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Inlow K, Tenenbaum D, Friedman LJ, Kondev J, Gelles J. Recycling of bacterial RNA polymerase by the Swi2/Snf2 ATPase RapA. Proc Natl Acad Sci U S A 2023; 120:e2303849120. [PMID: 37406096 PMCID: PMC10334767 DOI: 10.1073/pnas.2303849120] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 05/30/2023] [Indexed: 07/07/2023] Open
Abstract
Free-living bacteria have regulatory systems that can quickly reprogram gene transcription in response to changes in the cellular environment. The RapA ATPase, a prokaryotic homolog of the eukaryotic Swi2/Snf2 chromatin remodeling complex, may facilitate such reprogramming, but the mechanisms by which it does so are unclear. We used multiwavelength single-molecule fluorescence microscopy in vitro to examine RapA function in the Escherichia coli transcription cycle. In our experiments, RapA at <5 nM concentration did not appear to alter transcription initiation, elongation, or intrinsic termination. Instead, we directly observed a single RapA molecule bind specifically to the kinetically stable post termination complex (PTC)-consisting of core RNA polymerase (RNAP)-bound sequence nonspecifically to double-stranded DNA-and efficiently remove RNAP from DNA within seconds in an ATP-hydrolysis-dependent reaction. Kinetic analysis elucidates the process through which RapA locates the PTC and the key mechanistic intermediates that bind and hydrolyze ATP. This study defines how RapA participates in the transcription cycle between termination and initiation and suggests that RapA helps set the balance between global RNAP recycling and local transcription reinitiation in proteobacterial genomes.
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Affiliation(s)
- Koe Inlow
- Department of Biochemistry, Brandeis University, Waltham, MA02453
| | | | | | - Jane Kondev
- Department of Physics, Brandeis University, Waltham, MA02453
| | - Jeff Gelles
- Department of Biochemistry, Brandeis University, Waltham, MA02453
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Inlow K, Tenenbaum D, Friedman LJ, Kondev J, Gelles J. Recycling of Bacterial RNA Polymerase by the Swi2/Snf2 ATPase RapA.. [DOI: 10.1101/2023.03.22.533849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
Abstract
ABSTRACTFree-living bacteria have regulatory systems that can quickly reprogram gene transcription in response to changes in cellular environment. The RapA ATPase, a prokaryotic homolog of the eukaryote Swi2/Snf2 chromatin remodeling complex, may facilitate such reprogramming, but the mechanisms by which it does so is unclear. We used multi-wavelength single-molecule fluorescence microscopy in vitro to examine RapA function in theE. colitranscription cycle. In our experiments, RapA at < 5 nM concentration did not appear to alter transcription initiation, elongation, or intrinsic termination. Instead, we directly observed a single RapA molecule bind specifically to the kinetically stable post-termination complex (PTC) -- consisting of core RNA polymerase (RNAP) bound to dsDNA -- and efficiently remove RNAP from DNA within seconds in an ATP-hydrolysis-dependent reaction. Kinetic analysis elucidates the process through which RapA locates the PTC and the key mechanistic intermediates that bind and hydrolyze ATP. This study defines how RapA participates in the transcription cycle between termination and initiation and suggests that RapA helps set the balance between global RNAP recycling and local transcription re-initiation in proteobacterial genomes.SIGNIFICANCERNA synthesis is an essential conduit of genetic information in all organisms. After transcribing an RNA, the bacterial RNA polymerase (RNAP) must be reused to make subsequent RNAs, but the steps that enable RNAP reuse are unclear. We directly observed the dynamics of individual molecules of fluorescently labeled RNAP and the enzyme RapA as they colocalized with DNA during and after RNA synthesis. Our studies show that RapA uses ATP hydrolysis to remove RNAP from DNA after the RNA is released from RNAP and reveal essential features of the mechanism by which this removal occurs. These studies fill in key missing pieces in our current understanding of the events that occur after RNA is released and that enable RNAP reuse.
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Qayyum MZ, Molodtsov V, Renda A, Murakami KS. Structural basis of RNA polymerase recycling by the Swi2/Snf2 family of ATPase RapA in Escherichia coli. J Biol Chem 2021; 297:101404. [PMID: 34774797 PMCID: PMC8666675 DOI: 10.1016/j.jbc.2021.101404] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 11/02/2021] [Accepted: 11/09/2021] [Indexed: 01/27/2023] Open
Abstract
After transcription termination, cellular RNA polymerases (RNAPs) are occasionally trapped on DNA, impounded in an undefined post-termination complex (PTC), limiting the free RNAP pool and subsequently leading to inefficient transcription. In Escherichia coli, a Swi2/Snf2 family of ATPase called RapA is known to be involved in countering such inefficiency through RNAP recycling; however, the precise mechanism of this recycling is unclear. To better understand its mechanism, here we determined the structures of two sets of E. coli RapA–RNAP complexes, along with the RNAP core enzyme and the elongation complex, using cryo-EM. These structures revealed the large conformational changes of RNAP and RapA upon their association that has been implicated in the hindrance of PTC formation. Our results along with DNA-binding assays reveal that although RapA binds RNAP away from the DNA-binding main channel, its binding can allosterically close the RNAP clamp, thereby preventing its nonspecific DNA binding and PTC formation. Taken together, we propose that RapA acts as a guardian of RNAP by which RapA prevents nonspecific DNA binding of RNAP without affecting the binding of promoter DNA recognition σ factor, thereby enhancing RNAP recycling.
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Affiliation(s)
- M Zuhaib Qayyum
- Department of Biochemistry and Molecular Biology, The Center for RNA Molecular Biology, The Center for Structural Biology, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Vadim Molodtsov
- Department of Biochemistry and Molecular Biology, The Center for RNA Molecular Biology, The Center for Structural Biology, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Andrew Renda
- Department of Biochemistry and Molecular Biology, The Center for RNA Molecular Biology, The Center for Structural Biology, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Katsuhiko S Murakami
- Department of Biochemistry and Molecular Biology, The Center for RNA Molecular Biology, The Center for Structural Biology, Pennsylvania State University, University Park, Pennsylvania, USA.
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Shi W, Zhou W, Chen M, Yang Y, Hu Y, Liu B. Structural basis for activation of Swi2/Snf2 ATPase RapA by RNA polymerase. Nucleic Acids Res 2021; 49:10707-10716. [PMID: 34428297 PMCID: PMC8501970 DOI: 10.1093/nar/gkab744] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 08/09/2021] [Accepted: 08/13/2021] [Indexed: 11/14/2022] Open
Abstract
RapA is a bacterial RNA polymerase (RNAP)-associated Swi2/Snf2 ATPase that stimulates RNAP recycling. The ATPase activity of RapA is autoinhibited by its N-terminal domain (NTD) but activated with RNAP bound. Here, we report a 3.4-Å cryo-EM structure of Escherichia coli RapA-RNAP elongation complex, in which the ATPase active site of RapA is structurally remodeled. In this process, the NTD of RapA is wedged open by RNAP β' zinc-binding domain (ZBD). In addition, RNAP β flap tip helix (FTH) forms extensive hydrophobic interactions with RapA ATPase core domains. Functional assay demonstrates that removing the ZBD or FTH of RNAP significantly impairs its ability to activate the ATPase activity of RapA. Our results provide the structural basis of RapA ATPase activation by RNAP, through the active site remodeling driven by the ZBD-buttressed large-scale opening of NTD and the direct interactions between FTH and ATPase core domains.
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Affiliation(s)
- Wei Shi
- Section of Transcription & Gene Regulation, The Hormel Institute, University of Minnesota, Austin, MN 55912, USA
| | - Wei Zhou
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan 430071, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ming Chen
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan 430071, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yang Yang
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA 50011, USA
| | - Yangbo Hu
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan 430071, China
| | - Bin Liu
- Section of Transcription & Gene Regulation, The Hormel Institute, University of Minnesota, Austin, MN 55912, USA
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Song H, Fang X, Jin L, Shaw GX, Wang YX, Ji X. The Functional Cycle of Rnt1p: Five Consecutive Steps of Double-Stranded RNA Processing by a Eukaryotic RNase III. Structure 2017; 25:353-363. [PMID: 28111020 PMCID: PMC5299047 DOI: 10.1016/j.str.2016.12.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2016] [Revised: 11/24/2016] [Accepted: 12/21/2016] [Indexed: 12/29/2022]
Abstract
Double-stranded RNA (dsRNA)-specific RNase III proteins are required for RNA maturation and gene regulation. The mechanism of prokaryotic RNase IIIs has been well characterized, but how eukaryotic RNase IIIs (exemplified by Rnt1p, Drosha, and Dicer) work is less clear. Recently, we reported the crystal structure of Rnt1p in complex with RNA, revealing a double-ruler mechanism for substrate selection. Here, we present more structures of Rnt1p, either RNA free or RNA bound, featuring two major conformations of the enzyme. Using these structures with existing data, we describe the functional cycle of Rnt1p in five steps, selecting, loading, locking, cleavage, and releasing. We also describe atomic details of the two-Mg2+-ion catalytic mechanism that is applicable to all eukaryotic RNase III enzymes. Overall, our results indicate that substrate selection is achieved independent of cleavage, allowing the recognition of substrates with different structures while preserving the basic mechanism of cleavage.
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Affiliation(s)
- He Song
- Macromolecular Crystallography Laboratory, National Cancer Institute, Frederick, MD 21702, USA
| | - Xianyang Fang
- Structural Biophysics Laboratory, National Cancer Institute, Frederick, MD 21702, USA
| | - Lan Jin
- Macromolecular Crystallography Laboratory, National Cancer Institute, Frederick, MD 21702, USA
| | - Gary X Shaw
- Macromolecular Crystallography Laboratory, National Cancer Institute, Frederick, MD 21702, USA
| | - Yun-Xing Wang
- Structural Biophysics Laboratory, National Cancer Institute, Frederick, MD 21702, USA
| | - Xinhua Ji
- Macromolecular Crystallography Laboratory, National Cancer Institute, Frederick, MD 21702, USA.
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