with the origin and evolution of selfish genetic elements. A scenario of precellular evolution is presented that involves cohesion of the genomes of the emerging cellular life forms from primordial pools of small genetic elements that eventually segregated into hosts and parasites. I further present a model of the coevolution of primordial membranes and membrane proteins, discuss protocellular and non-cellular models of early evolution, and examine the habitats on the primordial earth that could have been conducive to precellular evolution and the origin of cells.
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Affiliation(s)
- Eugene V Koonin
- National Center for Biotechnology Information, National Library of Medicine, National Institute of Health, Bethesda, MD, 20894, USA,
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10
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Yu J. Coordination and control inside simple biomolecular machines. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 805:353-84. [PMID: 24446369 DOI: 10.1007/978-3-319-02970-2_15] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Biomolecular machines can achieve physiological functions precisely and efficiently, though they always operate under fluctuations and noises. We review two types of simple machinery that we have recently studied. The machinery can be regarded as molecular motors. They transform chemical free energy from NTP hydrolysis to mechanical work. One type belongs to small monomeric helicases that move directionally along single-stranded nucleic acid, and may further unwind the duplex part for gene replication or repair. The other type belongs to ring-shaped NTPase motors that also move or transport nucleic acid or protein substrate in a directional manner, such as for genome packaging or protein degradation. The central issue in this review is on how the machinery coordinates essential degrees of freedom during the mechanochemical coupling process. Further concerns include how the coordination and control are manifested in experiments, and how they can be captured well in modeling and computational research. We employed atomistic molecular dynamics simulations, coarse-grained analyses, and stochastic modeling techniques to examine the molecular machines at multiple resolutions and timescales. Detailed descriptions on how the protein interacts with its substrate at interface, as well as how multiple protein subunits are coordinated are summarized.
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Affiliation(s)
- Jin Yu
- Beijing Computational Science Research Center, No 3 Heqing Road, Haidian District, Beijing, 100084, China,
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11
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Sharma A, Leach RN, Gell C, Zhang N, Burrows PC, Shepherd DA, Wigneshweraraj S, Smith DA, Zhang X, Buck M, Stockley PG, Tuma R. Domain movements of the enhancer-dependent sigma factor drive DNA delivery into the RNA polymerase active site: insights from single molecule studies. Nucleic Acids Res 2014; 42:5177-90. [PMID: 24553251 PMCID: PMC4005640 DOI: 10.1093/nar/gku146] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Recognition of bacterial promoters is regulated by two distinct classes of sequence-specific sigma factors, σ70 or σ54, that differ both in their primary sequence and in the requirement of the latter for activation via enhancer-bound upstream activators. The σ54 version controls gene expression in response to stress, often mediating pathogenicity. Its activator proteins are members of the AAA+ superfamily and use adenosine triphosphate (ATP) hydrolysis to remodel initially auto-inhibited holoenzyme promoter complexes. We have mapped this remodeling using single-molecule fluorescence spectroscopy. Initial remodeling is nucleotide-independent and driven by binding both ssDNA during promoter melting and activator. However, DNA loading into the RNA polymerase active site depends on co-operative ATP hydrolysis by the activator. Although the coupled promoter recognition and melting steps may be conserved between σ70 and σ54, the domain movements of the latter have evolved to require an activator ATPase.
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Affiliation(s)
- Amit Sharma
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK, Department of Life Sciences, Sir Alexander Fleming Building, Imperial College, London SW72AZ, UK and School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK
| | - Robert N. Leach
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK, Department of Life Sciences, Sir Alexander Fleming Building, Imperial College, London SW72AZ, UK and School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK
| | - Christopher Gell
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK, Department of Life Sciences, Sir Alexander Fleming Building, Imperial College, London SW72AZ, UK and School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK
| | - Nan Zhang
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK, Department of Life Sciences, Sir Alexander Fleming Building, Imperial College, London SW72AZ, UK and School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK
| | - Patricia C. Burrows
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK, Department of Life Sciences, Sir Alexander Fleming Building, Imperial College, London SW72AZ, UK and School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK
| | - Dale A. Shepherd
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK, Department of Life Sciences, Sir Alexander Fleming Building, Imperial College, London SW72AZ, UK and School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK
| | - Sivaramesh Wigneshweraraj
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK, Department of Life Sciences, Sir Alexander Fleming Building, Imperial College, London SW72AZ, UK and School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK
| | - David Alastair Smith
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK, Department of Life Sciences, Sir Alexander Fleming Building, Imperial College, London SW72AZ, UK and School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK
| | - Xiaodong Zhang
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK, Department of Life Sciences, Sir Alexander Fleming Building, Imperial College, London SW72AZ, UK and School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK
| | - Martin Buck
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK, Department of Life Sciences, Sir Alexander Fleming Building, Imperial College, London SW72AZ, UK and School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK
| | - Peter G. Stockley
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK, Department of Life Sciences, Sir Alexander Fleming Building, Imperial College, London SW72AZ, UK and School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK
- *To whom correspondence should be addressed. Tel: +44 1133 433092; Fax: +44 1133 437897;
| | - Roman Tuma
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK, Department of Life Sciences, Sir Alexander Fleming Building, Imperial College, London SW72AZ, UK and School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK
- Correspondence may also be addressed to Roman Tuma. Tel: +44 1133 433080; Fax: +44 1133 437897;
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12
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Cornish-Bowden A. Understanding allosteric and cooperative interactions in enzymes. FEBS J 2013; 281:621-32. [DOI: 10.1111/febs.12469] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Revised: 07/24/2013] [Accepted: 07/30/2013] [Indexed: 01/25/2023]
Affiliation(s)
- Athel Cornish-Bowden
- Unité de Bioénergétique et Ingénierie des Protéines; Institut de Microbiologie de la Méditerranée; Centre National de la Recherche Scientifique and Aix-Marseille Université; France
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13
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El Omari K, Meier C, Kainov D, Sutton G, Grimes JM, Poranen MM, Bamford DH, Tuma R, Stuart DI, Mancini EJ. Tracking in atomic detail the functional specializations in viral RecA helicases that occur during evolution. Nucleic Acids Res 2013; 41:9396-410. [PMID: 23939620 PMCID: PMC3814363 DOI: 10.1093/nar/gkt713] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Many complex viruses package their genomes into empty protein shells and bacteriophages of the Cystoviridae family provide some of the simplest models for this. The cystoviral hexameric NTPase, P4, uses chemical energy to translocate single-stranded RNA genomic precursors into the procapsid. We previously dissected the mechanism of RNA translocation for one such phage, ɸ12, and have now investigated three further highly divergent, cystoviral P4 NTPases (from ɸ6, ɸ8 and ɸ13). High-resolution crystal structures of the set of P4s allow a structure-based phylogenetic analysis, which reveals that these proteins form a distinct subfamily of the RecA-type ATPases. Although the proteins share a common catalytic core, they have different specificities and control mechanisms, which we map onto divergent N- and C-terminal domains. Thus, the RNA loading and tight coupling of NTPase activity with RNA translocation in ɸ8 P4 is due to a remarkable C-terminal structure, which wraps right around the outside of the molecule to insert into the central hole where RNA binds to coupled L1 and L2 loops, whereas in ɸ12 P4, a C-terminal residue, serine 282, forms a specific hydrogen bond to the N7 of purines ring to confer purine specificity for the ɸ12 enzyme.
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Affiliation(s)
- Kamel El Omari
- Division of Structural Biology, The Wellcome Trust Centre for Human Genetics, University of Oxford, Headington, Oxford OX3 7BN, UK, Institute for Molecular Medicine Finland (FIMM), University of Helsinki, 00290 Helsinki, Finland, Department of Environmental Research, Siauliai University, Vilniaus gatvė 88, 76285 Siauliai, Lithuania, Diamond Light Source Limited, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, UK, Department of Biosciences, University of Helsinki, Biocenter 2, PO Box 56, 00014 Helsinki, Finland, Institute of Biotechnology, University of Helsinki, Biocenter 2, PO Box 56, 00014 Helsinki, Finland and Astbury Centre for Structural Molecular Biology and School of Cellular and Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
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14
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Abstract
P4 proteins are hexameric RNA packaging ATPases of dsRNA bacteriophages of the Cystoviridae family. P4 hexamers are integral part of the inner polymerase core and play several essential roles in the virus replication cycle. P4 proteins are structurally related to the hexameric helicases and translocases of superfamily 4 (SF4) and other RecA-like ATPases. Recombinant P4 proteins retain their 5' to 3' helicase and translocase activity in vitro and thus serve as a model system for studying the mechanism of action of hexameric ring helicases and RNA translocation. This review summarizes the different roles that P4 proteins play during virus assembly, genome packaging, and transcription. Structural and mechanistic details of P4 action are laid out to and subsequently compared with those of the related hexameric helicases and other packaging motors.
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Affiliation(s)
- Erika J Mancini
- Wellcome Trust Centre for Human Genetics, Oxford University, Oxford, OX3 7BN, UK.
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15
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Morais MC. The dsDNA Packaging Motor in Bacteriophage ø29. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 726:511-47. [DOI: 10.1007/978-1-4614-0980-9_23] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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16
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Schwartz C, Fang H, Huang L, Guo P. Sequential action of ATPase, ATP, ADP, Pi and dsDNA in procapsid-free system to enlighten mechanism in viral dsDNA packaging. Nucleic Acids Res 2011; 40:2577-86. [PMID: 22110031 PMCID: PMC3315319 DOI: 10.1093/nar/gkr841] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Many cells and double-stranded DNA (dsDNA) viruses contain an AAA(+) ATPase that assembles into oligomers, often hexamers, with a central channel. The dsDNA packaging motor of bacteriophage phi29 also contains an ATPase to translocate dsDNA through a dodecameric channel. The motor ATPase has been investigated substantially in the context of the entire procapsid. Here, we report the sequential action between the ATPase and additional motor components. It is suggested that the contact of ATPase to ATP resulted in its conformational change to a higher binding affinity toward dsDNA. It was found that ATP hydrolysis led to the departure of dsDNA from the ATPase/dsDNA complex, an action that is speculated to push dsDNA to pass the connector channel. Our results suggest that dsDNA packaging goes through a combined effort of both the gp16 ATPase for pushing and the channel as a one-way valve to control the dsDNA translocation direction. Many packaging models have previously been proposed, and the packaging mechanism has been contingent upon the number of nucleotides packaged per ATP relative to the 10.5 bp per helical turn for B-type dsDNA. Both 2 and 2.5 bp per ATP have been used to argue for four, five or six discrete steps of dsDNA translocation. Combination of the two distinct roles of gp16 and connector renews the perception of previous dsDNA packaging energy calculations and provides insight into the discrepancy between 2 and 2.5 bp per ATP.
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Affiliation(s)
- Chad Schwartz
- The School of Environmental, Energy, Biological, and Medical Engineering (SEEBME), Nanobiomedical Center, University of Cincinnati, Cincinnati, OH 45267, USA
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17
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The kinesin-13 MCAK has an unconventional ATPase cycle adapted for microtubule depolymerization. EMBO J 2011; 30:3928-39. [PMID: 21873978 PMCID: PMC3209780 DOI: 10.1038/emboj.2011.290] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2011] [Accepted: 07/18/2011] [Indexed: 01/11/2023] Open
Abstract
Most kinesins move directionally along microtubules, but MCAK instead depolymerizes them. This study analyses the ATPase cycle of MCAK, identifying unusual kinetic features that fit with its unconventional activity. Unlike other kinesins, members of the kinesin-13 subfamily do not move directionally along microtubules but, instead, depolymerize them. To understand how kinesins with structurally similar motor domains can have such dissimilar functions, we elucidated the ATP turnover cycle of the kinesin-13, MCAK. In contrast to translocating kinesins, ATP cleavage, rather than product release, is the rate-limiting step for ATP turnover by MCAK; unpolymerized tubulin and microtubules accelerate this step. Further, microtubule ends fully activate the ATPase by accelerating the exchange of ADP for ATP. This tuning of the cycle adapts MCAK for its depolymerization activity: lattice-stimulated ATP cleavage drives MCAK into a weakly bound nucleotide state that reaches microtubule ends by diffusion, and end-specific acceleration of nucleotide exchange drives MCAK into a strongly bound state that promotes depolymerization. This altered cycle accounts well for the different mechanical behaviour of this kinesin, which depolymerizes microtubules from their ends, compared to translocating kinesins that walk along microtubules. Thus, the kinesin motor domain is a nucleotide-dependent engine that can be differentially tuned for transport or depolymerization functions.
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18
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Affiliation(s)
- Roman Tuma
- The Astbury Centre for Structural Molecular Biology, Institute of Cellular and Molecular Biology, University of Leeds Leeds UK
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19
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Yu J, Moffitt J, Hetherington CL, Bustamante C, Oster G. Mechanochemistry of a Viral DNA Packaging Motor. J Mol Biol 2010; 400:186-203. [PMID: 20452360 DOI: 10.1016/j.jmb.2010.05.002] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2010] [Revised: 04/30/2010] [Accepted: 05/02/2010] [Indexed: 01/29/2023]
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20
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Enemark EJ, Joshua-Tor L. On helicases and other motor proteins. Curr Opin Struct Biol 2008; 18:243-57. [PMID: 18329872 DOI: 10.1016/j.sbi.2008.01.007] [Citation(s) in RCA: 160] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2007] [Revised: 01/17/2008] [Accepted: 01/21/2008] [Indexed: 01/30/2023]
Abstract
Helicases are molecular machines that utilize energy derived from ATP hydrolysis to move along nucleic acids and to separate base-paired nucleotides. The movement of the helicase can also be described as a stationary helicase that pumps nucleic acid. Recent structural data for the hexameric E1 helicase of papillomavirus in complex with single-stranded DNA and MgADP has provided a detailed atomic and mechanistic picture of its ATP-driven DNA translocation. The structural and mechanistic features of this helicase are compared with the hexameric helicase prototypes T7gp4 and SV40 T-antigen. The ATP-binding site architectures of these proteins are structurally similar to the sites of other prototypical ATP-driven motors such as F1-ATPase, suggesting related roles for the individual site residues in the ATPase activity.
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Affiliation(s)
- Eric J Enemark
- W.M. Keck Structural Biology Laboratory, Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY 11724, United States
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21
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Kainov DE, Mancini EJ, Telenius J, Lísal J, Grimes JM, Bamford DH, Stuart DI, Tuma R. Structural basis of mechanochemical coupling in a hexameric molecular motor. J Biol Chem 2007; 283:3607-3617. [PMID: 18057007 DOI: 10.1074/jbc.m706366200] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The P4 protein of bacteriophage phi12 is a hexameric molecular motor closely related to superfamily 4 helicases. P4 converts chemical energy from ATP hydrolysis into mechanical work, to translocate single-stranded RNA into a viral capsid. The molecular basis of mechanochemical coupling, i.e. how small approximately 1 A changes in the ATP-binding site are amplified into nanometer scale motion along the nucleic acid, is not understood at the atomic level. Here we study in atomic detail the mechanochemical coupling using structural and biochemical analyses of P4 mutants. We show that a conserved region, consisting of superfamily 4 helicase motifs H3 and H4 and loop L2, constitutes the moving lever of the motor. The lever tip encompasses an RNA-binding site that moves along the mechanical reaction coordinate. The lever is flanked by gamma-phosphate sensors (Asn-234 and Ser-252) that report the nucleotide state of neighboring subunits and control the lever position. Insertion of an arginine finger (Arg-279) into the neighboring catalytic site is concomitant with lever movement and commences ATP hydrolysis. This ensures cooperative sequential hydrolysis that is tightly coupled to mechanical motion. Given the structural conservation, the mutated residues may play similar roles in other hexameric helicases and related molecular motors.
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Affiliation(s)
- Denis E Kainov
- Institute of Biotechnology and Department of Biological and Environmental Sciences, University of Helsinki, Viikki Biocenter P. O. Box 65, Helsinki FIN-00014, Finland
| | - Erika J Mancini
- Division of Structural Biology, The Henry Wellcome Building for Genomic Medicine, Oxford University, Roosevelt Drive, Oxford OX3 7BN, United Kingdom
| | - Jelena Telenius
- Institute of Biotechnology and Department of Biological and Environmental Sciences, University of Helsinki, Viikki Biocenter P. O. Box 65, Helsinki FIN-00014, Finland
| | - Jiří Lísal
- Institute of Biotechnology and Department of Biological and Environmental Sciences, University of Helsinki, Viikki Biocenter P. O. Box 65, Helsinki FIN-00014, Finland
| | - Jonathan M Grimes
- Division of Structural Biology, The Henry Wellcome Building for Genomic Medicine, Oxford University, Roosevelt Drive, Oxford OX3 7BN, United Kingdom
| | - Dennis H Bamford
- Institute of Biotechnology and Department of Biological and Environmental Sciences, University of Helsinki, Viikki Biocenter P. O. Box 65, Helsinki FIN-00014, Finland
| | - David I Stuart
- Division of Structural Biology, The Henry Wellcome Building for Genomic Medicine, Oxford University, Roosevelt Drive, Oxford OX3 7BN, United Kingdom.
| | - Roman Tuma
- Institute of Biotechnology and Department of Biological and Environmental Sciences, University of Helsinki, Viikki Biocenter P. O. Box 65, Helsinki FIN-00014, Finland.
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22
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Mancini EJ, Assenberg R, Verma A, Walter TS, Tuma R, Grimes JM, Owens RJ, Stuart DI. Structure of the Murray Valley encephalitis virus RNA helicase at 1.9 Angstrom resolution. Protein Sci 2007; 16:2294-300. [PMID: 17893366 PMCID: PMC2204129 DOI: 10.1110/ps.072843107] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Murray Valley encephalitis virus (MVEV), a mosquito-borne flavivirus endemic to Australia, is closely related to Japanese encephalitis virus and West Nile virus. Nonstructural protein 3 (NS3) is a multifunctional enzyme with serine protease and DEXH/D-box helicase domains, whose activity is central to flavivirus replication and is therefore a possible target for anti-flaviviral compounds. Cloning, purification, and crystal structure determination to 1.9 Angstrom resolution of the NS3 helicase of MVEV and characterization of its enzymatic activity is reported. Comparison with the structures of helicases from related viruses supports a possible mechanism of ATP hydrolysis-driven strand separation.
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Affiliation(s)
- Erika J Mancini
- Division of Structural Biology and Oxford Protein Production Facility, The Henry Wellcome Building for Genomic Medicine, Oxford University, Oxford, UK
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23
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Jäälinoja HT, Huiskonen JT, Butcher SJ. Electron cryomicroscopy comparison of the architectures of the enveloped bacteriophages phi6 and phi8. Structure 2007; 15:157-67. [PMID: 17292834 DOI: 10.1016/j.str.2006.12.004] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2006] [Revised: 12/21/2006] [Accepted: 12/22/2006] [Indexed: 11/30/2022]
Abstract
The enveloped dsRNA bacteriophages phi6 and phi8 are the two most distantly related members of the Cystoviridae family. Their structure and function are similar to that of the Reoviridae but their assembly can be conveniently studied in vitro. Electron cryomicroscopy and three-dimensional icosahedral reconstruction were used to determine the structures of the phi6 virion (14 A resolution), phi8 virion (18 A resolution), and phi8 core (8.5 A resolution). Spikes protrude 2 nm from the membrane bilayer in phi6 and 7 nm in phi8. In the phi6 nucleocapsid, 600 copies of P8 and 72 copies of P4 interact with the membrane, whereas in phi8 it is only P4 and 60 copies of a minor protein. The major polymerase complex protein P1 forms a dodecahedral shell from 60 asymmetric dimers in both viruses, but the alpha-helical fold has apparently diverged. These structural differences reflect the different host ranges and entry and assembly mechanisms of the two viruses.
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Affiliation(s)
- Harri T Jäälinoja
- Centre of Excellence in Virus Research and Institute of Biotechnology, University of Helsinki, FI-00014 Helsinki, Finland
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24
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Skordalakes E, Berger JM. Structural insights into RNA-dependent ring closure and ATPase activation by the Rho termination factor. Cell 2006; 127:553-64. [PMID: 17081977 DOI: 10.1016/j.cell.2006.08.051] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2006] [Revised: 07/25/2006] [Accepted: 08/25/2006] [Indexed: 11/16/2022]
Abstract
Hexameric helicases and translocases are required for numerous essential nucleic-acid transactions. To better understand the mechanisms by which these enzymes recognize target substrates and use nucleotide hydrolysis to power molecular movement, we have determined the structure of the Rho transcription termination factor, a hexameric RNA/DNA helicase, with single-stranded RNA bound to the motor domains of the protein. The structure reveals a closed-ring "trimer of dimers" conformation for the hexamer that contains an unanticipated arrangement of conserved loops required for nucleic-acid translocation. RNA extends across a shallow intersubunit channel formed by conserved amino acids required for RNA-stimulated ATP hydrolysis and translocation and directly contacts a conserved lysine, just upstream of the catalytic GKT triad, in the phosphate-binding (P loop) motif of the ATP-binding pocket. The structure explains the molecular effects of numerous mutations and provides new insights into the links between substrate recognition, ATP turnover, and coordinated strand movement.
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Affiliation(s)
- Emmanuel Skordalakes
- Department of Molecular and Cell Biology, University of California, Berkeley, 327B Hildebrand Hall #3206, Berkeley, CA 94720, USA
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25
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Massey TH, Mercogliano CP, Yates J, Sherratt DJ, Löwe J. Double-stranded DNA translocation: structure and mechanism of hexameric FtsK. Mol Cell 2006; 23:457-69. [PMID: 16916635 DOI: 10.1016/j.molcel.2006.06.019] [Citation(s) in RCA: 190] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2005] [Revised: 05/15/2006] [Accepted: 06/13/2006] [Indexed: 11/21/2022]
Abstract
FtsK is a DNA translocase that coordinates chromosome segregation and cell division in bacteria. In addition to its role as activator of XerCD site-specific recombination, FtsK can translocate double-stranded DNA (dsDNA) rapidly and directionally and reverse direction. We present crystal structures of the FtsK motor domain monomer, showing that it has a RecA-like core, the FtsK hexamer, and also showing that it is a ring with a large central annulus and a dodecamer consisting of two hexamers, head to head. Electron microscopy (EM) demonstrates the DNA-dependent existence of hexamers in solution and shows that duplex DNA passes through the middle of each ring. Comparison of FtsK monomer structures from two different crystal forms highlights a conformational change that we propose is the structural basis for a rotary inchworm mechanism of DNA translocation.
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Affiliation(s)
- Thomas H Massey
- Division of Molecular Genetics, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom
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26
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Sikora B, Eoff RL, Matson SW, Raney KD. DNA unwinding by Escherichia coli DNA helicase I (TraI) provides evidence for a processive monomeric molecular motor. J Biol Chem 2006; 281:36110-6. [PMID: 16984922 DOI: 10.1074/jbc.m604412200] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The F plasmid TraI protein (DNA helicase I) plays an essential role in conjugative DNA transfer as both a transesterase and a helicase. Previous work has shown that the 192-kDa TraI protein is a highly processive helicase, catalytically separating >850 bp under steady-state conditions. In this report, we examine the kinetic mechanism describing DNA unwinding of TraI. The kinetic step size of TraI was measured under both single turnover and pre-steady-state conditions. The resulting kinetic step-size estimate was approximately 6-8 bp step(-1). TraI can separate double-stranded DNA at a rate of approximately 1100 bp s(-1), similar to the measured unwinding rate of the RecBCD helicase, and appears to dissociate very slowly from the 3' terminus following translocation and strand-separation events. Analyses of pre-steady-state burst amplitudes indicate that TraI can function as a monomer, similar to the bacteriophage T4 helicase, Dda. However, unlike Dda, TraI is a highly processive monomeric helicase, making it unique among the DNA helicases characterized thus far.
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Affiliation(s)
- Bartek Sikora
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205, USA
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27
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Lísal J, Kainov DE, Lam TT, Emmett MR, Wei H, Gottlieb P, Marshall AG, Tuma R. Interaction of packaging motor with the polymerase complex of dsRNA bacteriophage. Virology 2006; 351:73-9. [PMID: 16643976 DOI: 10.1016/j.virol.2006.03.025] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2006] [Revised: 02/15/2006] [Accepted: 03/12/2006] [Indexed: 11/29/2022]
Abstract
Many viruses employ molecular motors to package their genomes into preformed empty capsids (procapsids). In dsRNA bacteriophages the packaging motor is a hexameric ATPase P4, which is an integral part of the multisubunit procapsid. Structural and biochemical studies revealed a plausible RNA-translocation mechanism for the isolated hexamer. However, little is known about the structure and regulation of the hexamer within the procapsid. Here we use hydrogen-deuterium exchange and mass spectrometry to delineate the interactions of the P4 hexamer with the bacteriophage phi12 procapsid. P4 associates with the procapsid via its C-terminal face. The interactions also stabilize subunit interfaces within the hexamer. The conformation of the virus-bound hexamer is more stable than the hexamer in solution, which is prone to spontaneous ring openings. We propose that the stabilization within the viral capsid increases the packaging processivity and confers selectivity during RNA loading.
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Affiliation(s)
- Jirí Lísal
- Institute of Biotechnology and Department of Biological and Environmental Sciences, University of Helsinki, Viikinkaari 1 PL 65, 00014 Helsinki, Finland
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