1
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Schmidt T, Dabrowska A, Waldron JA, Hodge K, Koulouras G, Gabrielsen M, Munro J, Tack DC, Harris G, McGhee E, Scott D, Carlin L, Huang D, Le Quesne J, Zanivan S, Wilczynska A, Bushell M. eIF4A1-dependent mRNAs employ purine-rich 5'UTR sequences to activate localised eIF4A1-unwinding through eIF4A1-multimerisation to facilitate translation. Nucleic Acids Res 2023; 51:1859-1879. [PMID: 36727461 PMCID: PMC9976904 DOI: 10.1093/nar/gkad030] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 12/20/2022] [Accepted: 01/11/2023] [Indexed: 02/03/2023] Open
Abstract
Altered eIF4A1 activity promotes translation of highly structured, eIF4A1-dependent oncogene mRNAs at root of oncogenic translational programmes. It remains unclear how these mRNAs recruit and activate eIF4A1 unwinding specifically to facilitate their preferential translation. Here, we show that single-stranded RNA sequence motifs specifically activate eIF4A1 unwinding allowing local RNA structural rearrangement and translation of eIF4A1-dependent mRNAs in cells. Our data demonstrate that eIF4A1-dependent mRNAs contain AG-rich motifs within their 5'UTR which specifically activate eIF4A1 unwinding of local RNA structure to facilitate translation. This mode of eIF4A1 regulation is used by mRNAs encoding components of mTORC-signalling and cell cycle progression, and renders these mRNAs particularly sensitive to eIF4A1-inhibition. Mechanistically, we show that binding of eIF4A1 to AG-rich sequences leads to multimerization of eIF4A1 with eIF4A1 subunits performing distinct enzymatic activities. Our structural data suggest that RNA-binding of multimeric eIF4A1 induces conformational changes in the RNA resulting in an optimal positioning of eIF4A1 proximal to the RNA duplex enabling efficient unwinding. Our data proposes a model in which AG-motifs in the 5'UTR of eIF4A1-dependent mRNAs specifically activate eIF4A1, enabling assembly of the helicase-competent multimeric eIF4A1 complex, and positioning these complexes proximal to stable localised RNA structure allowing ribosomal subunit scanning.
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Affiliation(s)
- Tobias Schmidt
- Cancer Research UK Beatson Institute, Garscube Estate, Switchback Road, Glasgow G61 1BD, UK
| | - Adrianna Dabrowska
- Cancer Research UK Beatson Institute, Garscube Estate, Switchback Road, Glasgow G61 1BD, UK
- School of Cancer Sciences, University of Glasgow, Garscube Estate, Switchback Road, Glasgow G61 1QH, UK
- Department of Urology, University of California, San Francisco, CA 94158, USA
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Joseph A Waldron
- Cancer Research UK Beatson Institute, Garscube Estate, Switchback Road, Glasgow G61 1BD, UK
| | - Kelly Hodge
- Cancer Research UK Beatson Institute, Garscube Estate, Switchback Road, Glasgow G61 1BD, UK
| | - Grigorios Koulouras
- Cancer Research UK Beatson Institute, Garscube Estate, Switchback Road, Glasgow G61 1BD, UK
| | - Mads Gabrielsen
- MVLS Structural Biology and Biophysical Characterisation Facility, University of Glasgow, University Avenue, Glasgow G12 8QQ, UK
| | - June Munro
- Cancer Research UK Beatson Institute, Garscube Estate, Switchback Road, Glasgow G61 1BD, UK
| | - David C Tack
- Spectrum Health Office of Research and Education, Spectrum Health System, 15 Michigan Street NE, Grand Rapids, MI 49503, USA
| | - Gemma Harris
- Research Complex at Harwell, Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0FA, UK
| | - Ewan McGhee
- Cancer Research UK Beatson Institute, Garscube Estate, Switchback Road, Glasgow G61 1BD, UK
| | - David Scott
- Research Complex at Harwell, Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0FA, UK
- ISIS Spallation Neutron and Muon Source, Rutherford Appleton Laboratory, Harwell Campus, DidcotOX11 0QX, UK
- School of Biosciences, University of Nottingham, Sutton Bonington Campus, Sutton Bonington LE12 5RD, UK
| | - Leo M Carlin
- Cancer Research UK Beatson Institute, Garscube Estate, Switchback Road, Glasgow G61 1BD, UK
- School of Cancer Sciences, University of Glasgow, Garscube Estate, Switchback Road, Glasgow G61 1QH, UK
| | - Danny Huang
- Cancer Research UK Beatson Institute, Garscube Estate, Switchback Road, Glasgow G61 1BD, UK
- School of Cancer Sciences, University of Glasgow, Garscube Estate, Switchback Road, Glasgow G61 1QH, UK
| | - John Le Quesne
- Cancer Research UK Beatson Institute, Garscube Estate, Switchback Road, Glasgow G61 1BD, UK
- School of Cancer Sciences, University of Glasgow, Garscube Estate, Switchback Road, Glasgow G61 1QH, UK
| | - Sara Zanivan
- Cancer Research UK Beatson Institute, Garscube Estate, Switchback Road, Glasgow G61 1BD, UK
- School of Cancer Sciences, University of Glasgow, Garscube Estate, Switchback Road, Glasgow G61 1QH, UK
| | - Ania Wilczynska
- Cancer Research UK Beatson Institute, Garscube Estate, Switchback Road, Glasgow G61 1BD, UK
- School of Cancer Sciences, University of Glasgow, Garscube Estate, Switchback Road, Glasgow G61 1QH, UK
| | - Martin Bushell
- Cancer Research UK Beatson Institute, Garscube Estate, Switchback Road, Glasgow G61 1BD, UK
- School of Cancer Sciences, University of Glasgow, Garscube Estate, Switchback Road, Glasgow G61 1QH, UK
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2
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Lin M, Cui W, Tian H, Zhang Y, Chen C, Yang X, Chi H, Mu Z, Chen C, Wang Z, Ji X, Yang H, Lin Z. Structural Basis of Zika Virus Helicase in RNA Unwinding and ATP Hydrolysis. ACS Infect Dis 2022; 8:150-158. [PMID: 34904824 DOI: 10.1021/acsinfecdis.1c00455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The flavivirus nonstructural protein 3 helicase (NS3hel) is a multifunctional domain protein that is associated with DNA/RNA helicase, nucleoside triphosphatase (NTPase), and RNA 5'-triphosphatase (RTPase) activities. As an NTPase-dependent superfamily 2 (SF2) member, NS3hel employs an NTP-driven motor force to unwind double-stranded RNA while translocating along single-stranded RNA and is extensively involved in the viral replication process. Although the structures of SF2 helicases are widely investigated as promising drug targets, the mechanism of energy transduction between NTP hydrolysis and the RNA binding sites in ZIKV NS3hel remains elusive. Here, we report the crystal structure of ZIKV NS3hel in complex with its natural substrates ATP-Mn2+ and ssRNA. Distinct from other members of the Flavivirus genus, ssRNA binding to ZIKV NS3hel induces relocation of the active water molecules and ATP-associated metal ions in the NTP hydrolysis active site, which promotes the hydrolysis of ATP and the production of AMP. Our findings highlight the importance of the allosteric role of ssRNA on the modulation of ATP hydrolysis and energy utilization.
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Affiliation(s)
- Mengmeng Lin
- School of Life Sciences, Tianjin University, Tianjin 300072, China
- Shanghai Institute for Advanced Immunochemical Studies and School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
- Shanghai Clinical Research and Trial Center, Shanghai 201210, China
| | - Wen Cui
- School of Life Sciences, Tianjin University, Tianjin 300072, China
- Institute of Life Sciences, Chongqing Medical University, Chongqing 400016, China
| | - Hongliang Tian
- School of Life Sciences, Tianjin University, Tianjin 300072, China
| | - Yan Zhang
- School of Life Sciences, Tianjin University, Tianjin 300072, China
| | - Chen Chen
- School of Life Sciences, Tianjin University, Tianjin 300072, China
| | - Xiaoyun Yang
- School of Life Sciences, Tianjin University, Tianjin 300072, China
| | - Heng Chi
- School of Life Sciences, Tianjin University, Tianjin 300072, China
| | - Zhongyu Mu
- School of Life Sciences, Tianjin University, Tianjin 300072, China
| | - Cheng Chen
- School of Life Sciences, Tianjin University, Tianjin 300072, China
| | - Zefang Wang
- School of Life Sciences, Tianjin University, Tianjin 300072, China
- Tianjin International Joint Academy of Biotechnology and Medicine, Tianjin 300457, China
| | - Xiaoyun Ji
- The State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, Jiangsu 210023, China
| | - Haitao Yang
- School of Life Sciences, Tianjin University, Tianjin 300072, China
- Shanghai Institute for Advanced Immunochemical Studies and School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
- Tianjin International Joint Academy of Biotechnology and Medicine, Tianjin 300457, China
- Shanghai Clinical Research and Trial Center, Shanghai 201210, China
| | - Zhi Lin
- School of Life Sciences, Tianjin University, Tianjin 300072, China
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3
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Donsbach P, Klostermeier D. Regulation of RNA helicase activity: principles and examples. Biol Chem 2021; 402:529-559. [PMID: 33583161 DOI: 10.1515/hsz-2020-0362] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 01/29/2021] [Indexed: 12/16/2022]
Abstract
RNA helicases are a ubiquitous class of enzymes involved in virtually all processes of RNA metabolism, from transcription, mRNA splicing and export, mRNA translation and RNA transport to RNA degradation. Although ATP-dependent unwinding of RNA duplexes is their hallmark reaction, not all helicases catalyze unwinding in vitro, and some in vivo functions do not depend on duplex unwinding. RNA helicases are divided into different families that share a common helicase core with a set of helicase signature motives. The core provides the active site for ATP hydrolysis, a binding site for non-sequence-specific interaction with RNA, and in many cases a basal unwinding activity. Its activity is often regulated by flanking domains, by interaction partners, or by self-association. In this review, we summarize the regulatory mechanisms that modulate the activities of the helicase core. Case studies on selected helicases with functions in translation, splicing, and RNA sensing illustrate the various modes and layers of regulation in time and space that harness the helicase core for a wide spectrum of cellular tasks.
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Affiliation(s)
- Pascal Donsbach
- Institute for Physical Chemistry, University of Münster, Corrensstrasse 30, D-48149Münster, Germany
| | - Dagmar Klostermeier
- Institute for Physical Chemistry, University of Münster, Corrensstrasse 30, D-48149Münster, Germany
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4
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Donsbach P, Yee BA, Sanchez-Hevia D, Berenguer J, Aigner S, Yeo GW, Klostermeier D. The Thermus thermophilus DEAD-box protein Hera is a general RNA binding protein and plays a key role in tRNA metabolism. RNA (NEW YORK, N.Y.) 2020; 26:1557-1574. [PMID: 32669294 PMCID: PMC7566566 DOI: 10.1261/rna.075580.120] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 07/05/2020] [Indexed: 06/11/2023]
Abstract
RNA helicases catalyze the ATP-dependent destabilization of RNA duplexes. DEAD-box helicases share a helicase core that mediates ATP binding and hydrolysis, RNA binding and unwinding. Most members of this family contain domains flanking the core that can confer RNA substrate specificity and guide the helicase to a specific RNA. However, the in vivo RNA substrates of most helicases are currently not defined. The DEAD-box helicase Hera from Thermus thermophilus contains a helicase core, followed by a dimerization domain and an RNA binding domain that folds into an RNA recognition motif (RRM). The RRM mediates high affinity binding to an RNA hairpin, and an adjacent duplex is then unwound by the helicase core. Hera is a cold-shock protein, and has been suggested to act as an RNA chaperone under cold-shock conditions. Using crosslinking immunoprecipitation of Hera/RNA complexes and sequencing, we show that Hera binds to a large fraction of T. thermophilus RNAs under normal-growth and cold-shock conditions without a strong sequence preference, in agreement with a structure-specific recognition of RNAs and a general function in RNA metabolism. Under cold-shock conditions, Hera is recruited to RNAs with high propensities to form stable secondary structures. We show that selected RNAs identified, including a set of tRNAs, bind to Hera in vitro, and activate the Hera helicase core. Gene ontology analysis reveals an enrichment of genes related to translation, including mRNAs of ribosomal proteins, tRNAs, tRNA ligases, and tRNA-modifying enzymes, consistent with a key role of Hera in ribosome and tRNA metabolism.
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Affiliation(s)
- Pascal Donsbach
- University of Muenster, Institute for Physical Chemistry, 48149 Muenster, Germany
| | - Brian A Yee
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California 92093, USA
- Stem Cell Program, University of California San Diego, La Jolla, California 92093, USA
- Institute for Genomic Medicine, University of California San Diego, La Jolla, California 92093, USA
| | - Dione Sanchez-Hevia
- Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid, Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain
| | - José Berenguer
- Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid, Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain
| | - Stefan Aigner
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California 92093, USA
- Stem Cell Program, University of California San Diego, La Jolla, California 92093, USA
- Institute for Genomic Medicine, University of California San Diego, La Jolla, California 92093, USA
| | - Gene W Yeo
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California 92093, USA
- Stem Cell Program, University of California San Diego, La Jolla, California 92093, USA
- Institute for Genomic Medicine, University of California San Diego, La Jolla, California 92093, USA
| | - Dagmar Klostermeier
- University of Muenster, Institute for Physical Chemistry, 48149 Muenster, Germany
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5
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Xu L, Wang L, Peng J, Li F, Wu L, Zhang B, Lv M, Zhang J, Gong Q, Zhang R, Zuo X, Zhang Z, Wu J, Tang Y, Shi Y. Insights into the Structure of Dimeric RNA Helicase CsdA and Indispensable Role of Its C-Terminal Regions. Structure 2017; 25:1795-1808.e5. [PMID: 29107486 DOI: 10.1016/j.str.2017.09.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 08/21/2017] [Accepted: 09/20/2017] [Indexed: 02/06/2023]
Abstract
CsdA has been proposed to be essential for the biogenesis of ribosome and gene regulation after cold shock. However, the structure of CsdA and the function of its long C-terminal regions are still unclear. Here, we solved all of the domain structures of CsdA and found two previously uncharacterized auxiliary domains: a dimerization domain (DD) and an RNA-binding domain (RBD). Small-angle X-ray scattering experiments helped to track the conformational flexibilities of the helicase core domains and C-terminal regions. Biochemical assays revealed that DD is indispensable for stabilizing the CsdA dimeric structure. We also demonstrate for the first time that CsdA functions as a stable dimer at low temperature. The C-terminal regions are critical for RNA binding and efficient enzymatic activities. CsdA_RBD could specifically bind to the regions with a preference for single-stranded G-rich RNA, which may help to bring the helicase core to unwind the adjacent duplex.
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Affiliation(s)
- Ling Xu
- Hefei National Laboratory for Physical Science at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Lijun Wang
- Hefei National Laboratory for Physical Science at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Junhui Peng
- Hefei National Laboratory for Physical Science at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Fudong Li
- Hefei National Laboratory for Physical Science at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Lijie Wu
- National Center for Protein Science Shanghai, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Beibei Zhang
- Hefei National Laboratory for Physical Science at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Mengqi Lv
- Hefei National Laboratory for Physical Science at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Jiahai Zhang
- Hefei National Laboratory for Physical Science at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Qingguo Gong
- Hefei National Laboratory for Physical Science at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Rongguang Zhang
- National Center for Protein Science Shanghai, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China; National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Xiaobing Zuo
- X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60349, USA
| | - Zhiyong Zhang
- Hefei National Laboratory for Physical Science at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Jihui Wu
- Hefei National Laboratory for Physical Science at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Yajun Tang
- Hefei National Laboratory for Physical Science at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China.
| | - Yunyu Shi
- Hefei National Laboratory for Physical Science at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China.
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6
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Tauchert MJ, Fourmann JB, Christian H, Lührmann R, Ficner R. Structural and functional analysis of the RNA helicase Prp43 from the thermophilic eukaryote Chaetomium thermophilum. Acta Crystallogr F Struct Biol Commun 2016; 72:112-20. [PMID: 26841761 PMCID: PMC4741191 DOI: 10.1107/s2053230x15024498] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 12/20/2015] [Indexed: 02/03/2023] Open
Abstract
RNA helicases are indispensable for all organisms in each domain of life and have implications in numerous cellular processes. The DEAH-box RNA helicase Prp43 is involved in pre-mRNA splicing as well as rRNA maturation. Here, the crystal structure of Chaetomium thermophilum Prp43 at 2.9 Å resolution is revealed. Furthermore, it is demonstrated that Prp43 from C. thermophilum is capable of functionally replacing its orthologue from Saccharomyces cerevisiae in spliceosomal disassembly assays.
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Affiliation(s)
- Marcel J. Tauchert
- Department of Molecular Structural Biology, Institute for Microbiology and Genetics, GZMB, Georg-August-Universität Göttingen, Justus-von-Liebig Weg 11, 37077 Göttingen, Germany
| | - Jean-Baptiste Fourmann
- Department of Cellular Biochemistry, Max Planck Institute of Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Henning Christian
- Department of Molecular Structural Biology, Institute for Microbiology and Genetics, GZMB, Georg-August-Universität Göttingen, Justus-von-Liebig Weg 11, 37077 Göttingen, Germany
| | - Reinhard Lührmann
- Department of Cellular Biochemistry, Max Planck Institute of Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Ralf Ficner
- Department of Molecular Structural Biology, Institute for Microbiology and Genetics, GZMB, Georg-August-Universität Göttingen, Justus-von-Liebig Weg 11, 37077 Göttingen, Germany
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7
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Ding H, Guo M, Vidhyasagar V, Talwar T, Wu Y. The Q Motif Is Involved in DNA Binding but Not ATP Binding in ChlR1 Helicase. PLoS One 2015; 10:e0140755. [PMID: 26474416 PMCID: PMC4608764 DOI: 10.1371/journal.pone.0140755] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Accepted: 09/30/2015] [Indexed: 01/08/2023] Open
Abstract
Helicases are molecular motors that couple the energy of ATP hydrolysis to the unwinding of structured DNA or RNA and chromatin remodeling. The conversion of energy derived from ATP hydrolysis into unwinding and remodeling is coordinated by seven sequence motifs (I, Ia, II, III, IV, V, and VI). The Q motif, consisting of nine amino acids (GFXXPXPIQ) with an invariant glutamine (Q) residue, has been identified in some, but not all helicases. Compared to the seven well-recognized conserved helicase motifs, the role of the Q motif is less acknowledged. Mutations in the human ChlR1 (DDX11) gene are associated with a unique genetic disorder known as Warsaw Breakage Syndrome, which is characterized by cellular defects in genome maintenance. To examine the roles of the Q motif in ChlR1 helicase, we performed site directed mutagenesis of glutamine to alanine at residue 23 in the Q motif of ChlR1. ChlR1 recombinant protein was overexpressed and purified from HEK293T cells. ChlR1-Q23A mutant abolished the helicase activity of ChlR1 and displayed reduced DNA binding ability. The mutant showed impaired ATPase activity but normal ATP binding. A thermal shift assay revealed that ChlR1-Q23A has a melting point value similar to ChlR1-WT. Partial proteolysis mapping demonstrated that ChlR1-WT and Q23A have a similar globular structure, although some subtle conformational differences in these two proteins are evident. Finally, we found ChlR1 exists and functions as a monomer in solution, which is different from FANCJ, in which the Q motif is involved in protein dimerization. Taken together, our results suggest that the Q motif is involved in DNA binding but not ATP binding in ChlR1 helicase.
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Affiliation(s)
- Hao Ding
- Department of Biochemistry, University of Saskatchewan, Health Sciences Building, 107 Wiggins Road, Saskatoon, Saskatchewan, Canada
| | - Manhong Guo
- Department of Biochemistry, University of Saskatchewan, Health Sciences Building, 107 Wiggins Road, Saskatoon, Saskatchewan, Canada
| | - Venkatasubramanian Vidhyasagar
- Department of Biochemistry, University of Saskatchewan, Health Sciences Building, 107 Wiggins Road, Saskatoon, Saskatchewan, Canada
| | - Tanu Talwar
- Department of Biochemistry, University of Saskatchewan, Health Sciences Building, 107 Wiggins Road, Saskatoon, Saskatchewan, Canada
| | - Yuliang Wu
- Department of Biochemistry, University of Saskatchewan, Health Sciences Building, 107 Wiggins Road, Saskatoon, Saskatchewan, Canada
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8
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Putnam AA, Gao Z, Liu F, Jia H, Yang Q, Jankowsky E. Division of Labor in an Oligomer of the DEAD-Box RNA Helicase Ded1p. Mol Cell 2015. [PMID: 26212457 DOI: 10.1016/j.molcel.2015.06.030] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Most aspects of RNA metabolism involve DEAD-box RNA helicases, enzymes that bind and remodel RNA and RNA-protein complexes in an ATP-dependent manner. Here we show that the DEAD-box helicase Ded1p oligomerizes in the cell and in vitro, and unwinds RNA as a trimer. Two protomers bind the single-stranded region of RNA substrates and load a third protomer to the duplex, which then separates the strands. ATP utilization differs between the strand-separating protomer and those bound to the single-stranded region. Binding of the eukaryotic initiation factor 4G to Ded1p interferes with oligomerization and thereby modulates unwinding activity and RNA affinity of the helicase. Our data reveal a strict division of labor between the Ded1p protomers in the oligomer. This mode of oligomerization fundamentally differs from other helicases. Oligomerization represents a previously unappreciated level of regulation for DEAD-box helicase activities.
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Affiliation(s)
- Andrea A Putnam
- Center for RNA Molecular Biology and Department of Biochemistry, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA
| | - Zhaofeng Gao
- Center for RNA Molecular Biology and Department of Biochemistry, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA
| | - Fei Liu
- Center for RNA Molecular Biology and Department of Biochemistry, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA; College of Veterinary Medicine, Nanjing Agricultural University, Number 1 Weigang, Nanjing 210095, P.R. China
| | - Huijue Jia
- Center for RNA Molecular Biology and Department of Biochemistry, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA; BGI Shenzen, Beishan Industrial Zone, Yantian District, Shenzhen 518083, P.R. China
| | - Quansheng Yang
- Center for RNA Molecular Biology and Department of Biochemistry, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA; McArdle Laboratory of Cancer Research, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53726, USA
| | - Eckhard Jankowsky
- Center for RNA Molecular Biology and Department of Biochemistry, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA.
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9
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Samatanga B, Klostermeier D. DEAD-box RNA helicase domains exhibit a continuum between complete functional independence and high thermodynamic coupling in nucleotide and RNA duplex recognition. Nucleic Acids Res 2014; 42:10644-54. [PMID: 25123660 PMCID: PMC4176333 DOI: 10.1093/nar/gku747] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
DEAD-box helicases catalyze the non-processive unwinding of double-stranded RNA (dsRNA) at the expense of adenosine triphosphate (ATP) hydrolysis. Nucleotide and RNA binding and unwinding are mediated by the RecA domains of the helicase core, but their cooperation in these processes remains poorly understood. We therefore investigated dsRNA and nucleotide binding by the helicase cores and the isolated N- and C-terminal RecA domains (RecA_N, RecA_C) of the DEAD-box proteins Hera and YxiN by steady-state and time-resolved fluorescence methods. Both helicases bind nucleotides predominantly via RecA_N, in agreement with previous studies on Mss116, and with a universal, modular function of RecA_N in nucleotide recognition. In contrast, dsRNA recognition is different: Hera interacts with dsRNA in the absence of nucleotide, involving both RecA domains, whereas for YxiN neither RecA_N nor RecA_C binds dsRNA, and the complete core only interacts with dsRNA after nucleotide has been bound. DEAD-box proteins thus cover a continuum from complete functional independence of their domains, exemplified by Mss116, to various degrees of inter-domain cooperation in dsRNA binding. The different degrees of domain communication and of thermodynamic linkage between dsRNA and nucleotide binding have important implications on the mechanism of dsRNA unwinding, and may help direct RNA helicases to their respective cellular processes.
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Affiliation(s)
- Brighton Samatanga
- Institute for Physical Chemistry, University of Muenster, Correnstrasse 30, 48149 Muenster, Germany
| | - Dagmar Klostermeier
- Institute for Physical Chemistry, University of Muenster, Correnstrasse 30, 48149 Muenster, Germany
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10
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Möhlmann S, Mathew R, Neumann P, Schmitt A, Lührmann R, Ficner R. Structural and functional analysis of the human spliceosomal DEAD-box helicase Prp28. ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2014; 70:1622-30. [PMID: 24914973 PMCID: PMC4051504 DOI: 10.1107/s1399004714006439] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Accepted: 03/23/2014] [Indexed: 11/10/2022]
Abstract
The DEAD-box protein Prp28 is essential for pre-mRNA splicing as it plays a key role in the formation of an active spliceosome. Prp28 participates in the release of the U1 snRNP from the 5'-splice site during association of the U5·U4/U6 tri-snRNP, which is a crucial step in the transition from a pre-catalytic spliceosome to an activated spliceosome. Here, it is demonstrated that the purified helicase domain of human Prp28 (hPrp28ΔN) binds ADP, whereas binding of ATP and ATPase activity could not be detected. ATP binding could not be observed for purified full-length hPrp28 either, but within an assembled spliceosomal complex hPrp28 gains ATP-binding activity. In order to understand the structural basis for the ATP-binding deficiency of isolated hPrp28, the crystal structure of hPrp28ΔN was determined at 2.0 Å resolution. In the crystal the helicase domain adopts a wide-open conformation, as the two RecA-like domains are extraordinarily displaced from the productive ATPase conformation. Binding of ATP is hindered by a closed conformation of the P-loop, which occupies the space required for the γ-phosphate of ATP.
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Affiliation(s)
- Sina Möhlmann
- Molecular Structural Biology, Georg-August-University Göttingen, Justus-von-Liebig Weg 11, 37077 Göttingen, Germany
| | - Rebecca Mathew
- Cellular Biochemistry, Max-Planck-Institute for Biophysical Chemistry, Am Fassberg, 37077 Göttingen, Germany
| | - Piotr Neumann
- Molecular Structural Biology, Georg-August-University Göttingen, Justus-von-Liebig Weg 11, 37077 Göttingen, Germany
| | - Andreas Schmitt
- Molecular Structural Biology, Georg-August-University Göttingen, Justus-von-Liebig Weg 11, 37077 Göttingen, Germany
| | - Reinhard Lührmann
- Cellular Biochemistry, Max-Planck-Institute for Biophysical Chemistry, Am Fassberg, 37077 Göttingen, Germany
| | - Ralf Ficner
- Molecular Structural Biology, Georg-August-University Göttingen, Justus-von-Liebig Weg 11, 37077 Göttingen, Germany
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11
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Abstract
Superfamily 2 helicase proteins are ubiquitous in RNA biology and have an extraordinarily broad set of functional roles. Central among these roles are the promotion of rearrangements of structured RNAs and the remodeling of ribonucleoprotein complexes (RNPs), allowing formation of native RNA structure or progression through a functional cycle of structures. Although all superfamily 2 helicases share a conserved helicase core, they are divided evolutionarily into several families, and it is principally proteins from three families, the DEAD-box, DEAH/RHA, and Ski2-like families, that function to manipulate structured RNAs and RNPs. Strikingly, there are emerging differences in the mechanisms of these proteins, both between families and within the largest family (DEAD-box), and these differences appear to be tuned to their RNA or RNP substrates and their specific roles. This review outlines basic mechanistic features of the three families and surveys individual proteins and the current understanding of their biological substrates and mechanisms.
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Affiliation(s)
- Inga Jarmoskaite
- Department of Molecular Biosciences and the Institute for Cellular and Molecular Biology, University of Texas, Austin, Texas 78712; ,
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12
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Modular peptide binding: From a comparison of natural binders to designed armadillo repeat proteins. J Struct Biol 2014; 185:147-62. [DOI: 10.1016/j.jsb.2013.07.012] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2013] [Revised: 07/26/2013] [Accepted: 07/27/2013] [Indexed: 11/23/2022]
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13
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Mallam AL, Sidote DJ, Lambowitz AM. Molecular insights into RNA and DNA helicase evolution from the determinants of specificity for a DEAD-box RNA helicase. eLife 2014; 3:e04630. [PMID: 25497230 PMCID: PMC4383044 DOI: 10.7554/elife.04630] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Accepted: 12/10/2014] [Indexed: 01/07/2023] Open
Abstract
How different helicase families with a conserved catalytic 'helicase core' evolved to function on varied RNA and DNA substrates by diverse mechanisms remains unclear. In this study, we used Mss116, a yeast DEAD-box protein that utilizes ATP to locally unwind dsRNA, to investigate helicase specificity and mechanism. Our results define the molecular basis for the substrate specificity of a DEAD-box protein. Additionally, they show that Mss116 has ambiguous substrate-binding properties and interacts with all four NTPs and both RNA and DNA. The efficiency of unwinding correlates with the stability of the 'closed-state' helicase core, a complex with nucleotide and nucleic acid that forms as duplexes are unwound. Crystal structures reveal that core stability is modulated by family-specific interactions that favor certain substrates. This suggests how present-day helicases diversified from an ancestral core with broad specificity by retaining core closure as a common catalytic mechanism while optimizing substrate-binding interactions for different cellular functions.
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Affiliation(s)
- Anna L Mallam
- Institute for Cellular
and Molecular Biology, University of Texas at
Austin, Austin, United States,Department of Molecular
Biosciences, University of Texas at
Austin, Austin, United States
| | - David J Sidote
- Institute for Cellular
and Molecular Biology, University of Texas at
Austin, Austin, United States,Department of Molecular
Biosciences, University of Texas at
Austin, Austin, United States
| | - Alan M Lambowitz
- Institute for Cellular
and Molecular Biology, University of Texas at
Austin, Austin, United States,Department of Molecular
Biosciences, University of Texas at
Austin, Austin, United States,For correspondence:
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14
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Putnam AA, Jankowsky E. AMP sensing by DEAD-box RNA helicases. J Mol Biol 2013; 425:3839-45. [PMID: 23702290 DOI: 10.1016/j.jmb.2013.05.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Revised: 05/10/2013] [Accepted: 05/14/2013] [Indexed: 11/18/2022]
Abstract
In eukaryotes, cellular levels of adenosine monophosphate (AMP) signal the metabolic state of the cell. AMP concentrations increase significantly upon metabolic stress, such as glucose deprivation in yeast. Here, we show that several DEAD-box RNA helicases are sensitive to AMP, which is not produced during ATP hydrolysis by these enzymes. We find that AMP potently inhibits RNA binding and unwinding by the yeast DEAD-box helicases Ded1p, Mss116p, and eIF4A. However, the yeast DEAD-box helicases Sub2p and Dbp5p are not inhibited by AMP. Our observations identify a subset of DEAD-box helicases as enzymes with the capacity to directly link changes in AMP concentrations to RNA metabolism.
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Affiliation(s)
- Andrea A Putnam
- Center for RNA Molecular Biology and Department of Biochemistry, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA
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15
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Steimer L, Wurm JP, Linden MH, Rudolph MG, Wöhnert J, Klostermeier D. Recognition of two distinct elements in the RNA substrate by the RNA-binding domain of the T. thermophilus DEAD box helicase Hera. Nucleic Acids Res 2013; 41:6259-72. [PMID: 23625962 PMCID: PMC3695512 DOI: 10.1093/nar/gkt323] [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: 11/25/2022] Open
Abstract
DEAD box helicases catalyze the ATP-dependent destabilization of RNA duplexes. Whereas duplex separation is mediated by the helicase core shared by all members of the family, flanking domains often contribute to binding of the RNA substrate. The Thermus thermophilus DEAD-box helicase Hera (for “heat-resistant RNA-binding ATPase”) contains a C-terminal RNA-binding domain (RBD). We have analyzed RNA binding to the Hera RBD by a combination of mutational analyses, nuclear magnetic resonance and X-ray crystallography, and identify residues on helix α1 and the C-terminus as the main determinants for high-affinity RNA binding. A crystal structure of the RBD in complex with a single-stranded RNA resolves the RNA–protein interactions in the RBD core region around helix α1. Differences in RNA binding to the Hera RBD and to the structurally similar RBD of the Bacillus subtilis DEAD box helicase YxiN illustrate the versatility of RNA recognition motifs as RNA-binding platforms. Comparison of chemical shift perturbation patterns elicited by different RNAs, and the effect of sequence changes in the RNA on binding and unwinding show that the RBD binds a single-stranded RNA region at the core and simultaneously contacts double-stranded RNA through its C-terminal tail. The helicase core then unwinds an adjacent RNA duplex. Overall, the mode of RNA binding by Hera is consistent with a possible function as a general RNA chaperone.
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Affiliation(s)
- Lenz Steimer
- Institute for Physical Chemistry, University of Muenster, Corrensstrasse 30, D-48149 Muenster, Germany
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16
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Putnam AA, Jankowsky E. DEAD-box helicases as integrators of RNA, nucleotide and protein binding. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2013; 1829:884-93. [PMID: 23416748 DOI: 10.1016/j.bbagrm.2013.02.002] [Citation(s) in RCA: 148] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Revised: 02/04/2013] [Accepted: 02/06/2013] [Indexed: 01/10/2023]
Abstract
DEAD-box helicases perform diverse cellular functions in virtually all steps of RNA metabolism from Bacteria to Humans. Although DEAD-box helicases share a highly conserved core domain, the enzymes catalyze a wide range of biochemical reactions. In addition to the well established RNA unwinding and corresponding ATPase activities, DEAD-box helicases promote duplex formation and displace proteins from RNA. They can also function as assembly platforms for larger ribonucleoprotein complexes, and as metabolite sensors. This review aims to provide a perspective on the diverse biochemical features of DEAD-box helicases and connections to structural information. We discuss these data in the context of a model that views the enzymes as integrators of RNA, nucleotide, and protein binding. This article is part of a Special Issue entitled: The Biology of RNA helicases - Modulation for life.
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Affiliation(s)
- Andrea A Putnam
- Department of Biochemistry, Case Western Reserve University, Cleveland, OH 44106, USA
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17
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Mallam AL, Del Campo M, Gilman B, Sidote DJ, Lambowitz AM. Structural basis for RNA-duplex recognition and unwinding by the DEAD-box helicase Mss116p. Nature 2012; 490:121-5. [PMID: 22940866 PMCID: PMC3465527 DOI: 10.1038/nature11402] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Accepted: 07/06/2012] [Indexed: 11/09/2022]
Abstract
DEAD-box proteins are the largest family of nucleic acid helicases and are crucial to RNA metabolism throughout all domains of life1,2. They contain a conserved ‘helicase core’ of two RecA-like domains (domains 1 and 2; D1 and D2, respectively), which uses ATP to catalyze the unwinding of short RNA duplexes by nonprocessive, local strand separation3. This mode of action differs from that of translocating helicases and allows DEAD-box proteins to remodel large RNAs and RNA-protein complexes without globally disrupting RNA structure4. However, the structural basis for this distinctive mode of RNA-unwinding remains unclear. Here, structural, biochemical, and genetic analyses of the yeast DEAD-box protein Mss116p indicate that the helicase core domains have modular functions that enable a novel mechanism for RNA duplex recognition and unwinding. By investigating D1 and D2 individually and together, we find that D1 acts as an ATP-binding domain and D2 functions as an RNA-duplex recognition domain. D2 contains a nucleic acid-binding pocket that is formed by conserved DEAD-box protein sequence motifs and accommodates A-form but not B-form duplexes, providing a basis for RNA substrate specificity. Upon a conformational change in which the two core domains join to form a ‘closed-state’ with an ATPase active site, conserved motifs in D1 promote the unwinding of duplex substrates bound to D2 by excluding one RNA strand and bending the other. Our results provide a comprehensive structural model for how DEAD-box proteins recognize and unwind RNA duplexes. This model explains key features of DEAD-box protein function and affords new perspective on how the evolutionarily related cores of other RNA and DNA helicases diverged to use different mechanisms.
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Affiliation(s)
- Anna L Mallam
- Institute for Cellular and Molecular Biology, Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, Texas 78712, USA
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18
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High-throughput genetic identification of functionally important regions of the yeast DEAD-box protein Mss116p. J Mol Biol 2011; 413:952-72. [PMID: 21945532 DOI: 10.1016/j.jmb.2011.09.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Revised: 09/08/2011] [Accepted: 09/09/2011] [Indexed: 11/21/2022]
Abstract
The Saccharomyces cerevisiae DEAD-box protein Mss116p is a general RNA chaperone that functions in splicing mitochondrial group I and group II introns. Recent X-ray crystal structures of Mss116p in complex with ATP analogs and single-stranded RNA show that the helicase core induces a bend in the bound RNA, as in other DEAD-box proteins, while a C-terminal extension (CTE) induces a second bend, resulting in RNA crimping. Here, we illuminate these structures by using high-throughput genetic selections, unigenic evolution, and analyses of in vivo splicing activity to comprehensively identify functionally important regions and permissible amino acid substitutions throughout Mss116p. The functionally important regions include those containing conserved sequence motifs involved in ATP and RNA binding or interdomain interactions, as well as previously unidentified regions, including surface loops that may function in protein-protein interactions. The genetic selections recapitulate major features of the conserved helicase motifs seen in other DEAD-box proteins but also show surprising variations, including multiple novel variants of motif III (SAT). Patterns of amino acid substitutions indicate that the RNA bend induced by the helicase core depends on ionic and hydrogen-bonding interactions with the bound RNA; identify a subset of critically interacting residues; and indicate that the bend induced by the CTE results primarily from a steric block. Finally, we identified two conserved regions-one the previously noted post II region in the helicase core and the other in the CTE-that may help displace or sequester the opposite RNA strand during RNA unwinding.
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19
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Strohmeier J, Hertel I, Diederichsen U, Rudolph MG, Klostermeier D. Changing nucleotide specificity of the DEAD-box helicase Hera abrogates communication between the Q-motif and the P-loop. Biol Chem 2011; 392:357-69. [PMID: 21391900 DOI: 10.1515/bc.2011.034] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
DEAD-box proteins disrupt or remodel RNA and protein/RNA complexes at the expense of ATP. The catalytic core is composed of two flexibly connected RecA-like domains. The N-terminal domain contains most of the motifs involved in nucleotide binding and serves as a minimalistic model for helicase/nucleotide interactions. A single conserved glutamine in the so-called Q-motif has been suggested as a conformational sensor for the nucleotide state. To reprogram the Thermus thermophilus RNA helicase Hera for use of oxo-ATP instead of ATP and to investigate the sensor function of the Q-motif, we analyzed helicase activity of Hera Q28E. Crystal structures of the Hera N-terminal domain Q28E mutant (TthDEAD_Q28E) in apo- and ligand-bound forms show that Q28E does change specificity from adenine to 8-oxoadenine. However, significant structural changes accompany the Q28E mutation, which prevent the P-loop from adopting its catalytically active conformation and explain the lack of helicase activity of Hera_Q28E with either ATP or 8-oxo-ATP as energy sources. 8-Oxo-adenosine, 8-oxo-AMP, and 8-oxo-ADP weakly bind to TthDEAD_Q28E but in non-canonical modes. These results indicate that the Q-motif not only senses the nucleotide state of the helicase but could also stabilize a catalytically competent conformation of the P-loop and other helicase signature motifs.
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Affiliation(s)
- Julian Strohmeier
- Institute for Organic and Biomolecular Chemistry, University of Göttingen, Göttingen, Germany
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20
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Invariant U2 snRNA nucleotides form a stem loop to recognize the intron early in splicing. Mol Cell 2010; 38:416-27. [PMID: 20471947 DOI: 10.1016/j.molcel.2010.02.036] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2009] [Revised: 09/10/2009] [Accepted: 02/16/2010] [Indexed: 12/16/2022]
Abstract
U2 snRNA-intron branchpoint pairing is a critical step in pre-mRNA recognition by the splicing apparatus, but the mechanism by which these two RNAs engage each other is unknown. Here, we identify a U2 snRNA structure, the branchpoint-interacting stem loop (BSL), which presents the U2 nucleotides that will contact the intron. We provide evidence that the BSL forms prior to interaction with the intron and is disrupted by the DExD/H protein Prp5p during engagement of the snRNA with the intron. In vitro splicing complex assembly in a BSL-destabilized mutant extract suggests that the BSL is required at a previously unrecognized step between commitment complex and prespliceosome formation. The extreme evolutionary conservation of the BSL suggests that it represents an ancient structural solution to the problem of intron branchpoint recognition by dynamic RNA elements that must serve multiple functions at other times during splicing.
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21
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Schütz P, Wahlberg E, Karlberg T, Hammarström M, Collins R, Flores A, Schüler H. Crystal structure of human RNA helicase A (DHX9): structural basis for unselective nucleotide base binding in a DEAD-box variant protein. J Mol Biol 2010; 400:768-82. [PMID: 20510246 DOI: 10.1016/j.jmb.2010.05.046] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2010] [Revised: 05/04/2010] [Accepted: 05/19/2010] [Indexed: 11/28/2022]
Abstract
RNA helicases of the DExD/H-box superfamily are critically involved in all RNA-related processes. No crystal structures of human DExH-box domains had been determined previously, and their structures were difficult to predict owing to the low level of homology among DExH-motif-containing proteins from diverse species. Here we present the crystal structures of the conserved domain 1 of the DEIH-motif-containing helicase DHX9 and of the DEAD-box helicase DDX20. Both contain a RecA-like core, but DHX9 differs from DEAD-box proteins in the arrangement of secondary structural elements and is more similar to viral helicases such as NS3. The N-terminus of the DHX9 core contains two long alpha-helices that reside on the surface of the core without contributing to nucleotide binding. The RNA-polymerase-II-interacting minimal transactivation domain sequence forms an extended loop structure that resides in a hydrophobic groove on the surface of the DEIH domain. DHX9 lacks base-selective contacts and forms an unspecific but important stacking interaction with the base of the bound nucleotide, and our biochemical analysis confirms that the protein can hydrolyze ATP, guanosine 5'-triphosphate, cytidine 5'-triphosphate, and uridine 5'-triphosphate. Together, these findings allow the localization of functional motifs within the three-dimensional structure of a human DEIH helicase and show how these enzymes can bind nucleotide with high affinity in the absence of a Q-motif.
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Affiliation(s)
- Patrick Schütz
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
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22
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Despins S, Issur M, Bougie I, Bisaillon M. Deciphering the molecular basis for nucleotide selection by the West Nile virus RNA helicase. Nucleic Acids Res 2010; 38:5493-506. [PMID: 20421212 PMCID: PMC2938200 DOI: 10.1093/nar/gkq276] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The West Nile virus RNA helicase uses the energy derived from the hydrolysis of nucleotides to separate complementary strands of RNA. Although this enzyme has a preference for ATP, the bias towards this purine nucleotide cannot be explained on the basis of specific protein–ATP interactions. Moreover, the enzyme does not harbor the characteristic Q-motif found in other helicases that regulates binding to ATP. In the present study, we used structural homology modeling to generate a model of the West Nile virus RNA helicase active site that provides instructive findings on the interaction between specific amino acids and the ATP substrate. In addition, we evaluated both the phosphohydrolysis and the inhibitory potential of a collection of 30 synthetic purine analogs. A structure-guided alanine scan of 16 different amino acids was also performed to clarify the contacts that are made between the enzyme and ATP. Our study provides a molecular rationale for the bias of the enzyme for ATP by highlighting the specific functional groups on ATP that are important for binding. Moreover, we identified three new essential amino acids (Arg-185, Arg-202 and Asn-417) that are critical for phosphohydrolysis. Finally, we provide evidence that a region located upstream of motif I, which we termed the nucleotide specificity region, plays a functional role in nucleotide selection which is reminiscent to the role exerted by the Q-motif found in other helicases.
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Affiliation(s)
- Simon Despins
- RNA Group/Groupe ARN, Département de Biochimie, Faculté de Médecine, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
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23
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Hilbert M, Karow AR, Klostermeier D. The mechanism of ATP-dependent RNA unwinding by DEAD box proteins. Biol Chem 2010; 390:1237-50. [PMID: 19747077 DOI: 10.1515/bc.2009.135] [Citation(s) in RCA: 117] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
DEAD box proteins catalyze the ATP-dependent unwinding of double-stranded RNA (dsRNA). In addition, they facilitate protein displacement and remodeling of RNA or RNA/protein complexes. Their hallmark feature is local destabilization of RNA duplexes. Here, we summarize current data on the DEAD box protein mechanism and present a model for RNA unwinding that integrates recent data on the effect of ATP analogs and mutations on DEAD box protein activity. DEAD box proteins share a conserved helicase core with two flexibly linked RecA-like domains that contain all helicase signature motifs. Variable flanking regions contribute to substrate binding and modulate activity. In the presence of ATP and RNA, the helicase core adopts a compact, closed conformation with extensive interdomain contacts and high affinity for RNA. In the closed conformation, the RecA-like domains form a catalytic site for ATP hydrolysis and a continuous RNA binding site. A kink in the backbone of the bound RNA locally destabilizes the duplex. Rearrangement of this initial complex generates a hydrolysis- and unwinding-competent state. From this complex, the first RNA strand can dissociate. After ATP hydrolysis and phosphate release, the DEAD box protein returns to a low-affinity state for RNA. Dissociation of the second RNA strand and reopening of the cleft in the helicase core allow for further catalytic cycles.
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Affiliation(s)
- Manuel Hilbert
- Biozentrum, Biophysical Chemistry, University of Basel, Klingelbergstrasse 70, CH-4056 Basel, Switzerland
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24
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Rudolph MG, Klostermeier D. The Thermus thermophilus DEAD box helicase Hera contains a modified RNA recognition motif domain loosely connected to the helicase core. RNA (NEW YORK, N.Y.) 2009; 15:1993-2001. [PMID: 19710183 PMCID: PMC2764482 DOI: 10.1261/rna.1820009] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
DEAD box family helicases consist of a helicase core that is formed by two flexibly linked RecA-like domains. The helicase activity can be regulated by N- or C-terminal extensions flanking the core. Thermus thermophilus heat resistant RNA-dependent ATPase (Hera) is the first DEAD box helicase that forms a dimer using a unique dimerization domain. In addition to the dimerization domain, Hera contains a C-terminal RNA binding domain (RBD) that shares sequence homology only to uncharacterized proteins of the Deinococcus/Thermus group. The crystal structure of Hera_RBD reveals the fold of an altered RNA recognition motif (RRM) with limited structural homology to the RBD of the DEAD box helicase YxiN from Bacillus subtilis. Comparison with RRM/RNA complexes shows that a RNA binding mode different than that suggested for YxiN, but similar to U1A, can be inferred for Hera. The orientation of the RBD relative to the helicase core was defined in a second crystal structure of a Hera fragment including the C-terminal RecA domain, the dimerization domain, and the RBD. The structures allow construction of a model for the entire Hera helicase dimer. A likely binding surface for large RNA substrates that spans both RecA-like domains and the RBD is identified.
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Affiliation(s)
- Markus G Rudolph
- Department of Molecular Structural Biology, University of Göttingen, D-37077 Göttingen, Germany
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25
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Sinha KM, Glickman MS, Shuman S. Mutational analysis of Mycobacterium UvrD1 identifies functional groups required for ATP hydrolysis, DNA unwinding, and chemomechanical coupling. Biochemistry 2009; 48:4019-30. [PMID: 19317511 DOI: 10.1021/bi900103d] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Mycobacterial UvrD1 is a DNA-dependent ATPase and a Ku-dependent 3' to 5' DNA helicase. The UvrD1 motor domain resembles that of the prototypal superfamily I helicases UvrD and PcrA. Here we performed a mutational analysis of UvrD1 guided by the crystal structure of a DNA-bound Escherichia coli UvrD-ADP-MgF(3) transition state mimetic. Alanine scanning and conservative substitutions identified amino acids essential for both ATP hydrolysis and duplex unwinding, including those implicated in phosphohydrolase chemistry via transition state stabilization (Arg308, Arg648, Gln275), divalent cation coordination (Glu236), or activation of the nucleophilic water (Glu236, Gln275). Other residues important for ATPase/helicase activity include Phe280 and Phe72, which interact with the DNA 3' single strand tail. ATP hydrolysis was uncoupled from duplex unwinding by mutations at Glu609 (in helicase motif V), which contacts the ATP ribose sugar. Introducing alanine in lieu of the adenine-binding "Q motif" glutamine (Gln24) relaxed the substrate specificity in NTP hydrolysis, e.g., eliciting a gain of function as a UTPase/TTPase, although the Q24A mutant still relied on ATP/dATP for duplex unwinding. Our studies highlight the role of the Q motif as a substrate filter and the contributions of adenosine-binding residues as couplers of NTP hydrolysis to motor activity. The Ku-binding function of UvrD1 lies within its C-terminal 270 amino acid segment. Here we found that deleting the 90 amino acid C-terminal domain, which is structurally uncharacterized, diminished DNA unwinding, without affecting ATP hydrolysis or binding to the DNA helicase substrate, apparently by affecting the strength of the UvrD1-Ku interaction.
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Affiliation(s)
- Krishna Murari Sinha
- Molecular Biology Program, Sloan-Kettering Institute, New York, New York 10021, USA
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26
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Fan JS, Cheng Z, Zhang J, Noble C, Zhou Z, Song H, Yang D. Solution and crystal structures of mRNA exporter Dbp5p and its interaction with nucleotides. J Mol Biol 2009; 388:1-10. [PMID: 19281819 DOI: 10.1016/j.jmb.2009.03.004] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2008] [Revised: 02/28/2009] [Accepted: 03/03/2009] [Indexed: 11/19/2022]
Abstract
DEAD-box protein 5 (Dbp5p) plays very important roles in RNA metabolism from transcription, to translation, to RNA decay. It is an RNA helicase and functions as an essential RNA export factor from nucleus. Here, we report the solution NMR structures of the N- and C-terminal domains (NTD and CTD, respectively) of Dbp5p from Saccharomyces cerevisiae (ScDbp5p) and X-ray crystal structure of Dbp5p from Schizosaccharomyces pombe (SpDbp5p) in the absence of nucleotides and RNA. The crystal structure clearly shows that SpDbp5p comprises two RecA-like domains that do not interact with each other. NMR results show that the N-terminal flanking region of ScDpbp5 (M1-E70) is intrinsically unstructured and the region Y71-R121 including the Q motif is highly dynamic on millisecond-microsecond timescales in solution. The C-terminal flanking region of ScDbp5p forms a short beta-strand and a long helix. This helix is unique for ScDbp5p and has not been observed in other DEAD-box proteins. Compared with other DEAD-box proteins, Dbp5p has an extra insert with six residues in the CTD. NMR structure reveals that the insert is located in a solvent-exposed loop capable of interacting with other proteins. ATP and ADP titration experiments show that both ADP and ATP bind to the consensus binding site in the NTD of ScDbp5p but do not interact with the CTD at all. Binding of ATP or ADP to NTD induces significant conformational rearrangement too.
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Affiliation(s)
- Jing-Song Fan
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543, Singapore
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27
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Rudolph MG, Wittmann JG, Klostermeier D. Crystallization and preliminary characterization of the Thermus thermophilus RNA helicase Hera C-terminal domain. Acta Crystallogr Sect F Struct Biol Cryst Commun 2009; 65:248-52. [PMID: 19255475 DOI: 10.1107/s1744309108043145] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2008] [Accepted: 12/18/2008] [Indexed: 11/10/2022]
Abstract
Heat-resistant RNA-dependent ATPase (Hera) from Thermus thermophilus is a DEAD-box RNA helicase. Two constructs encompassing the second RecA-like domain and the C-terminal domain of Hera were overproduced in Escherichia coli and purified to homogeneity. Single crystals of both Hera constructs were obtained in three crystal forms. A tetragonal crystal form belonged to space group P4(1)2(1)2, with unit-cell parameters a = 65.5, c = 153.0 A, and contained one molecule per asymmetric unit. Two orthorhombic forms belonged to space group P2(1)2(1)2(1), with unit-cell parameters a = 62.8, b = 70.9, c = 102.3 A (form I) and a = 41.6, b = 67.6, c = 183.5 A (form II). Both orthorhombic forms contained two molecules per asymmetric unit. All crystals diffracted X-rays to beyond 3 A resolution, but the tetragonal data sets displayed high Wilson B values and high mean |E(2) - 1| values, indicating potential disorder and anisotropy. The tetragonal crystal was phased by MAD using a single selenium site.
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Affiliation(s)
- Markus G Rudolph
- Department of Molecular Structural Biology, Institute for Microbiology and Genetics, Georg-August-Universität, Göttingen, Germany
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28
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Klostermeier D, Rudolph MG. A novel dimerization motif in the C-terminal domain of the Thermus thermophilus DEAD box helicase Hera confers substantial flexibility. Nucleic Acids Res 2008; 37:421-30. [PMID: 19050012 PMCID: PMC2632915 DOI: 10.1093/nar/gkn947] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
DEAD box helicases are involved in nearly all aspects of RNA metabolism. They share a common helicase core, and may comprise additional domains that contribute to RNA binding. The Thermus thermophilus helicase Hera is the first dimeric DEAD box helicase. Crystal structures of Hera fragments reveal a bipartite C-terminal domain with a novel dimerization motif and an RNA-binding module. We provide a first glimpse on the additional RNA-binding module outside the Hera helicase core. The dimerization and RNA-binding domains are connected to the C-terminal RecA domain by a hinge region that confers exceptional flexibility onto the helicase, allowing for different juxtapositions of the RecA-domains in the dimer. Combination of the previously determined N-terminal Hera structure with the C-terminal Hera structures allows generation of a model for the entire Hera dimer, where two helicase cores can work in conjunction on large RNA substrates.
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Affiliation(s)
- Dagmar Klostermeier
- Division of Biophysical Chemistry, Biozentrum, University of Basel, CH-4056 Basel, Switzerland.
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29
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Linden MH, Hartmann RK, Klostermeier D. The putative RNase P motif in the DEAD box helicase Hera is dispensable for efficient interaction with RNA and helicase activity. Nucleic Acids Res 2008; 36:5800-11. [PMID: 18782831 PMCID: PMC2566870 DOI: 10.1093/nar/gkn581] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
DEAD box helicases use the energy of ATP hydrolysis to remodel RNA structures or RNA/protein complexes. They share a common helicase core with conserved signature motifs, and additional domains may confer substrate specificity. Identification of a specific substrate is crucial towards understanding the physiological role of a helicase. RNA binding and ATPase stimulation are necessary, but not sufficient criteria for a bona fide helicase substrate. Here, we report single molecule FRET experiments that identify fragments of the 23S rRNA comprising hairpin 92 and RNase P RNA as substrates for the Thermus thermophilus DEAD box helicase Hera. Both substrates induce a switch to the closed conformation of the helicase core and stimulate the intrinsic ATPase activity of Hera. Binding of these RNAs is mediated by the Hera C-terminal domain, but does not require a previously proposed putative RNase P motif within this domain. ATP-dependent unwinding of a short helix adjacent to hairpin 92 in the ribosomal RNA suggests a specific role for Hera in ribosome assembly, analogously to the Escherichia coli and Bacillus subtilis helicases DbpA and YxiN. In addition, the specificity of Hera for RNase P RNA may be required for RNase P RNA folding or RNase P assembly.
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Affiliation(s)
- Martin H Linden
- Department of Biophysical Chemistry, Biozentrum, University of Basel, Klingelbergstrasse 70, 4056 Basel, Switzerland
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30
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Abstract
Understanding how RNA folds and what causes it to unfold has become more important as knowledge of the diverse functions of RNA has increased. Here we review the contributions of single-molecule experiments to providing answers to questions such as: How much energy is required to unfold a secondary or tertiary structure? How fast is the process? How do helicases unwind double helices? Are the unwinding activities of RNA-dependent RNA polymerases and of ribosomes different from other helicases? We discuss the use of optical tweezers to monitor the unfolding activities of helicases, polymerases, and ribosomes, and to apply force to unfold RNAs directly. We also review the applications of fluorescence and fluorescence resonance energy transfer to measure RNA dynamics.
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Affiliation(s)
- Pan T X Li
- Department of Biological Sciences, University at Albany, State University of New York, Albany, NY 12222, USA.
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31
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Theissen B, Karow AR, Köhler J, Gubaev A, Klostermeier D. Cooperative binding of ATP and RNA induces a closed conformation in a DEAD box RNA helicase. Proc Natl Acad Sci U S A 2008; 105:548-53. [PMID: 18184816 PMCID: PMC2206573 DOI: 10.1073/pnas.0705488105] [Citation(s) in RCA: 124] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2007] [Indexed: 11/18/2022] Open
Abstract
RNA helicases couple the energy from ATP hydrolysis with structural changes of their RNA substrates. DEAD box helicases form the largest class of RNA helicases and share a helicase core comprising two RecA-like domains. An opening and closing of the interdomain cleft during RNA unwinding has been postulated but not shown experimentally. Single-molecule FRET experiments with the Bacillus subtilis DEAD box helicase YxiN carrying donor and acceptor fluorophores on different sides of the interdomain cleft reveal an open helicase conformation in the absence of nucleotides, or in the presence of ATP, or ADP, or RNA. In the presence of ADP and RNA, the open conformation is retained. By contrast, cooperative binding of ATP and RNA leads to a compact helicase structure, proving that the ATP- and ADP-bound states of RNA helicases display substantially different structures only when the RNA substrate is bound. These results establish a closure of the interdomain cleft in the helicase core at the beginning of the unwinding reaction, and suggest a conserved mechanism of energy conversion among DEAD box helicases across kingdoms.
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Affiliation(s)
- Bettina Theissen
- Department of Biophysical Chemistry, University of Basel, Klingelbergstrasse 70, 4056 Basel, Switzerland; and
| | - Anne R. Karow
- Department of Biophysical Chemistry, University of Basel, Klingelbergstrasse 70, 4056 Basel, Switzerland; and
| | - Jürgen Köhler
- Department of Experimental Physics IV, University of Bayreuth, Universitätsstrasse 30, 95440 Bayreuth, Germany
| | - Airat Gubaev
- Department of Biophysical Chemistry, University of Basel, Klingelbergstrasse 70, 4056 Basel, Switzerland; and
| | - Dagmar Klostermeier
- Department of Biophysical Chemistry, University of Basel, Klingelbergstrasse 70, 4056 Basel, Switzerland; and
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32
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Högbom M, Collins R, van den Berg S, Jenvert RM, Karlberg T, Kotenyova T, Flores A, Karlsson Hedestam GB, Schiavone LH. Crystal structure of conserved domains 1 and 2 of the human DEAD-box helicase DDX3X in complex with the mononucleotide AMP. J Mol Biol 2007; 372:150-9. [PMID: 17631897 DOI: 10.1016/j.jmb.2007.06.050] [Citation(s) in RCA: 107] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2007] [Revised: 06/12/2007] [Accepted: 06/14/2007] [Indexed: 11/24/2022]
Abstract
DExD-box helicases are involved in all aspects of cellular RNA metabolism. Conserved domains 1 and 2 contain nine signature motifs that are responsible for nucleotide binding, RNA binding and ATP hydrolysis. The human DEAD-box helicase DDX3X has been associated with several different cellular processes, such as cell-growth control, mRNA transport and translation, and is suggested to be essential for the export of unspliced/partially spliced HIV mRNAs from the nucleus to the cytoplasm. Here, the crystal structure of conserved domains 1 and 2 of DDX3X, including a DDX3-specific insertion that is not generally found in human DExD-box helicases, is presented. The N-terminal domain 1 and the C-terminal domain 2 both display RecA-like folds comprising a central beta-sheet flanked by alpha-helices. Interestingly, the DDX3X-specific insertion forms a helical element that extends a highly positively charged sequence in a loop, thus increasing the RNA-binding surface of the protein. Surprisingly, although DDX3X was crystallized in the presence of a large excess of ADP or the slowly hydrolyzable ATP analogue ATPgammaS the contaminant AMP was seen in the structure. A fluorescent-based stability assay showed that the thermal stability of DDX3X was increased by the mononucleotide AMP but not by ADP or ATPgammaS, suggesting that DDX3X is stabilized by AMP and elucidating why AMP was found in the nucleotide-binding pocket.
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Affiliation(s)
- Martin Högbom
- Structural Genomics Consortium, Department of Medical Biochemistry and Biophysics, Karolinska Institute, SE-171 77 Stockholm, Sweden
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