1
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Prieto VA, Namitz KEW, Showalter SA. Transient Electrostatic Interactions between Fcp1 and Rap74 Bias the Conformational Ensemble of the Complex with Minimal Impact on Binding Affinity. J Phys Chem B 2021; 125:10917-10927. [PMID: 34550709 DOI: 10.1021/acs.jpcb.1c05131] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Intrinsically disordered protein (IDP) sequences often contain a high proportion of charged residues in conjunction with their high degree of hydrophilicity and solvation. For high net charge IDPs, long-range electrostatic interactions are thought to play a role in modulating the strength or kinetics of protein-protein interactions. In this work, we examined intramolecular interactions mediated by charged regions of a model IDP, the C-terminal tail of the phosphatase Fcp1. Specifically, this work focuses on intermolecular interactions between acidic and basic patches in the primary structure of Fcp1 and their contributions to binding its predominantly basic partner, the winged helix domain of Rap74. We observe both intramolecular and intermolecular interactions through paramagnetic relaxation enhancement (PRE) consistent with oppositely charged regions associating with one another, both in unbound Fcp1 and in the Fcp1-Rap74 complex. Formation of this complex is strongly driven by hydrophobic interactions in the minimal binding motif. Here, we test the hypothesis that charged residues in Fcp1 that flank the binding helix also contribute to the strength of binding. Charge inversion mutations in Fcp1 generally support this hypothesis, while PRE data suggest substitution of observed transient interactions in the unbound ensemble for similarly transient interactions with Rap74 in the complex.
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Affiliation(s)
- Victor A Prieto
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Kevin E W Namitz
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Scott A Showalter
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States.,Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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2
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Abstract
RNA polymerase II (Pol II) transcribes all protein-coding genes and many noncoding RNAs in eukaryotic genomes. Although Pol II is a complex, 12-subunit enzyme, it lacks the ability to initiate transcription and cannot consistently transcribe through long DNA sequences. To execute these essential functions, an array of proteins and protein complexes interact with Pol II to regulate its activity. In this review, we detail the structure and mechanism of over a dozen factors that govern Pol II initiation (e.g., TFIID, TFIIH, and Mediator), pausing, and elongation (e.g., DSIF, NELF, PAF, and P-TEFb). The structural basis for Pol II transcription regulation has advanced rapidly in the past decade, largely due to technological innovations in cryoelectron microscopy. Here, we summarize a wealth of structural and functional data that have enabled a deeper understanding of Pol II transcription mechanisms; we also highlight mechanistic questions that remain unanswered or controversial.
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Affiliation(s)
- Allison C Schier
- Department of Biochemistry, University of Colorado, Boulder, Colorado 80303, USA
| | - Dylan J Taatjes
- Department of Biochemistry, University of Colorado, Boulder, Colorado 80303, USA
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3
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Regulation of Androgen Receptor Activity by Transient Interactions of Its Transactivation Domain with General Transcription Regulators. Structure 2017; 26:145-152.e3. [PMID: 29225078 DOI: 10.1016/j.str.2017.11.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 10/12/2017] [Accepted: 11/10/2017] [Indexed: 11/23/2022]
Abstract
The androgen receptor is a transcription factor that plays a key role in the development of prostate cancer, and its interactions with general transcription regulators are therefore of potential therapeutic interest. The mechanistic basis of these interactions is poorly understood due to the intrinsically disordered nature of the transactivation domain of the androgen receptor and the generally transient nature of the protein-protein interactions that trigger transcription. Here, we identify a motif of the transactivation domain that contributes to transcriptional activity by recruiting the C-terminal domain of subunit 1 of the general transcription regulator TFIIF. These findings provide molecular insights into the regulation of androgen receptor function and suggest strategies for treating castration-resistant prostate cancer.
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4
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Gibbs EB, Showalter SA. Quantification of Compactness and Local Order in the Ensemble of the Intrinsically Disordered Protein FCP1. J Phys Chem B 2016; 120:8960-9. [DOI: 10.1021/acs.jpcb.6b06934] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Eric B. Gibbs
- Department
of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Scott A. Showalter
- Department
of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Department
of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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5
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Assessing Coupled Protein Folding and Binding Through Temperature-Dependent Isothermal Titration Calorimetry. Methods Enzymol 2016; 567:23-45. [DOI: 10.1016/bs.mie.2015.07.032] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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6
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Schwer B, Ghosh A, Sanchez AM, Lima CD, Shuman S. Genetic and structural analysis of the essential fission yeast RNA polymerase II CTD phosphatase Fcp1. RNA (NEW YORK, N.Y.) 2015; 21:1135-1146. [PMID: 25883047 PMCID: PMC4436666 DOI: 10.1261/rna.050286.115] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Accepted: 02/25/2015] [Indexed: 06/04/2023]
Abstract
Protein phosphatases regulate mRNA synthesis and processing by remodeling the carboxy-terminal domain (CTD) of RNA polymerase II (Pol2) to dynamically inscribe a Pol2 CTD code. Fission yeast Fcp1 (SpFcp1) is an essential 723-amino acid CTD phosphatase that preferentially hydrolyzes Ser2-PO4 of the YS(2)PTSPS repeat. The SpFcp1 catalytic domain (aa 140-580) is composed of a DxDxT acyl-phosphatase module (FCPH) and a BRCT module. Here we conducted a genetic analysis of SpFcp1, which shows that (i) phosphatase catalytic activity is required for vegetative growth of fission yeast; (ii) the flanking amino-terminal domain (aa 1-139) and its putative metal-binding motif C(99)H(101)Cys(109)C(112) are essential; (iii) the carboxy-terminal domain (aa 581-723) is dispensable; (iv) a structurally disordered internal segment of the FCPH domain (aa 330-393) is dispensable; (v) lethal SpFcp1 mutations R271A and R299A are rescued by shortening the Pol2 CTD repeat array; and (vi) CTD Ser2-PO4 is not the only essential target of SpFcp1 in vivo. Recent studies highlight a second CTD code involving threonine phosphorylation of a repeat motif in transcription elongation factor Spt5. We find that Fcp1 can dephosphorylate Thr1-PO4 of the fission yeast Spt5 CTD nonamer repeat T(1)PAWNSGSK. We identify Arg271 as a governor of Pol2 versus Spt5 CTD substrate preference. Our findings implicate Fcp1 as a versatile sculptor of both the Pol2 and Spt5 CTD codes. Finally, we report a new 1.45 Å crystal structure of SpFcp1 with Mg(2+) and AlF3 that mimics an associative phosphorane transition state of the enzyme-aspartyl-phosphate hydrolysis reaction.
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Affiliation(s)
- Beate Schwer
- Microbiology and Immunology Department, Weill Cornell Medical College, New York, New York 10065, USA
| | - Agnidipta Ghosh
- Structural Biology Program, Sloan-Kettering Institute, New York, New York 10065, USA
| | - Ana M Sanchez
- Microbiology and Immunology Department, Weill Cornell Medical College, New York, New York 10065, USA
| | - Christopher D Lima
- Structural Biology Program, Sloan-Kettering Institute, New York, New York 10065, USA Howard Hughes Medical Institute, Sloan-Kettering Institute, New York, New York 10065, USA
| | - Stewart Shuman
- Molecular Biology Program, Sloan-Kettering Institute, New York, New York 10065, USA
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7
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Rudzinski JF, Noid WG. Bottom-Up Coarse-Graining of Peptide Ensembles and Helix–Coil Transitions. J Chem Theory Comput 2015; 11:1278-91. [DOI: 10.1021/ct5009922] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Joseph F. Rudzinski
- Department
of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - William G. Noid
- Department
of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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8
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Abstract
Transcription of eukaryotic protein-coding genes commences with the assembly of a conserved initiation complex, which consists of RNA polymerase II (Pol II) and the general transcription factors, at promoter DNA. After two decades of research, the structural basis of transcription initiation is emerging. Crystal structures of many components of the initiation complex have been resolved, and structural information on Pol II complexes with general transcription factors has recently been obtained. Although mechanistic details await elucidation, available data outline how Pol II cooperates with the general transcription factors to bind to and open promoter DNA, and how Pol II directs RNA synthesis and escapes from the promoter.
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9
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Lawrence CW, Kumar S, Noid WG, Showalter SA. Role of Ordered Proteins in the Folding-Upon-Binding of Intrinsically Disordered Proteins. J Phys Chem Lett 2014; 5:833-838. [PMID: 26274075 DOI: 10.1021/jz402729x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In this work, we quantitatively investigate the thermodynamic analogy between the folding of monomeric proteins and the interactions of intrinsically disordered proteins (IDPs). Motivated by the hypothesis that similar hydrophobic forces guide both globular protein folding and also IDP interactions, we present a unified experimental and computational investigation of the coupling between the folding and binding of the intrinsically disordered tail of FCP1 when interacting with the cooperatively folding winged-helix domain of Rap74. Our calorimetric measurements quantitatively demonstrate the significance of hydrophobic interactions for this binding event. Our computational studies indicate that IDPs relieve frustration at the surface of ordered proteins to generate a minimally frustrated complex that is strikingly similar to a globular monomeric protein. In summary, these results not only quantify the thermodynamic forces driving disordered protein interactions but also highlight the role of ordered proteins for IDP function.
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Affiliation(s)
- Chad W Lawrence
- §Department of Chemistry and †Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Sushant Kumar
- §Department of Chemistry and †Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - William G Noid
- §Department of Chemistry and †Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Scott A Showalter
- §Department of Chemistry and †Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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10
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Kim JM, Won HS, Kang SO. The C-terminal domain of the transcriptional regulator BldD from Streptomyces coelicolor A3(2) constitutes a novel fold of winged-helix domains. Proteins 2013; 82:1093-8. [PMID: 24356916 DOI: 10.1002/prot.24481] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Revised: 10/30/2013] [Accepted: 11/09/2013] [Indexed: 11/10/2022]
Abstract
BldD regulates transcription of key developmental genes in Streptomyces coelicolor. While the N-terminal domain is responsible for both dimerization and DNA binding, the structural and functional roles of the C-terminal domain (CTD) remain largely unexplored. Here, the solution structure of the BldD-CTD shows a novel winged-helix domain fold not compatible with DNA binding, due to the negatively charged surface and presence of an additional helix. Meanwhile, a small elongated groove with conserved hydrophobic patches surrounded by charged residues suggests that the BldD-CTD could be involved in protein-protein interactions that provide transcriptional regulation.
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Affiliation(s)
- Jeong-Mok Kim
- Laboratory of Biophysics, School of Biological Sciences, and Institute of Microbiology, Seoul National University, Seoul, 151-742, Republic of Korea
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11
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Jeronimo C, Bataille AR, Robert F. The Writers, Readers, and Functions of the RNA Polymerase II C-Terminal Domain Code. Chem Rev 2013; 113:8491-522. [DOI: 10.1021/cr4001397] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Célia Jeronimo
- Institut de recherches cliniques de Montréal, Montréal, Québec,
Canada H2W 1R7
| | - Alain R. Bataille
- Institut de recherches cliniques de Montréal, Montréal, Québec,
Canada H2W 1R7
| | - François Robert
- Institut de recherches cliniques de Montréal, Montréal, Québec,
Canada H2W 1R7
- Département
de Médecine,
Faculté de Médecine, Université de Montréal, Montréal, Québec,
Canada H3T 1J4
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12
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Kumar S, Showalter SA, Noid WG. Native-based simulations of the binding interaction between RAP74 and the disordered FCP1 peptide. J Phys Chem B 2013; 117:3074-85. [PMID: 23387368 DOI: 10.1021/jp310293b] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
By dephosphorylating the C-terminal domain (CTD) of RNA polymerase II (Pol II), the Transcription Factor IIF (TFIIF)-associating CTD phosphatase (FCP1) performs an essential function in recycling Pol II for subsequent rounds of transcription. The interaction between FCP1 and TFIIF is mediated by the disordered C-terminal tail of FCP1, which folds to form an α-helix upon binding the RAP74 subunit of TFIIF. The present work reports a structure-based simulation study of this interaction between the folded winged-helix domain of RAP74 and the disordered C-terminal tail of FCP1. The comparison of measured and simulated chemical shifts suggests that the FCP1 peptide samples 40-60% of its native helical structure in the unbound disordered ensemble. Free energy calculations suggest that productive binding begins when RAP74 makes hydrophobic contacts with the C-terminal region of the FCP1 peptide. The FCP1 peptide then folds into an amphipathic helix by zipping up the binding interface. The relative plasticity of FCP1 results in a more cooperative binding mechanism, allows for a greater diversity of pathways leading to the bound complex, and may also eliminate the need for "backtracking" from contacts that form out of sequence.
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Affiliation(s)
- Sushant Kumar
- Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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13
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Teichmann M, Dumay-Odelot H, Fribourg S. Structural and functional aspects of winged-helix domains at the core of transcription initiation complexes. Transcription 2012; 3:2-7. [PMID: 22456313 DOI: 10.4161/trns.3.1.18917] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The winged helix (WH) domain is found in core components of transcription systems in eukaryotes and prokaryotes. It represents a sub-class of the helix-turn-helix motif. The WH domain participates in establishing protein-DNA and protein-protein-interactions. Here, we discuss possible explanations for the enrichment of this motif in transcription systems.
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Affiliation(s)
- Martin Teichmann
- Université de Bordeaux, Institut Européen de Chimie et Biologie, Pessac, France
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14
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Lawrence CW, Showalter SA. Carbon-Detected (15)N NMR Spin Relaxation of an Intrinsically Disordered Protein: FCP1 Dynamics Unbound and in Complex with RAP74. J Phys Chem Lett 2012; 3:1409-1413. [PMID: 26286791 DOI: 10.1021/jz300432e] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Intrinsically disordered proteins (IDPs) lack unique 3D structures under native conditions and as such exist as highly dynamic ensembles in solution. We present two (13)C-direct detection experiments for the measurement of (15)N NMR spin relaxation called the CON(T1)-IPAP and CON(T2)-IPAP that quantify backbone dynamics on a per-residue basis for IDPs in solution. These experiments have been applied to the intrinsically disordered C-terminal of FCP1, both free in solution and while bound to the RAP74 winged-helix domain. The results provide evidence that most of FCP1 remains highly dynamic in both states, while the 20 residues forming direct contact with RAP74 become more ordered in the complex. Parallel analysis of RAP74 backbone (15)N NMR spin relaxation reveals only very limited ordering of RAP74 upon FCP1 binding. Taken together, these data show that folding-upon-binding is highly local in this system, with disorder prevailing even in the complex.
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Affiliation(s)
- Chad W Lawrence
- Department of Chemistry, The Pennsylvania State University, 104 Chemistry Building, University Park, Pennsylvania 16802, United States
| | - Scott A Showalter
- Department of Chemistry, The Pennsylvania State University, 104 Chemistry Building, University Park, Pennsylvania 16802, United States
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15
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Moesa HA, Wakabayashi S, Nakai K, Patil A. Chemical composition is maintained in poorly conserved intrinsically disordered regions and suggests a means for their classification. MOLECULAR BIOSYSTEMS 2012; 8:3262-73. [DOI: 10.1039/c2mb25202c] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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16
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Kilpatrick AM, Koharudin LMI, Calero GA, Gronenborn AM. Structural and binding studies of the C-terminal domains of yeast TFIIF subunits Tfg1 and Tfg2. Proteins 2011; 80:519-29. [PMID: 22095626 DOI: 10.1002/prot.23217] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2011] [Revised: 09/12/2011] [Accepted: 09/27/2011] [Indexed: 12/13/2022]
Abstract
The general transcription factor TFIIF plays essential roles at several steps during eukaryotic transcription. While several studies have offered insights into the structure/function relationship in human TFIIF, much less is known about the yeast system. Here, we describe the first NMR structural and binding studies of the C-terminal domains (CTDs) of Tfg1 and Tfg2 subunits of Saccharomyces cerevisiae TFIIF. We used the program CS-ROSETTA to determine the three-dimensional folds of these domains in solution, and performed binding studies with DNA and protein targets. CS-ROSETTA models indicate that the Tfg1 and Tfg2 C-terminal domains have winged-helix architectures, similar to the human homologs. We showed that both Tfg1 and Tfg2 CTDs interact with double-stranded DNA oligonucleotides, and mapped the DNA binding interfaces using solution NMR. Tfg1-CTD, but not Tfg2-CTD, also binds to yeast FCP1, an RNA polymerase II-specific phosphatase, and we delineated the interaction surface with the CTD of FCP1. Our results provide insights into the structural basis of yeast TFIIF function and the differential roles of Tfg1 and Tfg2 subunits during transcription.
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Affiliation(s)
- Adina M Kilpatrick
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15260
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17
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Wostenberg C, Kumar S, Noid WG, Showalter SA. Atomistic Simulations Reveal Structural Disorder in the RAP74-FCP1 Complex. J Phys Chem B 2011; 115:13731-9. [DOI: 10.1021/jp208008m] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Christopher Wostenberg
- Department of Chemistry, The Pennsylvania State University, 104 Chemistry Building, University Park, Pennsylvania 16802, United States
| | - Sushant Kumar
- Huck Insitutes for the Life Sciences, The Pennsylvania State University, Pennsylvania 16802, United States
| | - William G. Noid
- Department of Chemistry, The Pennsylvania State University, 104 Chemistry Building, University Park, Pennsylvania 16802, United States
| | - Scott A. Showalter
- Department of Chemistry, The Pennsylvania State University, 104 Chemistry Building, University Park, Pennsylvania 16802, United States
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18
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Lawrence CW, Bonny A, Showalter SA. The disordered C-terminus of the RNA polymerase II phosphatase FCP1 is partially helical in the unbound state. Biochem Biophys Res Commun 2011; 410:461-5. [PMID: 21672523 DOI: 10.1016/j.bbrc.2011.05.160] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Accepted: 05/31/2011] [Indexed: 11/26/2022]
Abstract
Intrinsically disordered proteins (IDPs) lack unique 3D structures under native conditions and yet retain critical functions. Recycling of RNA Polymerase II after transcription is promoted by an interaction between the winged helix domain of RAP74, a component of the general transcription factor IIF (TFIIF), and the C-terminus of the TFIIF-associating CTD phosphatase (FCP1). Sixteen residues from the C-terminus of FCP1 form an α-helix in the complex, but the protein is otherwise agreed in the literature to be intrinsically disordered. Here we show through CD and recently developed carbon-detected NMR that, although FCP1 is intrinsically disordered, the above 16 residues composing the RAP74 binding surface form nascent α-helical structure in the unbound state. We further show retention of general FCP1 disorder and the nascent helical content in HeLa extract, establishing cellular relevance. The conformational bias observed leads to a mechanistic proposal for FCP1's transition from a disordered ensemble to an ordered conformation upon binding.
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Affiliation(s)
- Chad W Lawrence
- Department of Chemistry, The Pennsylvania State University, 104 Chemistry Building, University Park, PA 16802, USA.
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19
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Eichner J, Chen HT, Warfield L, Hahn S. Position of the general transcription factor TFIIF within the RNA polymerase II transcription preinitiation complex. EMBO J 2009; 29:706-16. [PMID: 20033062 DOI: 10.1038/emboj.2009.386] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2009] [Accepted: 12/01/2009] [Indexed: 11/09/2022] Open
Abstract
The RNA polymerase (pol) II general transcription factor TFIIF functions at several steps in transcription initiation including preinitiation complex (PIC) formation and start site selection. We find that two structured TFIIF domains bind Pol II at separate locations far from the active site with the TFIIF dimerization domain on the Pol II lobe and the winged helix domain of the TFIIF small subunit Tfg2 above the Pol II protrusion where it may interact with upstream promoter DNA. Binding of the winged helix to the protrusion is PIC specific. Anchoring of these two structured TFIIF domains at separate sites locates an essential and unstructured region of Tfg2 near the Pol II active site cleft where it may interact with flexible regions of Pol II and the general factor TFIIB to promote initiation and start site selection. Consistent with this mechanism, mutations far from the enzyme active site, which alter the binding of either structured TFIIF domains to Pol II, have similar defects in transcription start site usage.
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Affiliation(s)
- Jesse Eichner
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
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20
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Showalter SA. NMR assignment of the intrinsically disordered C-terminal region of Homo sapiens FCP1 in the unbound state. BIOMOLECULAR NMR ASSIGNMENTS 2009; 3:179-181. [PMID: 19888685 DOI: 10.1007/s12104-009-9169-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2009] [Accepted: 06/03/2009] [Indexed: 05/28/2023]
Abstract
The phosphorylation state of the RNA polymerase II C-terminal repeat domain (CTD) regulates progression through the mRNA biogenesis cycle. Termination of transcription and recycling of RNA polymerase II is promoted by an interaction between the general transcription factor IIF (TFIIF) and the TFIIF-associating CTD phosphatase (FCP1). The acidic C-terminal region of FCP1 is disordered in the free state, but adopts an alpha-helical conformation upon binding to the heavy chain of TFIIF. Here we report (1)H, (13)C, and (15)N resonance assignments for the intrinsically disordered unbound form of human C-terminal FCP1 (residues 879-961). The use of recently developed (13)C direct detected "protonless" NMR experiments allowed the nearly complete assignment of FCP1 reported here and is likely to be a generally effective strategy for the chemical shift assignment of disordered proteins.
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Affiliation(s)
- Scott A Showalter
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA.
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21
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The RNA Pol II CTD phosphatase Fcp1 is essential for normal development in Drosophila melanogaster. Gene 2009; 446:58-67. [PMID: 19632310 DOI: 10.1016/j.gene.2009.07.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2008] [Revised: 07/09/2009] [Accepted: 07/17/2009] [Indexed: 11/23/2022]
Abstract
The reversible phosphorylation-dephosphorylation of RNA polymerase II (Pol II) large subunit carboxyl terminal domain (CTD) during transcription cycles in eukaryotic cells generates signals for the steps of RNA synthesis and maturation. The major phosphatase specific for CTD dephosphorylation from yeast to mammals is the TFIIF-interacting CTD-phosphatase, Fcp1. We report here on the in vivo analysis of Fcp1 function in Drosophila using transgenic lines in which the phosphatase production is misregulated. Fcp1 function is essential throughout Drosophila development and ectopic up- or downregulation of fcp1 results in lethality. The fly Fcp1 binds to specific regions of the polytene chromosomes at many sites colocalized with Pol II. In accord with the strong evolutional conservation of Fcp1: (1) the Xenopus fcp1 can substitute the fly fcp1 function, (2) similarly to its S. pombe homologue, Drosophila melanogaster (Dm)Fcp1 interacts with the RPB4 subunit of Pol II, and (3) transient expression of DmFcp1 has a negative effect on transcription in mammalian cells. The in vivo experimental system described here suggests that fly Fcp1 is associated with the transcription engaged Pol II and offers versatile possibilities for studying this evolutionary conserved essential enzyme.
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22
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Yang A, Abbott KL, Desjardins A, Di Lello P, Omichinski JG, Legault P. NMR Structure of a Complex Formed by the Carboxyl-Terminal Domain of Human RAP74 and a Phosphorylated Peptide from the Central Domain of the FCP1 Phosphatase. Biochemistry 2009; 48:1964-74. [DOI: 10.1021/bi801549m] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ao Yang
- Département de Biochimie, Université de Montréal, C.P. 6128, Succursale Centre-Ville, Montréal, QC, Canada H3C 3J7, and Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602
| | - Karen L. Abbott
- Département de Biochimie, Université de Montréal, C.P. 6128, Succursale Centre-Ville, Montréal, QC, Canada H3C 3J7, and Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602
| | - Alexandre Desjardins
- Département de Biochimie, Université de Montréal, C.P. 6128, Succursale Centre-Ville, Montréal, QC, Canada H3C 3J7, and Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602
| | - Paola Di Lello
- Département de Biochimie, Université de Montréal, C.P. 6128, Succursale Centre-Ville, Montréal, QC, Canada H3C 3J7, and Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602
| | - James G. Omichinski
- Département de Biochimie, Université de Montréal, C.P. 6128, Succursale Centre-Ville, Montréal, QC, Canada H3C 3J7, and Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602
| | - Pascale Legault
- Département de Biochimie, Université de Montréal, C.P. 6128, Succursale Centre-Ville, Montréal, QC, Canada H3C 3J7, and Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602
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23
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Oyama T, Oka H, Mayanagi K, Shirai T, Matoba K, Fujikane R, Ishino Y, Morikawa K. Atomic structures and functional implications of the archaeal RecQ-like helicase Hjm. BMC STRUCTURAL BIOLOGY 2009; 9:2. [PMID: 19159486 PMCID: PMC2636818 DOI: 10.1186/1472-6807-9-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/06/2008] [Accepted: 01/22/2009] [Indexed: 11/10/2022]
Abstract
BACKGROUND Pyrococcus furiosus Hjm (PfuHjm) is a structure-specific DNA helicase that was originally identified by in vitro screening for Holliday junction migration activity. It belongs to helicase superfamily 2, and shares homology with the human DNA polymerase Theta (PolTheta), HEL308, and Drosophila Mus308 proteins, which are involved in DNA repair. Previous biochemical and genetic analyses revealed that PfuHjm preferentially binds to fork-related Y-structured DNAs and unwinds their double-stranded regions, suggesting that this helicase is a functional counterpart of the bacterial RecQ helicase, which is essential for genome maintenance. Elucidation of the DNA unwinding and translocation mechanisms by PfuHjm will require its three-dimensional structure at atomic resolution. RESULTS We determined the crystal structures of PfuHjm, in two apo-states and two nucleotide bound forms, at resolutions of 2.0-2.7 A. The overall structures and the local conformations around the nucleotide binding sites are almost the same, including the side-chain conformations, irrespective of the nucleotide-binding states. The architecture of Hjm was similar to that of Archaeoglobus fulgidus Hel308 complexed with DNA. An Hjm-DNA complex model, constructed by fitting the five domains of Hjm onto the corresponding Hel308 domains, indicated that the interaction of Hjm with DNA is similar to that of Hel308. Notably, sulphate ions bound to Hjm lie on the putative DNA binding surfaces. Electron microscopic analysis of an Hjm-DNA complex revealed substantial flexibility of the double stranded region of DNA, presumably due to particularly weak protein-DNA interactions. Our present structures allowed reasonable homology model building of the helicase region of human PolTheta, indicating the strong conformational conservation between archaea and eukarya. CONCLUSION The detailed comparison between our DNA-free PfuHjm structure and the structure of Hel308 complexed with DNA suggests similar DNA unwinding and translocation mechanisms, which could be generalized to all of the members in the same family. Structural comparison also implied a minor rearrangement of the five domains during DNA unwinding reaction. The unexpected small contact between the DNA duplex region and the enzyme appears to be advantageous for processive helicase activity.
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Affiliation(s)
- Takuji Oyama
- The Takara Bio Endowed Division, Institute for Protein Research, Osaka University, Open Laboratories of Advanced Bioscience and Biotechnology (OLABB), 6-2-3 Furuedai, Suita, Osaka 565-0874, Japan
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24
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Lavery DN, McEwan IJ. Functional characterization of the native NH2-terminal transactivation domain of the human androgen receptor: binding kinetics for interactions with TFIIF and SRC-1a. Biochemistry 2008; 47:3352-9. [PMID: 18284209 DOI: 10.1021/bi702220p] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The androgen receptor (AR) is a ligand-activated transcription factor that mediates the actions of the steroid hormones testosterone and dihydrotestosterone at the level of gene transcription. The main transactivation function is modular in structure, maps to the N-terminal domain (NTD), and is termed AF1. This region of the AR is structurally flexible and functions in multiple protein-protein interactions with coregulatory proteins and components of the general transcription machinery. Using surface plasmon resonance, the binding kinetics for the interaction of AR-AF1 with the large subunit of the general transcription factor TFIIF, termed RAP74, and the coactivator SRC-1a were measured. AR-AF1 interacts with both the NTD and CTD of RAP74 and the CTD of SRC-1a. The dissociation constants ( Kd) for the binding of polypeptides derived from RAP74 are in the submicromolar range, while a peptide from SRC-1a bound with a Kd of 14 microM. Significantly, the individual NTD and CTD of RAP74 interacted with AR-AF1 with distinct binding kinetics, with the NTD exhibiting slower on and off rates. TFIIF is involved in transcription initiation and elongation, and the CTD of RAP74 binds to the RNA polymerase II enzyme, the general transcription factor TFIIB, and a CTD phosphatase, FCP1. We have mutated hydrophobic residues in the RAP74-CTD structure to disrupt secondary structure elements and show that binding of AR-AF1 depends upon helix 3 in the winged-helix domain of the RAP74-CTD polypeptide. Altogether, a model is suggested for AR-AF1-dependent transactivation of receptor-target genes.
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Affiliation(s)
- Derek N Lavery
- School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, United Kingdom
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25
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Carlier L, Couprie J, le Maire A, Guilhaudis L, Milazzo-Segalas I, Courçon M, Moutiez M, Gondry M, Davoust D, Gilquin B, Zinn-Justin S. Solution structure of the region 51-160 of human KIN17 reveals an atypical winged helix domain. Protein Sci 2008; 16:2750-5. [PMID: 18029424 DOI: 10.1110/ps.073079107] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Human KIN17 is a 45-kDa eukaryotic DNA- and RNA-binding protein that plays an important role in nuclear metabolism and in particular in the general response to genotoxics. Its amino acids sequence contains a zinc finger motif (residues 28-50) within a 30-kDa N-terminal region conserved from yeast to human, and a 15-kDa C-terminal tandem of SH3-like subdomains (residues 268-393) only found in higher eukaryotes. Here we report the solution structure of the region 51-160 of human KIN17. We show that this fragment folds into a three-alpha-helix bundle packed against a three-stranded beta-sheet. It belongs to the winged helix (WH) family. Structural comparison with analogous WH domains reveals that KIN17 WH module presents an additional and highly conserved 3(10)-helix. Moreover, KIN17 WH helix H3 is not positively charged as in classical DNA-binding WH domains. Thus, human KIN17 region 51-160 might rather be involved in protein-protein interaction through its conserved surface centered on the 3(10)-helix.
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Affiliation(s)
- Ludovic Carlier
- Equipe de Chimie Organique et Biologie Structurale, IFRMP 23, CNRS UMR 6014, Université de Rouen, 76821 Mont-Saint-Aignan, France
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26
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Choudhry MA, Ball A, McEwan IJ. The role of the general transcription factor IIF in androgen receptor-dependent transcription. Mol Endocrinol 2006; 20:2052-61. [PMID: 16645039 DOI: 10.1210/me.2005-0486] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The androgen receptor (AR) is a member of the steroid receptor subfamily of nuclear receptors and is important for normal male sexual differentiation and fertility. The major transactivation function of the AR, termed activation function 1 (AF1), is modular in structure and has been mapped to the N terminus of the protein. To understand better the mechanisms whereby the AR activates transcription, we have established a novel cell-free transcription assay. This is based on the use of a dual reporter gene template, containing promoter proximal and distal G-less cassettes, which result in different size transcripts that can be easily detected and quantified. The promoter proximal transcript gives an indication of transcription initiation and promoter escape, whereas the relative levels of the distal transcript indicate elongation efficiency. The AR-AF1-Lex protein enhanced production of both transcripts whereas, in the absence of DNA binding, the AF1 domain squelched both initiation and elongation. Mutations in the transactivation domain that impaired transactivation and/or binding of the general transcription factor IIF (TFIIF) were found to reduce the ability of AR-AF1 to squelch transcription. Addition of recombinant TFIIF reversed squelching of the promoter-proximal but not the -distal G-less transcript, whereas addition of TATA-binding protein failed to reverse squelching of either transcript. Taken together, these results demonstrate that the AR N-terminal transactivation function, AF1, has the potential to regulate transcription at both the level of initiation and elongation, and that interactions with TFIIF are important during preinitiation complex assembly/open complex formation and/or promoter escape.
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Affiliation(s)
- M Ansar Choudhry
- School of Medical Sciences, Institute of Medical Sciences Building, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, Scotland, United Kingdom
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27
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Meinhart A, Kamenski T, Hoeppner S, Baumli S, Cramer P. A structural perspective of CTD function. Genes Dev 2005; 19:1401-15. [PMID: 15964991 DOI: 10.1101/gad.1318105] [Citation(s) in RCA: 255] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The C-terminal domain (CTD) of RNA polymerase II (Pol II) integrates nuclear events by binding proteins involved in mRNA biogenesis. CTD-binding proteins recognize a specific CTD phosphorylation pattern, which changes during the transcription cycle, due to the action of CTD-modifying enzymes. Structural and functional studies of CTD-binding and -modifying proteins now reveal some of the mechanisms underlying CTD function. Proteins recognize CTD phosphorylation patterns either directly, by contacting phosphorylated residues, or indirectly, without contact to the phosphate. The catalytic mechanisms of CTD kinases and phosphatases are known, but the basis for CTD specificity of these enzymes remains to be understood.
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Affiliation(s)
- Anton Meinhart
- Department of Chemistry and Biochemistry, Gene Center, University of Munich (LMU), 81377 Munich, Germany
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28
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Sims RJ, Belotserkovskaya R, Reinberg D. Elongation by RNA polymerase II: the short and long of it. Genes Dev 2004; 18:2437-68. [PMID: 15489290 DOI: 10.1101/gad.1235904] [Citation(s) in RCA: 533] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Appreciable advances into the process of transcript elongation by RNA polymerase II (RNAP II) have identified this stage as a dynamic and highly regulated step of the transcription cycle. Here, we discuss the many factors that regulate the elongation stage of transcription. Our discussion includes the classical elongation factors that modulate the activity of RNAP II, and the more recently identified factors that facilitate elongation on chromatin templates. Additionally, we discuss the factors that associate with RNAP II, but do not modulate its catalytic activity. Elongation is highlighted as a central process that coordinates multiple stages in mRNA biogenesis and maturation.
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Affiliation(s)
- Robert J Sims
- Howard Hughes Medical Institute, Robert Wood Johnson Medical School, Piscataway, New Jersey 08854, USA
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29
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Abstract
New structural studies of RNA polymerase II (Pol II) complexes mark the beginning of a detailed mechanistic analysis of the eukaryotic mRNA transcription cycle. Crystallographic models of the complete Pol II, together with new biochemical and electron microscopic data, give insights into transcription initiation. The first X-ray analysis of a Pol II complex with a transcription factor, the elongation factor TFIIS, supports the idea that the polymerase has a 'tunable' active site that switches between mRNA synthesis and cleavage. The new studies also show that domains of transcription factors can enter polymerase openings, to modulate function during transcription.
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Affiliation(s)
- Patrick Cramer
- Institute of Biochemistry and Gene Center, University of Munich, Feodor-Lynen-Str. 25, 81377 Munich, Germany.
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30
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Kamenski T, Heilmeier S, Meinhart A, Cramer P. Structure and mechanism of RNA polymerase II CTD phosphatases. Mol Cell 2004; 15:399-407. [PMID: 15304220 DOI: 10.1016/j.molcel.2004.06.035] [Citation(s) in RCA: 108] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2004] [Revised: 05/21/2004] [Accepted: 05/26/2004] [Indexed: 11/15/2022]
Abstract
Recycling of RNA polymerase II (Pol II) after transcription requires dephosphorylation of the polymerase C-terminal domain (CTD) by the phosphatase Fcp1. We report the X-ray structure of the small CTD phosphatase Scp1, which is homologous to the Fcp1 catalytic domain. The structure shows a core fold and an active center similar to those of phosphotransferases and phosphohydrolases that solely share a DXDX(V/T) signature motif with Fcp1/Scp1. We demonstrate that the first aspartate in the signature motif undergoes metal-assisted phosphorylation during catalysis, resulting in a phosphoaspartate intermediate that was structurally mimicked with the inhibitor beryllofluoride. Specificity may result from CTD binding to a conserved hydrophobic pocket between the active site and an insertion domain that is unique to Fcp1/Scp1. Fcp1 specificity may additionally arise from phosphatase recruitment near the CTD via the Pol II subcomplex Rpb4/7, which is shown to be required for binding of Fcp1 to the polymerase in vitro.
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Affiliation(s)
- Tomislav Kamenski
- Department of Chemistry and Biochemistry, Gene Center, University of Munich, Feodor-Lynen-Str. 25, 81377 Munich, Germany
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31
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Fuxreiter M, Simon I, Friedrich P, Tompa P. Preformed structural elements feature in partner recognition by intrinsically unstructured proteins. J Mol Biol 2004; 338:1015-26. [PMID: 15111064 DOI: 10.1016/j.jmb.2004.03.017] [Citation(s) in RCA: 423] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2003] [Revised: 03/02/2004] [Accepted: 03/02/2004] [Indexed: 12/25/2022]
Abstract
Intrinsically unstructured proteins (IUPs) are devoid of extensive structural order but often display signs of local and limited residual structure. To explain their effective functioning, we reasoned that such residual structure can be crucial in their interactions with their structured partner(s) in a way that preformed structural elements presage their final conformational state. To check this assumption, a database of 24 IUPs with known 3D structures in the bound state has been assembled and the distribution of secondary structure elements and backbone torsion angles have been analysed. The high proportion of residues in coil conformation and with phi, psi angles in the disallowed regions of the Ramachandran map compared to the reference set of globular proteins shows that IUPs are not fully ordered even in their bound form. To probe the effect of partner proteins on IUP folding, inherent conformational preferences of IUP sequences have been assessed by secondary structure predictions using the GOR, ALB and PROF algorithms. The accuracy of predicting secondary structure elements of IUPs is similar to that of their partner proteins and is significantly higher than the corresponding values for random sequences. We propose that strong conformational preferences mark regions in IUPs (mostly helices), which correspond to their final structural state, while regions with weak conformational preferences represent flexible linkers between them. In our interpretation, preformed elements could serve as initial contact points, the binding of which facilitates the reeling of the flexible regions onto the template. This finding implies that IUPs draw a functional advantage from preformed structural elements, as they enable their facile, kinetically and energetically less demanding, interaction with their physiological partner.
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Affiliation(s)
- Monika Fuxreiter
- Institute of Enzymology, Biological Research Center, Hungarian Academy of Sciences, Budapest, Hungary
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32
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Hahn S. Structure and mechanism of the RNA polymerase II transcription machinery. Nat Struct Mol Biol 2004; 11:394-403. [PMID: 15114340 PMCID: PMC1189732 DOI: 10.1038/nsmb763] [Citation(s) in RCA: 352] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2003] [Accepted: 03/22/2004] [Indexed: 11/09/2022]
Abstract
Advances in structure determination of the bacterial and eukaryotic transcription machinery have led to a marked increase in the understanding of the mechanism of transcription. Models for the specific assembly of the RNA polymerase II transcription machinery at a promoter, conformational changes that occur during initiation of transcription, and the mechanism of initiation are discussed in light of recent developments.
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Affiliation(s)
- Steven Hahn
- Fred Hutchinson Cancer Research Center and Howard Hughes Medical Institute, 1100 Fairview Ave N., A1-162, Seattle, Washington 98109, USA.
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33
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Harris R, Esposito D, Sankar A, Maman JD, Hinks JA, Pearl LH, Driscoll PC. The 3D solution structure of the C-terminal region of Ku86 (Ku86CTR). J Mol Biol 2004; 335:573-82. [PMID: 14672664 DOI: 10.1016/j.jmb.2003.10.047] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
In eukaryotes the non-homologous end-joining repair of double strand breaks in DNA is executed by a series of proteins that bring about the synapsis, preparation and ligation of the broken DNA ends. The mechanism of this process appears to be initiated by the obligate heterodimer (Ku70/Ku86) protein complex Ku that has affinity for DNA ends. Ku then recruits the DNA-dependent protein kinase catalytic subunit (DNA-PKcs). The three-dimensional structures of the major part of the Ku heterodimer, representing the DNA-binding core, both free and bound to DNA are known from X-ray crystallography. However, these structures lack a region of ca 190 residues from the C-terminal region (CTR) of the Ku86 subunit (also known as Lupus Ku autoantigen p86, Ku80, or XRCC5) that includes the extreme C-terminal tail that is reported to be sufficient for DNA-PKcs-binding. We have examined the structural characteristics of the Ku86CTR protein expressed in bacteria. By deletion mutagenesis and heteronuclear NMR spectroscopy we localised a globular domain consisting of residues 592-709. Constructs comprising additional residues either to the N-terminal side (residues 543-709), or the C-terminal side (residues 592-732), which includes the putative DNA-PKcs-binding motif, yielded NMR spectra consistent with these extra regions lacking ordered structure. The three-dimensional solution structure of the core globular domain of the C-terminal region of Ku86 (Ku86CTR(592-709)) has been determined using heteronuclear NMR spectroscopy and dynamical simulated annealing using structural restraints from nuclear Overhauser effect spectroscopy, and scalar and residual dipolar couplings. The polypeptide fold comprises six regions of alpha-helical secondary structure that has an overall superhelical topology remotely homologous to the MIF4G homology domain of the human nuclear cap binding protein 80 kDa subunit and the VHS domain of the Drosophila protein Hrs, though strict analysis of the structures suggests that these domains are not functionally related. Two prominent hydrophobic pockets in the gap between helices alpha2 and alpha4 suggest a potential ligand-binding characteristic for this globular domain.
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Affiliation(s)
- Richard Harris
- Bloomsbury Centre for Structural Biology, University College London, Gower Street, London WC1E 6BT, UK
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34
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Meinhart A, Blobel J, Cramer P. An Extended Winged Helix Domain in General Transcription Factor E/IIEα. J Biol Chem 2003; 278:48267-74. [PMID: 13679366 DOI: 10.1074/jbc.m307874200] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Initiation of eukaryotic mRNA transcription requires melting of promoter DNA with the help of the general transcription factors TFIIE and TFIIH. Here we define a conserved and functionally essential N-terminal domain in TFE, the archaeal homolog of the large TFIIE subunit alpha. X-ray crystallography shows that this TFE domain adopts a winged helix-turn-helix (winged helix) fold, extended by specific alpha-helices at the N and C termini. Although the winged helix fold is often found in DNA-binding proteins, we show that TFE is not a typical DNA-binding winged helix protein, because its putative DNA-binding face shows a negatively charged groove and an unusually long wing, and because the domain lacks DNA-binding activity in vitro. The groove and a conserved hydrophobic surface patch on the additional N-terminal alpha-helix may, however, allow for interactions with other general transcription factors and RNA polymerase. Homology modeling shows that the TFE domain is conserved in TFIIE alpha, including the potential functional surfaces.
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MESH Headings
- Amino Acid Sequence
- Cloning, Molecular
- Crystallography, X-Ray
- DNA/chemistry
- DNA/metabolism
- DNA-Directed RNA Polymerases/chemistry
- Models, Molecular
- Molecular Sequence Data
- Mutagenesis, Site-Directed
- Promoter Regions, Genetic
- Protein Binding
- Protein Conformation
- Protein Folding
- Protein Structure, Secondary
- Protein Structure, Tertiary
- RNA, Messenger/metabolism
- Selenomethionine/metabolism
- Sequence Homology, Amino Acid
- Sigma Factor/metabolism
- Sulfolobus/metabolism
- Transcription Factors, TFII/chemistry
- Transcription Factors, TFII/metabolism
- Transcription, Genetic
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Affiliation(s)
- Anton Meinhart
- Institute of Biochemistry, Gene Center, University of Munich, Feodor-Lynen-Strasse 25, 81377 Munich, Germany
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