1
|
Götz M, Barth A, Bohr SSR, Börner R, Chen J, Cordes T, Erie DA, Gebhardt C, Hadzic MCAS, Hamilton GL, Hatzakis NS, Hugel T, Kisley L, Lamb DC, de Lannoy C, Mahn C, Dunukara D, de Ridder D, Sanabria H, Schimpf J, Seidel CAM, Sigel RKO, Sletfjerding MB, Thomsen J, Vollmar L, Wanninger S, Weninger KR, Xu P, Schmid S. Reply to: On the statistical foundation of a recent single molecule FRET benchmark. Nat Commun 2024; 15:3626. [PMID: 38688911 PMCID: PMC11061175 DOI: 10.1038/s41467-024-47734-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 04/09/2024] [Indexed: 05/02/2024] Open
Affiliation(s)
- Markus Götz
- PicoQuant GmbH, Rudower Chaussee 29, 12489, Berlin, Germany.
| | - Anders Barth
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Van der Maasweg 9, 2629, HZ Delft, The Netherlands
| | - Søren S-R Bohr
- Department of Chemistry, University of Copenhagen, 2100, Copenhagen, Denmark
- Novo Nordisk Center for optimised oligo escape and control of disease University of Copenhagen, 2100 Novo Nordisk Foundation Centre for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, 2100, Copenhagen, Denmark
| | - Richard Börner
- Department of Chemistry, University of Zurich, 8057, Zurich, Switzerland
- Laserinstitut Hochschule Mittweida, University of Applied Sciences Mittweida, 09648, Mittweida, Germany
| | - Jixin Chen
- Department of Chemistry and Biochemistry, Ohio University, Athens, OH, USA
| | - Thorben Cordes
- Physical and Synthetic Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, Großhadernerstr. 2-4, 82152, Planegg-Martinsried, Germany
| | - Dorothy A Erie
- Department of Chemistry, University of North Carolina, Chapel Hill, NC, 27599, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Christian Gebhardt
- Physical and Synthetic Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, Großhadernerstr. 2-4, 82152, Planegg-Martinsried, Germany
| | | | - George L Hamilton
- Department of Physics and Astronomy, Clemson University, Clemson, SC, 29634, USA
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY, USA
| | - Nikos S Hatzakis
- Department of Chemistry, University of Copenhagen, 2100, Copenhagen, Denmark
- Novo Nordisk Center for optimised oligo escape and control of disease University of Copenhagen, 2100 Novo Nordisk Foundation Centre for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, 2100, Copenhagen, Denmark
| | - Thorsten Hugel
- Institute of Physical Chemistry, University of Freiburg, Freiburg, Germany
- Signalling Research Centers BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
| | - Lydia Kisley
- Department of Physics, Case Western Reserve University, Cleveland, OH, USA
- Department of Chemistry, Case Western Reserve University, Cleveland, OH, USA
| | - Don C Lamb
- Department of Chemistry and Center for Nano Science (CeNS), Ludwig Maximilians-Universität München, Butenandtstraße 5-13, 81377, München, Germany
| | - Carlos de Lannoy
- Bioinformatics Group, Wageningen University, Droevendaalsesteeg 1, 6708PB, Wageningen, The Netherlands
| | - Chelsea Mahn
- Department of Physics, North Carolina State University, Raleigh, NC, 27695, USA
| | - Dushani Dunukara
- Department of Physics, Case Western Reserve University, Cleveland, OH, USA
| | - Dick de Ridder
- Bioinformatics Group, Wageningen University, Droevendaalsesteeg 1, 6708PB, Wageningen, The Netherlands
| | - Hugo Sanabria
- Department of Physics and Astronomy, Clemson University, Clemson, SC, 29634, USA
| | - Julia Schimpf
- Institute of Physical Chemistry, University of Freiburg, Freiburg, Germany
- Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, Freiburg, Germany
| | - Claus A M Seidel
- Institut für Physikalische Chemie, Lehrstuhl für Molekulare Physikalische Chemie, Heinrich-Heine-Universität, Universitätsstr. 1, 40225, Düsseldorf, Germany
| | - Roland K O Sigel
- Department of Chemistry, University of Zurich, 8057, Zurich, Switzerland
| | - Magnus B Sletfjerding
- Department of Chemistry, University of Copenhagen, 2100, Copenhagen, Denmark
- Novo Nordisk Center for optimised oligo escape and control of disease University of Copenhagen, 2100 Novo Nordisk Foundation Centre for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, 2100, Copenhagen, Denmark
| | - Johannes Thomsen
- Department of Chemistry, University of Copenhagen, 2100, Copenhagen, Denmark
- Novo Nordisk Center for optimised oligo escape and control of disease University of Copenhagen, 2100 Novo Nordisk Foundation Centre for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, 2100, Copenhagen, Denmark
| | - Leonie Vollmar
- Institute of Physical Chemistry, University of Freiburg, Freiburg, Germany
- Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, Freiburg, Germany
| | - Simon Wanninger
- Department of Chemistry and Center for Nano Science (CeNS), Ludwig Maximilians-Universität München, Butenandtstraße 5-13, 81377, München, Germany
| | - Keith R Weninger
- Department of Physics, North Carolina State University, Raleigh, NC, 27695, USA
| | - Pengning Xu
- Department of Physics, North Carolina State University, Raleigh, NC, 27695, USA
| | - Sonja Schmid
- NanoDynamicsLab, Laboratory of Biophysics, Wageningen University, Stippeneng 4, 6708WE, Wageningen, The Netherlands.
- Department of Chemistry, University of Basel, Basel, Switzerland.
| |
Collapse
|
2
|
Satusky MJ, Johnson CV, Erie DA. Rapid, inexpensive, sequence-independent fluorescent labeling of phosphorothioate DNA. Biophys J 2023; 122:1211-1218. [PMID: 36793216 PMCID: PMC10111259 DOI: 10.1016/j.bpj.2023.02.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 01/23/2023] [Accepted: 02/10/2023] [Indexed: 02/16/2023] Open
Abstract
Fluorescently labeled oligonucleotides are powerful tools for characterizing DNA processes; however, their use is limited by the cost and sequence requirements of current labeling technologies. Here, we develop an easy, inexpensive, and sequence-independent method for site-specifically labeling DNA oligonucleotides. We utilize commercially synthesized oligonucleotides containing phosphorothioate diester(s) in which a nonbridging oxygen is replaced with a sulfur (PS-DNA). The increased nucleophilicity of the thiophosphoryl sulfur relative to the phosphoryl oxygen permits selective reactivity with iodoacetamide compounds. As such, we leverage a long-existing bifunctional linker, N,N'-bis(α-iodoacetyl)-2-2'-dithiobis(ethylamine) (BIDBE), that reacts with PS-DNAs to leave a free thiol, allowing conjugation of the wide variety of commercial maleimide-functionalized compounds. We optimized BIDBE synthesis and its attachment to PS-DNA and then fluorescently labeled the BIDBE-PS-DNA using standard protocols for labeling cysteines. We purified the individual epimers, and using single-molecule Förster resonance energy transfer (FRET), we show that the FRET efficiency is independent of the epimeric attachment. Subsequently, we demonstrate that an epimeric mixture of double-labeled Holliday junctions (HJs) can be used to characterize their conformational properties in the absence and presence of the structure-specific endonuclease Drosophila melanogaster Gen. Finally, we use a biochemical activity assay to show that this double-labeled HJ is functional for cleavage by Gen and that the double-labeled HJ allows multiple DNA species to be identified in a single experiment. In conclusion, our results indicate that dye-labeled BIDBE-PS-DNAs are comparable to commercially labeled DNAs at a significantly reduced cost. Notably, this technology could be applied to other maleimide-functionalized compounds, such as spin labels, biotin, and proteins. The sequence independence of labeling, coupled with its ease and low cost, enables unrestricted exploration of dye placement and choice, providing the potential for creation of differentially labeled DNA libraries and opening previously inaccessible experimental avenues.
Collapse
Affiliation(s)
- Matthew J Satusky
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina
| | - Caitlin V Johnson
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina
| | - Dorothy A Erie
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina; Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina.
| |
Collapse
|
3
|
Satusky MJ, Wilkins H, Hutson B, Nasiri M, King D, Erie DA, Freeman TC. CUREing biochemistry lab monotony. J Chem Educ 2022; 99:3888-3898. [PMID: 38628949 PMCID: PMC11019968 DOI: 10.1021/acs.jchemed.2c00357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/19/2024]
Abstract
Undergraduate research experience is critical to success in post-graduate research settings. The recent movement away from "cookbook" style labs to course-based undergraduate research experiences (CUREs) in undergraduate laboratories has allowed universities to provide inclusive research experience while bypassing the limitations of extracurricular apprenticeships. This paper describes an upper-level biochemistry CURE designed to provide students with an introductory experience to graduate-level research by studying a suspected DNA helicase. This CURE is designed to span multiple semesters, where each student cohort builds upon the work of previous semesters. Pre- and post-course surveys were employed to assess student confidence in bench skills, perceptions of the course, and project ownership. The results show that the incorporation of lab meeting-style recitations and poster presentations led to higher project ownership, while overcoming troubleshooting was a significant challenge. Furthermore, confidence in every experimental technique increased significantly in all but one instance. Based on these results, this CURE is providing students with a realistic experience in graduate-level research.
Collapse
Affiliation(s)
- Matthew J Satusky
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Hunter Wilkins
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Bryant Hutson
- Office of Institutional Research and Assessment, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Mahfuz Nasiri
- Office of Institutional Research and Assessment, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Dillon King
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599, USA
- Nicholas School of the Environment, Duke University, Durham, NC 27710, USA
| | - Dorothy A. Erie
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Thomas C. Freeman
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599, USA
| |
Collapse
|
4
|
Götz M, Barth A, Bohr SSR, Börner R, Chen J, Cordes T, Erie DA, Gebhardt C, Hadzic MCAS, Hamilton GL, Hatzakis NS, Hugel T, Kisley L, Lamb DC, de Lannoy C, Mahn C, Dunukara D, de Ridder D, Sanabria H, Schimpf J, Seidel CAM, Sigel RKO, Sletfjerding MB, Thomsen J, Vollmar L, Wanninger S, Weninger KR, Xu P, Schmid S. A blind benchmark of analysis tools to infer kinetic rate constants from single-molecule FRET trajectories. Nat Commun 2022. [PMID: 36104339 DOI: 10.1101/2021.11.23.469671v2.article-info] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/28/2023] Open
Abstract
Single-molecule FRET (smFRET) is a versatile technique to study the dynamics and function of biomolecules since it makes nanoscale movements detectable as fluorescence signals. The powerful ability to infer quantitative kinetic information from smFRET data is, however, complicated by experimental limitations. Diverse analysis tools have been developed to overcome these hurdles but a systematic comparison is lacking. Here, we report the results of a blind benchmark study assessing eleven analysis tools used to infer kinetic rate constants from smFRET trajectories. We test them against simulated and experimental data containing the most prominent difficulties encountered in analyzing smFRET experiments: different noise levels, varied model complexity, non-equilibrium dynamics, and kinetic heterogeneity. Our results highlight the current strengths and limitations in inferring kinetic information from smFRET trajectories. In addition, we formulate concrete recommendations and identify key targets for future developments, aimed to advance our understanding of biomolecular dynamics through quantitative experiment-derived models.
Collapse
Affiliation(s)
- Markus Götz
- Centre de Biologie Structurale, CNRS UMR 5048, INSERM U1054, Univ Montpellier, 60 rue de Navacelles, 34090, Montpellier, France.
- PicoQuant GmbH, Rudower Chaussee 29, 12489, Berlin, Germany.
| | - Anders Barth
- Institut für Physikalische Chemie, Lehrstuhl für Molekulare Physikalische Chemie, Heinrich-Heine-Universität, Universitätsstr. 1, 40225, Düsseldorf, Germany
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Van der Maasweg 9, 2629, HZ Delft, The Netherlands
| | - Søren S-R Bohr
- Department of Chemistry & Nano-science Center, University of Copenhagen, 2100, Copenhagen, Denmark
- Novo Nordisk Foundation Centre for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, 2100, Copenhagen, Denmark
| | - Richard Börner
- Department of Chemistry, University of Zurich, 8057, Zurich, Switzerland
- Laserinstitut Hochschule Mittweida, University of Applied Sciences Mittweida, 09648, Mittweida, Germany
| | - Jixin Chen
- Department of Chemistry and Biochemistry, Ohio University, Athens, OH, USA
| | - Thorben Cordes
- Physical and Synthetic Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, Großhadernerstr. 2-4, 82152, Planegg-Martinsried, Germany
| | - Dorothy A Erie
- Department of Chemistry, University of North Carolina, Chapel Hill, NC, 27599, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Christian Gebhardt
- Physical and Synthetic Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, Großhadernerstr. 2-4, 82152, Planegg-Martinsried, Germany
| | | | - George L Hamilton
- Department of Physics and Astronomy, Clemson University, Clemson, SC, 29634, USA
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY, 10016, USA
| | - Nikos S Hatzakis
- Department of Chemistry & Nano-science Center, University of Copenhagen, 2100, Copenhagen, Denmark
- Novo Nordisk Foundation Centre for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, 2100, Copenhagen, Denmark
| | - Thorsten Hugel
- Institute of Physical Chemistry, University of Freiburg, Freiburg, Germany
- Signalling Research Centers BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
| | - Lydia Kisley
- Department of Physics, Case Western Reserve University, Cleveland, OH, USA
- Department of Chemistry, Case Western Reserve University, Cleveland, OH, USA
| | - Don C Lamb
- Department of Chemistry and Center for Nano Science (CeNS), Ludwig Maximilians-Universität München, Butenandtstraße 5-13, 81377, München, Germany
| | - Carlos de Lannoy
- Bioinformatics Group, Wageningen University, Droevendaalsesteeg 1, 6708PB, Wageningen, The Netherlands
| | - Chelsea Mahn
- Department of Physics, North Carolina State University, Raleigh, NC, 27695, USA
| | - Dushani Dunukara
- Department of Physics, Case Western Reserve University, Cleveland, OH, USA
| | - Dick de Ridder
- Bioinformatics Group, Wageningen University, Droevendaalsesteeg 1, 6708PB, Wageningen, The Netherlands
| | - Hugo Sanabria
- Department of Physics and Astronomy, Clemson University, Clemson, SC, 29634, USA
| | - Julia Schimpf
- Institute of Physical Chemistry, University of Freiburg, Freiburg, Germany
- Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, Freiburg, Germany
| | - Claus A M Seidel
- Institut für Physikalische Chemie, Lehrstuhl für Molekulare Physikalische Chemie, Heinrich-Heine-Universität, Universitätsstr. 1, 40225, Düsseldorf, Germany
| | - Roland K O Sigel
- Department of Chemistry, University of Zurich, 8057, Zurich, Switzerland
| | - Magnus Berg Sletfjerding
- Department of Chemistry & Nano-science Center, University of Copenhagen, 2100, Copenhagen, Denmark
- Novo Nordisk Foundation Centre for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, 2100, Copenhagen, Denmark
| | - Johannes Thomsen
- Department of Chemistry & Nano-science Center, University of Copenhagen, 2100, Copenhagen, Denmark
- Novo Nordisk Foundation Centre for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, 2100, Copenhagen, Denmark
| | - Leonie Vollmar
- Institute of Physical Chemistry, University of Freiburg, Freiburg, Germany
- Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, Freiburg, Germany
| | - Simon Wanninger
- Department of Chemistry and Center for Nano Science (CeNS), Ludwig Maximilians-Universität München, Butenandtstraße 5-13, 81377, München, Germany
| | - Keith R Weninger
- Department of Physics, North Carolina State University, Raleigh, NC, 27695, USA
| | - Pengning Xu
- Department of Physics, North Carolina State University, Raleigh, NC, 27695, USA
| | - Sonja Schmid
- NanoDynamicsLab, Laboratory of Biophysics, Wageningen University, Stippeneng 4, 6708WE, Wageningen, The Netherlands.
| |
Collapse
|
5
|
Götz M, Barth A, Bohr SSR, Börner R, Chen J, Cordes T, Erie DA, Gebhardt C, Hadzic MCAS, Hamilton GL, Hatzakis NS, Hugel T, Kisley L, Lamb DC, de Lannoy C, Mahn C, Dunukara D, de Ridder D, Sanabria H, Schimpf J, Seidel CAM, Sigel RKO, Sletfjerding MB, Thomsen J, Vollmar L, Wanninger S, Weninger KR, Xu P, Schmid S. A blind benchmark of analysis tools to infer kinetic rate constants from single-molecule FRET trajectories. Nat Commun 2022; 13:5402. [PMID: 36104339 PMCID: PMC9474500 DOI: 10.1038/s41467-022-33023-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Accepted: 08/30/2022] [Indexed: 01/04/2023] Open
Abstract
Single-molecule FRET (smFRET) is a versatile technique to study the dynamics and function of biomolecules since it makes nanoscale movements detectable as fluorescence signals. The powerful ability to infer quantitative kinetic information from smFRET data is, however, complicated by experimental limitations. Diverse analysis tools have been developed to overcome these hurdles but a systematic comparison is lacking. Here, we report the results of a blind benchmark study assessing eleven analysis tools used to infer kinetic rate constants from smFRET trajectories. We test them against simulated and experimental data containing the most prominent difficulties encountered in analyzing smFRET experiments: different noise levels, varied model complexity, non-equilibrium dynamics, and kinetic heterogeneity. Our results highlight the current strengths and limitations in inferring kinetic information from smFRET trajectories. In addition, we formulate concrete recommendations and identify key targets for future developments, aimed to advance our understanding of biomolecular dynamics through quantitative experiment-derived models.
Collapse
Affiliation(s)
- Markus Götz
- Centre de Biologie Structurale, CNRS UMR 5048, INSERM U1054, Univ Montpellier, 60 rue de Navacelles, 34090, Montpellier, France.
- PicoQuant GmbH, Rudower Chaussee 29, 12489, Berlin, Germany.
| | - Anders Barth
- Institut für Physikalische Chemie, Lehrstuhl für Molekulare Physikalische Chemie, Heinrich-Heine-Universität, Universitätsstr. 1, 40225, Düsseldorf, Germany
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Van der Maasweg 9, 2629, HZ Delft, The Netherlands
| | - Søren S-R Bohr
- Department of Chemistry & Nano-science Center, University of Copenhagen, 2100, Copenhagen, Denmark
- Novo Nordisk Foundation Centre for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, 2100, Copenhagen, Denmark
| | - Richard Börner
- Department of Chemistry, University of Zurich, 8057, Zurich, Switzerland
- Laserinstitut Hochschule Mittweida, University of Applied Sciences Mittweida, 09648, Mittweida, Germany
| | - Jixin Chen
- Department of Chemistry and Biochemistry, Ohio University, Athens, OH, USA
| | - Thorben Cordes
- Physical and Synthetic Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, Großhadernerstr. 2-4, 82152, Planegg-Martinsried, Germany
| | - Dorothy A Erie
- Department of Chemistry, University of North Carolina, Chapel Hill, NC, 27599, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Christian Gebhardt
- Physical and Synthetic Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, Großhadernerstr. 2-4, 82152, Planegg-Martinsried, Germany
| | | | - George L Hamilton
- Department of Physics and Astronomy, Clemson University, Clemson, SC, 29634, USA
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY, 10016, USA
| | - Nikos S Hatzakis
- Department of Chemistry & Nano-science Center, University of Copenhagen, 2100, Copenhagen, Denmark
- Novo Nordisk Foundation Centre for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, 2100, Copenhagen, Denmark
| | - Thorsten Hugel
- Institute of Physical Chemistry, University of Freiburg, Freiburg, Germany
- Signalling Research Centers BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
| | - Lydia Kisley
- Department of Physics, Case Western Reserve University, Cleveland, OH, USA
- Department of Chemistry, Case Western Reserve University, Cleveland, OH, USA
| | - Don C Lamb
- Department of Chemistry and Center for Nano Science (CeNS), Ludwig Maximilians-Universität München, Butenandtstraße 5-13, 81377, München, Germany
| | - Carlos de Lannoy
- Bioinformatics Group, Wageningen University, Droevendaalsesteeg 1, 6708PB, Wageningen, The Netherlands
| | - Chelsea Mahn
- Department of Physics, North Carolina State University, Raleigh, NC, 27695, USA
| | - Dushani Dunukara
- Department of Physics, Case Western Reserve University, Cleveland, OH, USA
| | - Dick de Ridder
- Bioinformatics Group, Wageningen University, Droevendaalsesteeg 1, 6708PB, Wageningen, The Netherlands
| | - Hugo Sanabria
- Department of Physics and Astronomy, Clemson University, Clemson, SC, 29634, USA
| | - Julia Schimpf
- Institute of Physical Chemistry, University of Freiburg, Freiburg, Germany
- Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, Freiburg, Germany
| | - Claus A M Seidel
- Institut für Physikalische Chemie, Lehrstuhl für Molekulare Physikalische Chemie, Heinrich-Heine-Universität, Universitätsstr. 1, 40225, Düsseldorf, Germany
| | - Roland K O Sigel
- Department of Chemistry, University of Zurich, 8057, Zurich, Switzerland
| | - Magnus Berg Sletfjerding
- Department of Chemistry & Nano-science Center, University of Copenhagen, 2100, Copenhagen, Denmark
- Novo Nordisk Foundation Centre for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, 2100, Copenhagen, Denmark
| | - Johannes Thomsen
- Department of Chemistry & Nano-science Center, University of Copenhagen, 2100, Copenhagen, Denmark
- Novo Nordisk Foundation Centre for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, 2100, Copenhagen, Denmark
| | - Leonie Vollmar
- Institute of Physical Chemistry, University of Freiburg, Freiburg, Germany
- Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, Freiburg, Germany
| | - Simon Wanninger
- Department of Chemistry and Center for Nano Science (CeNS), Ludwig Maximilians-Universität München, Butenandtstraße 5-13, 81377, München, Germany
| | - Keith R Weninger
- Department of Physics, North Carolina State University, Raleigh, NC, 27695, USA
| | - Pengning Xu
- Department of Physics, North Carolina State University, Raleigh, NC, 27695, USA
| | - Sonja Schmid
- NanoDynamicsLab, Laboratory of Biophysics, Wageningen University, Stippeneng 4, 6708WE, Wageningen, The Netherlands.
| |
Collapse
|
6
|
Johnson CV, Erie DA. Probing the effect of mutations on the conformational landscape of DNA mismatch repair protein MutS. Biophys J 2022. [DOI: 10.1016/j.bpj.2021.11.2407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
|
7
|
You X, Casper CB, Lentz EE, Erie DA, Atkin JM. Fabrication of a Biocompatible Mica/Gold Surface for Tip-Enhanced Raman Spectroscopy. Chemphyschem 2020; 21:188-193. [PMID: 31912640 PMCID: PMC7027439 DOI: 10.1002/cphc.201901002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 11/24/2019] [Indexed: 11/29/2022]
Abstract
Tip‐enhanced Raman spectroscopy (TERS) is a promising technique for structural studies of biological systems and biomolecules, owing to its ability to provide a chemical fingerprint with sub‐diffraction‐limit spatial resolution. This application of TERS has thus far been limited, due to difficulties in generating high field enhancements while maintaining biocompatibility. The high sensitivity achievable through TERS arises from the excitation of a localized surface plasmon resonance in a noble metal atomic force microscope (AFM) tip, which in combination with a metallic surface can produce huge enhancements in the local optical field. However, metals have poor biocompatibility, potentially introducing difficulties in characterizing native structure and conformation in biomolecules, whereas biocompatible surfaces have weak optical field enhancements. Herein, a novel, biocompatible, highly enhancing surface is designed and fabricated based on few‐monolayer mica flakes, mechanically exfoliated on a metal surface. These surfaces allow the formation of coupled plasmon enhancements for TERS imaging, while maintaining the biocompatibility and atomic flatness of the mica surface for high resolution AFM. The capability of these substrates for TERS is confirmed numerically and experimentally. We demonstrate up to five orders of magnitude improvement in TERS signals over conventional mica surfaces, expanding the sensitivity of TERS to a wide range of non‐resonant biomolecules with weak Raman cross‐sections. The increase in sensitivity obtained through this approach also enables the collection of nanoscale spectra with short integration times, improving hyperspectral mapping for these applications. These mica/metal surfaces therefore have the potential to revolutionize spectromicroscopy of complex, heterogeneous biological systems such as DNA and protein complexes.
Collapse
Affiliation(s)
- Xiao You
- Department of Applied Physical Science, University of North Carolina at Chapel Hill, Caudill Labs, Chapel Hill, North Carolina, 27514, U.S.A
| | - Clayton B Casper
- Department of Chemistry, University of North Carolina at Chapel Hill, Caudill Labs, Chapel Hill, North Carolina, 27514, U.S.A
| | - Emily E Lentz
- Department of Chemistry, University of North Carolina at Chapel Hill, Caudill Labs, Chapel Hill, North Carolina, 27514, U.S.A
| | - Dorothy A Erie
- Department of Chemistry, University of North Carolina at Chapel Hill, Caudill Labs, Chapel Hill, North Carolina, 27514, U.S.A
| | - Joanna M Atkin
- Department of Chemistry, University of North Carolina at Chapel Hill, Caudill Labs, Chapel Hill, North Carolina, 27514, U.S.A
| |
Collapse
|
8
|
Andres SN, Li ZM, Erie DA, Williams RS. Correction: Ctp1 protein–DNA filaments promote DNA bridging and DNA double-strand break repair. J Biol Chem 2020; 295:896. [DOI: 10.1074/jbc.aac119.012364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
|
9
|
LeBlanc SJ, Gauer JW, Hao P, Case BC, Hingorani MM, Weninger KR, Erie DA. Coordinated protein and DNA conformational changes govern mismatch repair initiation by MutS. Nucleic Acids Res 2019; 46:10782-10795. [PMID: 30272207 PMCID: PMC6237781 DOI: 10.1093/nar/gky865] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 09/26/2018] [Indexed: 12/13/2022] Open
Abstract
MutS homologs identify base-pairing errors made in DNA during replication and initiate their repair. In the presence of adenosine triphosphate, MutS induces DNA bending upon mismatch recognition and subsequently undergoes conformational transitions that promote its interaction with MutL to signal repair. In the absence of MutL, these transitions lead to formation of a MutS mobile clamp that can move along the DNA. Previous single-molecule FRET (smFRET) studies characterized the dynamics of MutS DNA-binding domains during these transitions. Here, we use protein–DNA and DNA–DNA smFRET to monitor DNA conformational changes, and we use kinetic analyses to correlate DNA and protein conformational changes to one another and to the steps on the pathway to mobile clamp formation. The results reveal multiple sequential structural changes in both MutS and DNA, and they suggest that DNA dynamics play a critical role in the formation of the MutS mobile clamp. Taking these findings together with data from our previous studies, we propose a unified model of coordinated MutS and DNA conformational changes wherein initiation of mismatch repair is governed by a balance of DNA bending/unbending energetics and MutS conformational changes coupled to its nucleotide binding properties.
Collapse
Affiliation(s)
- Sharonda J LeBlanc
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.,Department of Physics, North Carolina State University, Raleigh, NC 27695, USA
| | - Jacob W Gauer
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Pengyu Hao
- Department of Physics, North Carolina State University, Raleigh, NC 27695, USA
| | - Brandon C Case
- Molecular Biology and Biochemistry Department, Wesleyan University, Middletown, CT 06459, USA
| | - Manju M Hingorani
- Molecular Biology and Biochemistry Department, Wesleyan University, Middletown, CT 06459, USA
| | - Keith R Weninger
- Department of Physics, North Carolina State University, Raleigh, NC 27695, USA
| | - Dorothy A Erie
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.,Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| |
Collapse
|
10
|
Qiu R, DeRocco VC, Harris C, Sharma A, Hingorani MM, Erie DA, Weninger KR. Large conformational changes in MutS during
DNA
scanning, mismatch recognition and repair signaling. EMBO J 2019; 38:38/4/e101518. [DOI: 10.15252/embj.2019101518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
|
11
|
LeBlanc SJ, Hao P, Hinds MA, Morgan AN, Gbozah K, Weninger KR, Erie DA. Investigating the Function of Mutl Conformational Changes in Mismatch Repair using smFRET. Biophys J 2019. [DOI: 10.1016/j.bpj.2018.11.311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
|
12
|
Biernat KA, Pellock SJ, Bhatt AP, Bivins MM, Walton WG, Tran BNT, Wei L, Snider MC, Cesmat AP, Tripathy A, Erie DA, Redinbo MR. Structure, function, and inhibition of drug reactivating human gut microbial β-glucuronidases. Sci Rep 2019; 9:825. [PMID: 30696850 PMCID: PMC6351562 DOI: 10.1038/s41598-018-36069-w] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 11/14/2018] [Indexed: 01/15/2023] Open
Abstract
Bacterial β-glucuronidase (GUS) enzymes cause drug toxicity by reversing Phase II glucuronidation in the gastrointestinal tract. While many human gut microbial GUS enzymes have been examined with model glucuronide substrates like p-nitrophenol-β-D-glucuronide (pNPG), the GUS orthologs that are most efficient at processing drug-glucuronides remain unclear. Here we present the crystal structures of GUS enzymes from human gut commensals Lactobacillus rhamnosus, Ruminococcus gnavus, and Faecalibacterium prausnitzii that possess an active site loop (Loop 1; L1) analogous to that found in E. coli GUS, which processes drug substrates. We also resolve the structure of the No Loop GUS from Bacteroides dorei. We then compare the pNPG and diclofenac glucuronide processing abilities of a panel of twelve structurally diverse GUS proteins, and find that the new L1 GUS enzymes presented here process small glucuronide substrates inefficiently compared to previously characterized L1 GUS enzymes like E. coli GUS. We further demonstrate that our GUS inhibitors, which are effective against some L1 enzymes, are not potent towards all. Our findings pinpoint active site structural features necessary for the processing of drug-glucuronide substrates and the inhibition of such processing.
Collapse
Affiliation(s)
- Kristen A Biernat
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Samuel J Pellock
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Aadra P Bhatt
- Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Marissa M Bivins
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - William G Walton
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Bich Ngoc T Tran
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Lianjie Wei
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Michael C Snider
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Andrew P Cesmat
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Ashutosh Tripathy
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Dorothy A Erie
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Matthew R Redinbo
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA. .,Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA. .,Department of Microbiology and Immunology, and Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA.
| |
Collapse
|
13
|
Andres SN, Li ZM, Erie DA, Williams RS. Ctp1 protein-DNA filaments promote DNA bridging and DNA double-strand break repair. J Biol Chem 2019; 294:3312-3320. [PMID: 30626735 DOI: 10.1074/jbc.ra118.006759] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 12/26/2018] [Indexed: 12/13/2022] Open
Abstract
The Ctp1 protein in Schizosaccharomyces pombe is essential for DNA double-strand break (DSB) repair by homologous recombination. Fission yeast Ctp1 and its budding yeast (Sae2) and human (CtIP) homologs control Mre11-Rad50-Nbs1 nuclease complex activity and harbor DNA-binding and -bridging activities. However, the molecular basis for Ctp1-DNA transactions remains undefined. Here, we report atomic force microscopy (AFM) imaging of S. pombe Ctp1-DNA complexes revealing that Ctp1 polymerizes on dsDNA molecules and forms synaptic filaments that bridge two dsDNA strands. We observed that Ctp1 DNA filaments are typified by an average filament length of ∼180 bp of dsDNA and a Ctp1 tetramer footprint of ∼15 bp. Biochemical results characterizing Ctp1 variants with impaired DNA-binding or -bridging properties were consistent with Ctp1-mediated DNA bridging requiring the intact and correctly folded Ctp1 tetramer. Furthermore, mutations altering Ctp1 oligomerization and DNA bridging in vitro conferred cell sensitivity to DSB-producing agents. Together, these results support an important role for Ctp1-regulated DNA strand coordination required for DNA DSB repair in S. pombe.
Collapse
Affiliation(s)
- Sara N Andres
- From the Genome Integrity and Structural Biology Laboratory, NIEHS, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina 27709
| | - Zimeng M Li
- the Department of Physics and Astronomy, University of North Carolina, Chapel Hill, North Carolina 27695, and
| | - Dorothy A Erie
- the Department of Chemistry, Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina 27599
| | - R Scott Williams
- From the Genome Integrity and Structural Biology Laboratory, NIEHS, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina 27709,
| |
Collapse
|
14
|
Hayne CK, Yumerefendi H, Cao L, Gauer JW, Lafferty MJ, Kuhlman B, Erie DA, Neher SB. We FRET so You Don't Have To: New Models of the Lipoprotein Lipase Dimer. Biochemistry 2018; 57:241-254. [PMID: 29303250 DOI: 10.1021/acs.biochem.7b01009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Lipoprotein lipase (LPL) is a dimeric enzyme that is responsible for clearing triglyceride-rich lipoproteins from the blood. Although LPL plays a key role in cardiovascular health, an experimentally derived three-dimensional structure has not been determined. Such a structure would aid in understanding mutations in LPL that cause familial LPL deficiency in patients and help in the development of therapeutic strategies to target LPL. A major obstacle to structural studies of LPL is that LPL is an unstable protein that is difficult to produce in the quantities needed for nuclear magnetic resonance or crystallography. We present updated LPL structural models generated by combining disulfide mapping, computational modeling, and data derived from single-molecule Förster resonance energy transfer (smFRET). We pioneer the technique of smFRET for use with LPL by developing conditions for imaging active LPL and identifying positions in LPL for the attachment of fluorophores. Using this approach, we measure LPL-LPL intermolecular interactions to generate experimental constraints that inform new computational models of the LPL dimer structure. These models suggest that LPL may dimerize using an interface that is different from the dimerization interface suggested by crystal packing contacts seen in structures of pancreatic lipase.
Collapse
Affiliation(s)
- Cassandra K Hayne
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599, United States
| | - Hayretin Yumerefendi
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599, United States
| | - Lin Cao
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599, United States
| | - Jacob W Gauer
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27514, United States
| | - Michael J Lafferty
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599, United States
| | - Brian Kuhlman
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599, United States.,Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599, United States
| | - Dorothy A Erie
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27514, United States.,Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599, United States
| | - Saskia B Neher
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599, United States
| |
Collapse
|
15
|
LeBlanc S, Wilkins H, Li Z, Kaur P, Wang H, Erie DA. Using Atomic Force Microscopy to Characterize the Conformational Properties of Proteins and Protein-DNA Complexes That Carry Out DNA Repair. Methods Enzymol 2017; 592:187-212. [PMID: 28668121 PMCID: PMC5761736 DOI: 10.1016/bs.mie.2017.04.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Atomic force microscopy (AFM) is a scanning probe technique that allows visualization of single biomolecules and complexes deposited on a surface with nanometer resolution. AFM is a powerful tool for characterizing protein-protein and protein-DNA interactions. It can be used to capture snapshots of protein-DNA solution dynamics, which in turn, enables the characterization of the conformational properties of transient protein-protein and protein-DNA interactions. With AFM, it is possible to determine the stoichiometries and binding affinities of protein-protein and protein-DNA associations, the specificity of proteins binding to specific sites on DNA, and the conformations of the complexes. We describe methods to prepare and deposit samples, including surface treatments for optimal depositions, and how to quantitatively analyze images. We also discuss a new electrostatic force imaging technique called DREEM, which allows the visualization of the path of DNA within proteins in protein-DNA complexes. Collectively, these methods facilitate the development of comprehensive models of DNA repair and provide a broader understanding of all protein-protein and protein-nucleic acid interactions. The structural details gleaned from analysis of AFM images coupled with biochemistry provide vital information toward establishing the structure-function relationships that govern DNA repair processes.
Collapse
Affiliation(s)
- Sharonda LeBlanc
- University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Hunter Wilkins
- University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Zimeng Li
- University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Parminder Kaur
- North Carolina State University, Raleigh, NC, United States
| | - Hong Wang
- North Carolina State University, Raleigh, NC, United States
| | - Dorothy A Erie
- University of North Carolina at Chapel Hill, Chapel Hill, NC, United States; Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States.
| |
Collapse
|
16
|
Bellendir SP, Rognstad DJ, Morris LP, Zapotoczny G, Walton WG, Redinbo MR, Ramsden DA, Sekelsky J, Erie DA. Substrate preference of Gen endonucleases highlights the importance of branched structures as DNA damage repair intermediates. Nucleic Acids Res 2017; 45:5333-5348. [PMID: 28369583 PMCID: PMC5435919 DOI: 10.1093/nar/gkx214] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Revised: 02/16/2017] [Accepted: 03/21/2017] [Indexed: 11/20/2022] Open
Abstract
Human GEN1 and yeast Yen1 are endonucleases with the ability to cleave Holliday junctions (HJs), which are proposed intermediates in recombination. In vivo, GEN1 and Yen1 function secondarily to Mus81, which has weak activity on intact HJs. We show that the genetic relationship is reversed in Drosophila, with Gen mutants having more severe defects than mus81 mutants. In vitro, DmGen, like HsGEN1, efficiently cleaves HJs, 5΄ flaps, splayed arms, and replication fork structures. We find that the cleavage rates for 5΄ flaps are significantly higher than those for HJs for both DmGen and HsGEN1, even in vast excess of enzyme over substrate. Kinetic studies suggest that the difference in cleavage rates results from a slow, rate-limiting conformational change prior to HJ cleavage: formation of a productive dimer on the HJ. Despite the stark difference in vivo that Drosophila uses Gen over Mus81 and humans use MUS81 over GEN1, we find the in vitro activities of DmGen and HsGEN1 to be strikingly similar. These findings suggest that simpler branched structures may be more important substrates for Gen orthologs in vivo, and highlight the utility of using the Drosophila model system to further understand these enzymes.
Collapse
Affiliation(s)
| | | | - Lydia P. Morris
- Lineberger Comprehensive Cancer Center, Chapel Hill, NC 27599, USA
| | | | | | - Matthew R. Redinbo
- Department of Chemistry, Chapel Hill, NC 27599, USA
- Integrative Program for Biological and Genome Sciences, Chapel Hill, NC 27599, USA
| | - Dale A. Ramsden
- Curriculum in Genetics and Molecular Biology, Chapel Hill, NC 27599, USA
- Lineberger Comprehensive Cancer Center, Chapel Hill, NC 27599, USA
- Department of Biochemistry and Biophysics, Chapel Hill, NC 27599, USA
| | - Jeff Sekelsky
- Curriculum in Genetics and Molecular Biology, Chapel Hill, NC 27599, USA
- Lineberger Comprehensive Cancer Center, Chapel Hill, NC 27599, USA
- Integrative Program for Biological and Genome Sciences, Chapel Hill, NC 27599, USA
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Dorothy A. Erie
- Department of Chemistry, Chapel Hill, NC 27599, USA
- Integrative Program for Biological and Genome Sciences, Chapel Hill, NC 27599, USA
| |
Collapse
|
17
|
Harrison JS, Cornett EM, Goldfarb D, DaRosa PA, Li ZM, Yan F, Dickson BM, Guo AH, Cantu DV, Kaustov L, Brown PJ, Arrowsmith CH, Erie DA, Major MB, Klevit RE, Krajewski K, Kuhlman B, Strahl BD, Rothbart SB. Hemi-methylated DNA regulates DNA methylation inheritance through allosteric activation of H3 ubiquitylation by UHRF1. eLife 2016; 5. [PMID: 27595565 PMCID: PMC5012860 DOI: 10.7554/elife.17101] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 08/05/2016] [Indexed: 12/21/2022] Open
Abstract
The epigenetic inheritance of DNA methylation requires UHRF1, a histone- and DNA-binding RING E3 ubiquitin ligase that recruits DNMT1 to sites of newly replicated DNA through ubiquitylation of histone H3. UHRF1 binds DNA with selectivity towards hemi-methylated CpGs (HeDNA); however, the contribution of HeDNA sensing to UHRF1 function remains elusive. Here, we reveal that the interaction of UHRF1 with HeDNA is required for DNA methylation but is dispensable for chromatin interaction, which is governed by reciprocal positive cooperativity between the UHRF1 histone- and DNA-binding domains. HeDNA recognition activates UHRF1 ubiquitylation towards multiple lysines on the H3 tail adjacent to the UHRF1 histone-binding site. Collectively, our studies are the first demonstrations of a DNA-protein interaction and an epigenetic modification directly regulating E3 ubiquitin ligase activity. They also define an orchestrated epigenetic control mechanism involving modifications both to histones and DNA that facilitate UHRF1 chromatin targeting, H3 ubiquitylation, and DNA methylation inheritance. DOI:http://dx.doi.org/10.7554/eLife.17101.001 Cells are able to regulate the activity of their genes in response to different cues. Genetic information is encoded in DNA and one way to regulate gene activity is to modify the DNA by attaching chemical “epigenetic” markers to it. When a cell divides, these epigenetic markers can be inherited by the daughter cells so that they share the same patterns of gene activity as the parent cell. When the DNA of the parent cell is copied prior to cell division, the epigenetic markers are also copied onto the new DNA. Mistakes in this process are linked to a wide range of diseases in humans, such as cancer and neurological disorders. One type of epigenetic marker is known as a methyl tag and it is added to DNA by certain enzymes in a process called DNA methylation. A protein called UHRF1 is required for human cells to inherit patterns of DNA methylation through cell division. This protein binds to newly copied DNA that lacks some methyl tags as well as to another protein associated with DNA called histone H3. UHRF1 modifies histone H3 by attaching a small protein molecule called ubiquitin to it. This helps to recruit a DNA methylation enzyme to place methyl tags on the newly copied DNA. However, it was not clear how the various properties of UHRF1 allow it to control how DNA methylation is inherited. Harrison et al. addressed this question by studying purified proteins and DNA fragments outside of living cells. The results show that UHRF1 binding to DNA and histone H3 work together to bring UHRF1 to the sites on DNA that require methylation. Further experiments revealed that the methylation pattern on newly copied DNA is able to activate the ability of UHRF1 to place ubiquitin on histone H3. The findings of Harrison et al. reveal a new mechanism by which dividing cells control how DNA methylation is inherited by their daughter cells. A future challenge will be to find out how attaching ubiquitin to histone H3 activates DNA methylation. DOI:http://dx.doi.org/10.7554/eLife.17101.002
Collapse
Affiliation(s)
- Joseph S Harrison
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, United States.,Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - Evan M Cornett
- Center for Epigenetics, Van Andel Research Institute, Grand Rapids, United States
| | - Dennis Goldfarb
- Department of Computer Science, University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - Paul A DaRosa
- Department of Biochemistry, University of Washington, Seattle, United States
| | - Zimeng M Li
- Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - Feng Yan
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - Bradley M Dickson
- Center for Epigenetics, Van Andel Research Institute, Grand Rapids, United States
| | - Angela H Guo
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - Daniel V Cantu
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - Lilia Kaustov
- Structural Genomics Consortium, University of Toronto, Toronto, Canada
| | - Peter J Brown
- Structural Genomics Consortium, University of Toronto, Toronto, Canada
| | | | - Dorothy A Erie
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - Michael B Major
- Department of Computer Science, University of North Carolina at Chapel Hill, Chapel Hill, United States.,Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - Rachel E Klevit
- Department of Biochemistry, University of Washington, Seattle, United States
| | - Krzysztof Krajewski
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - Brian Kuhlman
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, United States.,Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - Brian D Strahl
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, United States.,Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - Scott B Rothbart
- Center for Epigenetics, Van Andel Research Institute, Grand Rapids, United States
| |
Collapse
|
18
|
Kaur P, Wu D, Lin J, Countryman P, Bradford KC, Erie DA, Riehn R, Opresko PL, Wang H. Enhanced electrostatic force microscopy reveals higher-order DNA looping mediated by the telomeric protein TRF2. Sci Rep 2016; 6:20513. [PMID: 26856421 PMCID: PMC4746636 DOI: 10.1038/srep20513] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Accepted: 01/04/2016] [Indexed: 12/19/2022] Open
Abstract
Shelterin protein TRF2 modulates telomere structures by promoting dsDNA compaction and T-loop formation. Advancement of our understanding of the mechanism underlying TRF2-mediated DNA compaction requires additional information regarding DNA paths in TRF2-DNA complexes. To uncover the location of DNA inside protein-DNA complexes, we recently developed the Dual-Resonance-frequency-Enhanced Electrostatic force Microscopy (DREEM) imaging technique. DREEM imaging shows that in contrast to chromatin with DNA wrapping around histones, large TRF2-DNA complexes (with volumes larger than TRF2 tetramers) compact DNA inside TRF2 with portions of folded DNA appearing at the edge of these complexes. Supporting coarse-grained molecular dynamics simulations uncover the structural requirement and sequential steps during TRF2-mediated DNA compaction and result in folded DNA structures with protruding DNA loops as seen in DREEM imaging. Revealing DNA paths in TRF2 complexes provides new mechanistic insights into structure-function relationships underlying telomere maintenance pathways.
Collapse
Affiliation(s)
- Parminder Kaur
- Physics Department, North Carolina State University, Raleigh, North Carolina, NC 27695, USA
| | - Dong Wu
- Physics Department, North Carolina State University, Raleigh, North Carolina, NC 27695, USA
| | - Jiangguo Lin
- Physics Department, North Carolina State University, Raleigh, North Carolina, NC 27695, USA.,School of Bioscience and Engineering, South China University of Technology, Guangzhou, Guangdong 510006, P.R. China
| | - Preston Countryman
- Physics Department, North Carolina State University, Raleigh, North Carolina, NC 27695, USA
| | - Kira C Bradford
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599
| | - Dorothy A Erie
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599.,Curriculum in Applied Sciences and Engineering, University of North Carolina, Chapel Hill, NC 27599
| | - Robert Riehn
- Physics Department, North Carolina State University, Raleigh, North Carolina, NC 27695, USA
| | - Patricia L Opresko
- Department of Environmental and Occupational Health, University of Pittsburgh Graduate School of Public Health, Pittsburgh, Pennsylvania 15219, USA
| | - Hong Wang
- Physics Department, North Carolina State University, Raleigh, North Carolina, NC 27695, USA
| |
Collapse
|
19
|
Wu D, Kaur P, Li ZM, Bradford KC, Wang H, Erie DA. Visualizing the Path of DNA through Proteins Using DREEM Imaging. Mol Cell 2016; 61:315-23. [PMID: 26774284 DOI: 10.1016/j.molcel.2015.12.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 10/14/2015] [Accepted: 12/02/2015] [Indexed: 01/06/2023]
Abstract
Many cellular functions require the assembly of multiprotein-DNA complexes. A growing area of structural biology aims to characterize these dynamic structures by combining atomic-resolution crystal structures with lower-resolution data from techniques that provide distributions of species, such as small-angle X-ray scattering, electron microscopy, and atomic force microscopy (AFM). A significant limitation in these combinatorial methods is localization of the DNA within the multiprotein complex. Here, we combine AFM with an electrostatic force microscopy (EFM) method to develop an exquisitely sensitive dual-resonance-frequency-enhanced EFM (DREEM) capable of resolving DNA within protein-DNA complexes. Imaging of nucleosomes and DNA mismatch repair complexes demonstrates that DREEM can reveal both the path of the DNA wrapping around histones and the path of DNA as it passes through both single proteins and multiprotein complexes. Finally, DREEM imaging requires only minor modifications of many existing commercial AFMs, making the technique readily available.
Collapse
Affiliation(s)
- Dong Wu
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Parminder Kaur
- Department of Physics, North Carolina State University, Raleigh, NC 27695, USA
| | - Zimeng M Li
- Department of Physics and Astronomy, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Kira C Bradford
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Hong Wang
- Department of Physics, North Carolina State University, Raleigh, NC 27695, USA; Center for Human Health and the Environment, North Carolina State University, Raleigh, NC 27695, USA.
| | - Dorothy A Erie
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599, USA; Curriculum in Applied Sciences and Engineering, University of North Carolina, Chapel Hill, NC 27599, USA.
| |
Collapse
|
20
|
Vermulst M, Denney AS, Lang MJ, Hung CW, Moore S, Moseley MA, Thompson JW, Madden V, Gauer J, Wolfe KJ, Summers DW, Schleit J, Sutphin GL, Haroon S, Holczbauer A, Caine J, Jorgenson J, Cyr D, Kaeberlein M, Strathern JN, Duncan MC, Erie DA. Corrigendum: Transcription errors induce proteotoxic stress and shorten cellular lifespan. Nat Commun 2015; 6:8738. [PMID: 26465398 DOI: 10.1038/ncomms9738] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
|
21
|
Vermulst M, Denney AS, Lang MJ, Hung CW, Moore S, Moseley MA, Mosely AM, Thompson JW, Thompson WJ, Madden V, Gauer J, Wolfe KJ, Summers DW, Schleit J, Sutphin GL, Haroon S, Holczbauer A, Caine J, Jorgenson J, Cyr D, Kaeberlein M, Strathern JN, Duncan MC, Erie DA. Transcription errors induce proteotoxic stress and shorten cellular lifespan. Nat Commun 2015; 6:8065. [PMID: 26304740 DOI: 10.1038/ncomms9065] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 07/14/2015] [Indexed: 11/09/2022] Open
Abstract
Transcription errors occur in all living cells; however, it is unknown how these errors affect cellular health. To answer this question, we monitor yeast cells that are genetically engineered to display error-prone transcription. We discover that these cells suffer from a profound loss in proteostasis, which sensitizes them to the expression of genes that are associated with protein-folding diseases in humans; thus, transcription errors represent a new molecular mechanism by which cells can acquire disease phenotypes. We further find that the error rate of transcription increases as cells age, suggesting that transcription errors affect proteostasis particularly in aging cells. Accordingly, transcription errors accelerate the aggregation of a peptide that is implicated in Alzheimer's disease, and shorten the lifespan of cells. These experiments reveal a previously unappreciated role for transcriptional fidelity in cellular health and aging.
Collapse
Affiliation(s)
- Marc Vermulst
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599, USA.,Center for Mitochondrial and Epigenomic Medicine, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA
| | - Ashley S Denney
- School of Medicine, University of Colorado, Denver, Colorado 80217, USA
| | - Michael J Lang
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Chao-Wei Hung
- Department of Biology, University of North Carolina, Chapel Hill, North Carolina 27599, USA
| | - Stephanie Moore
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599, USA
| | - M Arthur Moseley
- Proteomics Core Facility, Duke University, Durham, North Carolina 27710, USA
| | - Arthur M Mosely
- Proteomics Core Facility, Duke University, Durham, North Carolina 27710, USA
| | - J Will Thompson
- Proteomics Core Facility, Duke University, Durham, North Carolina 27710, USA
| | - William J Thompson
- Proteomics Core Facility, Duke University, Durham, North Carolina 27710, USA
| | - Victoria Madden
- Microscopy Services Laboratory, School of Medicine, University of North Carolina, Chapel Hill, North Carolina 27599, USA
| | - Jacob Gauer
- Department of Biology, University of North Carolina, Chapel Hill, North Carolina 27599, USA
| | - Katie J Wolfe
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, North Carolina 27599, USA
| | - Daniel W Summers
- Department of Developmental Biology, and Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, Missouri 63110, USA
| | - Jennifer Schleit
- Department of Pathology, University of Washington, Seattle, Washington 98195, USA
| | - George L Sutphin
- Department of Pathology, University of Washington, Seattle, Washington 98195, USA
| | - Suraiya Haroon
- Center for Mitochondrial and Epigenomic Medicine, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA
| | - Agnes Holczbauer
- Center for Mitochondrial and Epigenomic Medicine, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA
| | - Joanne Caine
- CSIRO, Department of Materials Science and Engineering, Parkville 3052, Australia
| | - James Jorgenson
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599, USA
| | - Douglas Cyr
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, North Carolina 27599, USA
| | - Matt Kaeberlein
- Department of Pathology, University of Washington, Seattle, Washington 98195, USA
| | - Jeffrey N Strathern
- Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702, USA
| | - Mara C Duncan
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Dorothy A Erie
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599, USA.,Department of Chemistry, Curriculum in Applied Sciences and Engineering, University of North Carolina, Chapel Hill, North Carolina 27599, USA
| |
Collapse
|
22
|
Abstract
Three processes act in series to accurately replicate the eukaryotic nuclear genome. The major replicative DNA polymerases strongly prevent mismatch formation, occasional mismatches that do form are proofread during replication, and rare mismatches that escape proofreading are corrected by mismatch repair (MMR). This review focuses on MMR in light of increasing knowledge about nuclear DNA replication enzymology and the rate and specificity with which mismatches are generated during leading- and lagging-strand replication. We consider differences in MMR efficiency in relation to mismatch recognition, signaling to direct MMR to the nascent strand, mismatch removal, and the timing of MMR. These studies are refining our understanding of relationships between generating and repairing replication errors to achieve accurate replication of both DNA strands of the nuclear genome.
Collapse
Affiliation(s)
- Thomas A Kunkel
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, North Carolina 27709;
| | - Dorothy A Erie
- Department of Chemistry and Curriculum in Applied Sciences and Engineering, University of North Carolina, Chapel Hill, North Carolina 27599-3290;
| |
Collapse
|
23
|
Abstract
DNA mismatch repair, which involves is a widely conserved set of proteins, is essential to limit genetic drift in all organisms. The same system of proteins plays key roles in many cancer related cellular transactions in humans. Although the basic process has been reconstituted in vitro using purified components, many fundamental aspects of DNA mismatch repair remain hidden due in part to the complexity and transient nature of the interactions between the mismatch repair proteins and DNA substrates. Single molecule methods offer the capability to uncover these transient but complex interactions and allow novel insights into mechanisms that underlie DNA mismatch repair. In this review, we discuss applications of single molecule methodology including electron microscopy, atomic force microscopy, particle tracking, FRET, and optical trapping to studies of DNA mismatch repair. These studies have led to formulation of mechanistic models of how proteins identify single base mismatches in the vast background of matched DNA and signal for their repair.
Collapse
Affiliation(s)
- Dorothy A Erie
- Department of Chemistry and Curriculum in Applied Sciences and Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States.
| | - Keith R Weninger
- Department of Physics, North Carolina State University, Raleigh, NC 27695, United States
| |
Collapse
|
24
|
Abstract
![]()
MutS
recognizes base–base mismatches and base insertions/deletions
(IDLs) in newly replicated DNA. Specific interactions between MutS
and these errors trigger a cascade of protein–protein interactions
that ultimately lead to their repair. The inability to explain why
different DNA errors are repaired with widely varying efficiencies in vivo remains an outstanding example of our limited knowledge
of this process. Here, we present single-molecule Förster resonance
energy transfer measurements of the DNA bending dynamics induced by Thermus aquaticus MutS and the E41A mutant of MutS, which
is known to have error specific deficiencies in signaling repair.
We compared three DNA mismatches/IDLs (T-bulge, GT, and CC) with repair
efficiencies ranging from high to low. We identify three dominant
DNA bending states [slightly bent/unbent (U), intermediately
bent (I), and significantly bent (B)] and
find that the kinetics of interconverting among states varies widely
for different complexes. The increased stability of MutS–mismatch/IDL
complexes is associated with stabilization of U and lowering
of the B to U transition barrier. Destabilization
of U is always accompanied by a destabilization of B, supporting the suggestion that B is a “required”
precursor to U. Comparison of MutS and MutS-E41A dynamics
on GT and the T-bulge suggests that hydrogen bonding to MutS facilitates
the changes in base–base hydrogen bonding that are required
to achieve the U state, which has been implicated in
repair signaling. Taken together with repair propensities, our data
suggest that the bending kinetics of MutS–mismatched DNA complexes
may control the entry into functional pathways for downstream signaling
of repair.
Collapse
Affiliation(s)
- Vanessa C DeRocco
- Department of Chemistry and ‡Curriculum in Applied Sciences and Engineering, The University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599, United States
| | | | | | | | | |
Collapse
|
25
|
Abstract
Elevated triglycerides are associated with an increased risk of cardiovascular disease, and lipoprotein lipase (LPL) is the rate-limiting enzyme for the hydrolysis of triglycerides from circulating lipoproteins. The N-terminal domain of angiopoietin-like protein 4 (ANGPTL4) inhibits LPL activity. ANGPTL4 was previously described as an unfolding molecular chaperone of LPL that catalytically converts active LPL dimers into inactive monomers. Our studies show that ANGPTL4 is more accurately described as a reversible, noncompetitive inhibitor of LPL. We find that inhibited LPL is in a complex with ANGPTL4, and upon dissociation, LPL regains lipase activity. Furthermore, we have generated a variant of ANGPTL4 that is dependent on divalent cations for its ability to inhibit LPL. We show that LPL inactivation by this regulatable variant of ANGPTL4 is fully reversible after treatment with a chelator.
Collapse
Affiliation(s)
| | - Kira C. Bradford
- Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Dorothy A. Erie
- Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Saskia B. Neher
- From the Departments of Biochemistry and Biophysics, and
- To whom correspondence may be addressed: Dept. of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, 120 Mason Farm Rd., CB 7260, Chapel Hill, NC 27599. Tel.: 919-966-9550; E-mail:
| |
Collapse
|
26
|
Abstract
We have developed a model for the secondary structure of the 1058-nucleotide plus-strand RNA genome of the icosahedral satellite tobacco mosaic virus (STMV) using nucleotide-resolution SHAPE chemical probing of the viral RNA isolated from virions and within the virion, perturbation of interactions distant in the primary sequence, and atomic force microscopy. These data are consistent with long-range base pairing interactions and a three-domain genome architecture. The compact domains of the STMV RNA have dimensions of 10-45 nm. Each of the three domains corresponds to a specific functional component of the virus: The central domain corresponds to the coding sequence of the single (capsid) protein encoded by the virus, whereas the 5' and 3' untranslated domains span signals essential for translation and replication, respectively. This three-domain architecture is compatible with interactions between the capsid protein and short RNA helices previously visualized by crystallography. STMV is among the simplest of the icosahedral viruses but, nonetheless, has an RNA genome with a complex higher-order structure that likely reflects high information content and an evolutionary relationship between RNA domain structure and essential replicative functions.
Collapse
Affiliation(s)
- Eva J Archer
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599-3290, USA
| | | | | | | | | | | | | | | |
Collapse
|
27
|
Geng H, Sakato M, DeRocco V, Yamane K, Du C, Erie DA, Hingorani M, Hsieh P. Biochemical analysis of the human mismatch repair proteins hMutSalpha MSH2G674A‐MSH6 and MSH2‐MSH6T1219D. FASEB J 2012. [DOI: 10.1096/fasebj.26.1_supplement.lb83] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Hui Geng
- NIDDKNational Institutie of HealthBethesdaMD
| | | | | | | | - Chunwei Du
- NIDDKNational Institutie of HealthBethesdaMD
| | | | | | - Peggy Hsieh
- NIDDKNational Institutie of HealthBethesdaMD
| |
Collapse
|
28
|
Geng H, Sakato M, DeRocco V, Yamane K, Du C, Erie DA, Hingorani M, Hsieh P. Biochemical analysis of the human mismatch repair proteins hMutSα MSH2(G674A)-MSH6 and MSH2-MSH6(T1219D). J Biol Chem 2012; 287:9777-9791. [PMID: 22277660 DOI: 10.1074/jbc.m111.316919] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The heterodimeric human MSH2-MSH6 protein initiates DNA mismatch repair (MMR) by recognizing mismatched bases that result from replication errors. Msh2(G674A) or Msh6(T1217D) mice that have mutations in or near the ATP binding site of MSH2 or ATP hydrolysis catalytic site of MSH6 develop cancer and have a reduced lifespan due to loss of the MMR pathway (Lin, D. P., Wang, Y., Scherer, S. J., Clark, A. B., Yang, K., Avdievich, E., Jin, B., Werling, U., Parris, T., Kurihara, N., Umar, A., Kucherlapati, R., Lipkin, M., Kunkel, T. A., and Edelmann, W. (2004) Cancer Res. 64, 517-522; Yang, G., Scherer, S. J., Shell, S. S., Yang, K., Kim, M., Lipkin, M., Kucherlapati, R., Kolodner, R. D., and Edelmann, W. (2004) Cancer Cell 6, 139-150). Mouse embryonic fibroblasts from these mice retain an apoptotic response to DNA damage. Mutant human MutSα proteins MSH2(G674A)-MSH6(wt) and MSH2(wt)-MSH6(T1219D) are profiled in a variety of functional assays and as expected fail to support MMR in vitro, although they retain mismatch recognition activity. Kinetic analyses of DNA binding and ATPase activities and examination of the excision step of MMR reveal that the two mutants differ in their underlying molecular defects. MSH2(wt)-MSH6(T1219D) fails to couple nucleotide binding and mismatch recognition, whereas MSH2(G674A)-MSH6(wt) has a partial defect in nucleotide binding. Nevertheless, both mutant proteins remain bound to the mismatch and fail to promote efficient excision thereby inhibiting MMR in vitro in a dominant manner. Implications of these findings for MMR and DNA damage signaling by MMR proteins are discussed.
Collapse
Affiliation(s)
- Hui Geng
- Genetics and Biochemistry Branch, NIDDK, National Institutes of Health, Bethesda, Maryland 20892
| | - Miho Sakato
- Molecular Biology and Biochemistry Department, Wesleyan University, Middletown, Connecticut 06459, and
| | - Vanessa DeRocco
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Kazuhiko Yamane
- Genetics and Biochemistry Branch, NIDDK, National Institutes of Health, Bethesda, Maryland 20892
| | - Chunwei Du
- Genetics and Biochemistry Branch, NIDDK, National Institutes of Health, Bethesda, Maryland 20892
| | - Dorothy A Erie
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Manju Hingorani
- Molecular Biology and Biochemistry Department, Wesleyan University, Middletown, Connecticut 06459, and
| | - Peggy Hsieh
- Genetics and Biochemistry Branch, NIDDK, National Institutes of Health, Bethesda, Maryland 20892,.
| |
Collapse
|
29
|
DeRocco V, Anderson T, Piehler J, Erie DA, Weninger K. Four-color single-molecule fluorescence with noncovalent dye labeling to monitor dynamic multimolecular complexes. Biotechniques 2011; 49:807-16. [PMID: 21091445 DOI: 10.2144/000113551] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
To enable studies of conformational changes within multimolecular complexes, we present a simultaneous, four-color single molecule fluorescence methodology implemented with total internal reflection illumination and camera-based, wide-field detection. We further demonstrate labeling histidine-tagged proteins noncovalently with Tris-nitrilotriacetic acid (Tris-NTA)-conjugated dyes to achieve single molecule detection. We combine these methods to colocalize the mismatch repair protein MutSα on DNA while monitoring MutSα-induced DNA bending using Förster resonance energy transfer (FRET) and to monitor assembly of membrane-tethered SNARE protein complexes.
Collapse
Affiliation(s)
- Vanessa DeRocco
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
| | | | | | | | | |
Collapse
|
30
|
Fronczek DN, Quammen C, Wang H, Kisker C, Superfine R, Taylor R, Erie DA, Tessmer I. High accuracy FIONA-AFM hybrid imaging. Ultramicroscopy 2011; 111:350-5. [PMID: 21329649 DOI: 10.1016/j.ultramic.2011.01.020] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2010] [Revised: 11/03/2010] [Accepted: 01/11/2011] [Indexed: 11/24/2022]
Abstract
Multi-protein complexes are ubiquitous and play essential roles in many biological mechanisms. Single molecule imaging techniques such as electron microscopy (EM) and atomic force microscopy (AFM) are powerful methods for characterizing the structural properties of multi-protein and multi-protein-DNA complexes. However, a significant limitation to these techniques is the ability to distinguish different proteins from one another. Here, we combine high resolution fluorescence microscopy and AFM (FIONA-AFM) to allow the identification of different proteins in such complexes. Using quantum dots as fiducial markers in addition to fluorescently labeled proteins, we are able to align fluorescence and AFM information to ≥8nm accuracy. This accuracy is sufficient to identify individual fluorescently labeled proteins in most multi-protein complexes. We investigate the limitations of localization precision and accuracy in fluorescence and AFM images separately and their effects on the overall registration accuracy of FIONA-AFM hybrid images. This combination of the two orthogonal techniques (FIONA and AFM) opens a wide spectrum of possible applications to the study of protein interactions, because AFM can yield high resolution (5-10nm) information about the conformational properties of multi-protein complexes and the fluorescence can indicate spatial relationships of the proteins in the complexes.
Collapse
Affiliation(s)
- D N Fronczek
- Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg, Josef Schneider Strasse 2, 97080 Würzburg, Germany
| | | | | | | | | | | | | | | |
Collapse
|
31
|
Tsai HH, Huang CH, Tessmer I, Erie DA, Chen CW. Linear Streptomyces plasmids form superhelical circles through interactions between their terminal proteins. Nucleic Acids Res 2010; 39:2165-74. [PMID: 21109537 PMCID: PMC3064793 DOI: 10.1093/nar/gkq1204] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Linear chromosomes and linear plasmids of Streptomyces possess covalently bound terminal proteins (TPs) at the 5′ ends of their telomeres. These TPs are proposed to act as primers for DNA synthesis that patches the single-stranded gaps at the 3′ ends during replication. Most (‘archetypal’) Streptomyces TPs (designated Tpg) are highly conserved in size and sequence. In addition, there are a number of atypical TPs with heterologous sequences and sizes, one of which is Tpc that caps SCP1 plasmid of Streptomyces coelicolor. Interactions between the TPs on the linear Streptomyces replicons have been suggested by electrophoretic behaviors of TP-capped DNA and circular genetic maps of Streptomyces chromosomes. Using chemical cross-linking, we demonstrated intramolecular and intermolecular interactions in vivo between Tpgs, between Tpcs and between Tpg and Tpc. Interactions between the chromosomal and plasmid telomeres were also detected in vivo. The intramolecular telomere interactions produced negative superhelicity in the linear DNA, which was relaxed by topoisomerase I. Such intramolecular association between the TPs poses a post-replicational complication in the formation of a pseudo-dimeric structure that requires resolution by exchanging TPs or DNA.
Collapse
Affiliation(s)
- Hsiu-Hui Tsai
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Shih-Pai, Taipei 112, Taiwan
| | | | | | | | | |
Collapse
|
32
|
Abstract
The first step in DNA mismatch repair (MMR) is the recognition of DNA mismatches or nucleotide insertions/deletions (IDLs) by MutS and MutS homologues. To investigate the conformational properties of MutS-mismatch complexes, we used single-molecule fluorescence resonance energy transfer (smFRET) to examine the dynamics of MutS-induced DNA bending at a GT mismatch. The FRET measurements reveal that the MutS-GT mismatch recognition complex is highly dynamic, undergoing conformational transitions between many states with different degrees of DNA bending. Due to the complexity of the data, we developed an analysis approach, called FRET TACKLE, in which we combine direct analysis of FRET transitions with examination of kinetic lifetimes to identify all of the conformational states and characterize the kinetics of the binding and conformational equilibria. The data reveal that MutS-GT complexes can reside in six different conformations, which have lifetimes that differ by as much as 20-fold and exhibit rates of interconversion that vary by 2 orders of magnitude. To gain further insight into the dynamic properties of GT-MutS complexes and to bolster the validity of our analysis, we complemented our experimental data with Monte Carlo simulations. Taken together, our results suggest that the dynamics of the MutS-mismatch complex could govern the efficiency of repair of different DNA mismatches. Finally, in addition to revealing these important biological implications of MutS-DNA interactions, this FRET TACKLE method will enable the analysis of the complex dynamics of other biological systems.
Collapse
Affiliation(s)
- Lauryn E Sass
- Department of Chemistry, University of North Carolina, Chapel Hill,North Carolina 27599, USA
| | | | | | | |
Collapse
|
33
|
Chelico L, Prochnow C, Erie DA, Chen XS, Goodman MF. Structural model for deoxycytidine deamination mechanisms of the HIV-1 inactivation enzyme APOBEC3G. J Biol Chem 2010; 285:16195-205. [PMID: 20212048 DOI: 10.1074/jbc.m110.107987] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
APOBEC3G (Apo3G) is a single-stranded DNA-dependent deoxycytidine deaminase, which, in the absence of the human immunodeficiency virus (HIV) viral infectivity factor, is encapsulated into HIV virions. Subsequently, Apo3G triggers viral inactivation by processively deaminating C-->U, with 3'-->5' polarity, on nascent minus-strand cDNA. Apo3G has a catalytically inactive N-terminal CD1 domain and an active C-terminal CD2 domain. Apo3G exists as monomers, dimers, tetramers, and higher order oligomers whose distributions depend on DNA substrate and salt. Here we use multiangle light scattering and atomic force microscopy to identify oligomerization states of Apo3G. A double mutant (F126A/W127A), designed to disrupt dimerization at the predicted CD1-CD1 dimer interface, predominantly converts Apo3G to a monomer that binds single-stranded DNA, Alu RNA, and catalyzes processive C-->U deaminations with 3'-->5' deamination polarity, similar to native Apo3G. The CD1 domain is essential for both processivity and polarity. We propose a structure-based model to explain the scanning and catalytic behavior of Apo3G.
Collapse
Affiliation(s)
- Linda Chelico
- Department of Biological Sciences, University of Southern California, Los Angeles, California 90089-2910, USA
| | | | | | | | | |
Collapse
|
34
|
Erie DA, Kennedy SR. Forks, pincers, and triggers: the tools for nucleotide incorporation and translocation in multi-subunit RNA polymerases. Curr Opin Struct Biol 2009; 19:708-14. [PMID: 19913407 PMCID: PMC3979713 DOI: 10.1016/j.sbi.2009.10.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2009] [Revised: 10/12/2009] [Accepted: 10/14/2009] [Indexed: 01/22/2023]
Abstract
The central role of RNA polymerase (RNAP) is to catalyze the processive synthesis of a growing RNA transcript. Recent structural and biophysical data have led to a deeper understanding of the nucleotide addition cycle and insight into the structure-function relationships that govern transcription elongation. In this review, we discuss kinetic data on nucleotide incorporation in the context of crystal structures, which show RNAP in multiple conformations. We present a facilitated Brownian ratchet model of nucleotide incorporation, in which templated NTP binding to a non-catalytic site in the main channel promotes the conformational changes that lead to opening of the catalytic site and translocation.
Collapse
Affiliation(s)
- Dorothy A Erie
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599, United States.
| | | |
Collapse
|
35
|
Abstract
At many promoters, transcription is regulated by simultaneous binding of a protein to multiple sites on DNA, but the structures and dynamics of such transcription factor-mediated DNA loops are poorly understood. We directly examined in vitro loop formation mediated by Escherichia coli lactose repressor using single-molecule structural and kinetics methods. Small (∼150 bp) loops form quickly and stably, even with out-of-phase operator spacings. Unexpectedly, repeated spontaneous transitions between two distinct loop structures were observed in individual protein–DNA complexes. The results imply a dynamic equilibrium between a novel loop structure with the repressor in its crystallographic “V” conformation and a second structure with a more extended linear repressor conformation that substantially lessens the DNA bending strain. The ability to switch between different loop structures may help to explain how robust transcription regulation is maintained even though the mechanical work required to form a loop may change substantially with metabolic conditions. Some proteins that regulate DNA transcription do so by binding simultaneously to two separated sites on the DNA molecule, forming a DNA loop. Although such loops are common, many of their features are poorly characterized. Of particular interest is the question of how some proteins accommodate the formation of loops of different sizes, particularly when the loops are small and thus require strong bending (and, in some cases, twisting) of the DNA to form. We observed the shape and behavior of individual DNA molecules bent into tight loops by Lac repressor, a transcription-regulating protein from the bacterium Escherichia coli. Loops were formed in DNA molecules with repressor-binding sites on opposite faces of the DNA double helix almost as readily as in those with sites on the same side, suggesting that the repressor is highly flexible. The DNA can switch back and forth between a tighter and a looser loop structure “on the fly” during the lifetime of a single loop, further evidence that Lac repressor is capable of adopting different shapes that may serve to minimize DNA bending or twisting in loops. The ability of the repressor to readily switch between different loop shapes may allow it to maintain effective control of transcription across situations in which the difficulty of bending or twisting DNA changes substantially. A large-scale conformational change in a transcription factor protein allows DNA loops to dynamically switch between alternative conformations that may contribute to robust transcription regulation.
Collapse
Affiliation(s)
- Oi Kwan Wong
- Department of Biochemistry, Brandeis University, Waltham, Massachusetts, United States of America
| | - Martin Guthold
- Department of Physics, Wake Forest University, Winston-Salem, North Carolina, United States of America
| | - Dorothy A Erie
- Department of Chemistry and Curriculum Applied and Materials Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Jeff Gelles
- Department of Biochemistry, Brandeis University, Waltham, Massachusetts, United States of America
- * To whom correspondence should be addressed. E-mail:
| |
Collapse
|
36
|
Tessmer I, Yang Y, Zhai J, Du C, Hsieh P, Hingorani MM, Erie DA. Mechanism of MutS searching for DNA mismatches and signaling repair. J Biol Chem 2008; 283:36646-54. [PMID: 18854319 DOI: 10.1074/jbc.m805712200] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
DNA mismatch repair is initiated by the recognition of mismatches by MutS proteins. The mechanism by which MutS searches for and recognizes mismatches and subsequently signals repair remains poorly understood. We used single-molecule analyses of atomic force microscopy images of MutS-DNA complexes, coupled with biochemical assays, to determine the distributions of conformational states, the DNA binding affinities, and the ATPase activities of wild type and two mutants of MutS, with alanine substitutions in the conserved Phe-Xaa-Glu mismatch recognition motif. We find that on homoduplex DNA, the conserved Glu, but not the Phe, facilitates MutS-induced DNA bending, whereas at mismatches, both Phe and Glu promote the formation of an unbent conformation. The data reveal an unusual role for the Phe residue in that it promotes the unbending, not bending, of DNA at mismatch sites. In addition, formation of the specific unbent MutS-DNA conformation at mismatches appears to be required for the inhibition of ATP hydrolysis by MutS that signals initiation of repair. These results provide a structural explanation for the mechanism by which MutS searches for and recognizes mismatches and for the observed phenotypes of mutants with substitutions in the Phe-Xaa-Glu motif.
Collapse
Affiliation(s)
- Ingrid Tessmer
- Department of Chemistry and Curriculum in Applied Sciences and Engineering, University of North Carolina, Chapel Hill, North Carolina 27599, USA
| | | | | | | | | | | | | |
Collapse
|
37
|
Campbell JF, Tessmer I, Thorp HH, Erie DA. Atomic Force Microscopy Studies of DNA-Wrapped Carbon Nanotube Structure and Binding to Quantum Dots. J Am Chem Soc 2008; 130:10648-55. [DOI: 10.1021/ja801720c] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jennifer F. Campbell
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | - Ingrid Tessmer
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | - H. Holden Thorp
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | - Dorothy A. Erie
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| |
Collapse
|
38
|
Wang H, Tessmer I, Croteau DL, Erie DA, Van Houten B. Functional characterization and atomic force microscopy of a DNA repair protein conjugated to a quantum dot. Nano Lett 2008; 8:1631-1637. [PMID: 18444686 PMCID: PMC3941028 DOI: 10.1021/nl080316l] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Quantum dots (QDs) possess highly desirable optical properties that make them ideal fluorescent labels for studying the dynamic behavior of proteins. However, a lack of characterization methods for reliably determining protein-quantum dot conjugate stoichiometry and functionality has impeded their widespread use in single-molecule studies. We used atomic force microscopic (AFM) imaging to demonstrate the 1:1 formation of UvrB-QD conjugates based on an antibody-sandwich method. We show that an agarose gel-based electrophoresis mobility shift assay and AFM can be used to evaluate the DNA binding function of UvrB-QD conjugates. Importantly, we demonstrate that quantum dots can serve as a molecular marker to unambiguously identify the presence of a labeled protein in AFM images.
Collapse
Affiliation(s)
| | | | | | - Dorothy A. Erie
- Corresponding authors: (D.A.E.); (B.V.H.). Telephone: (919) 962-6370 (D.A.E.); (919) 541-2799 (B.V.H.). Fax: (919) 962-2388 (D.A.E.); (919) 541-7593 (B.V.H.)
| | - Bennett Van Houten
- Corresponding authors: (D.A.E.); (B.V.H.). Telephone: (919) 962-6370 (D.A.E.); (919) 541-2799 (B.V.H.). Fax: (919) 962-2388 (D.A.E.); (919) 541-7593 (B.V.H.)
| |
Collapse
|
39
|
Chelico L, Sacho EJ, Erie DA, Goodman MF. A model for oligomeric regulation of APOBEC3G cytosine deaminase-dependent restriction of HIV. J Biol Chem 2008; 283:13780-91. [PMID: 18362149 DOI: 10.1074/jbc.m801004200] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
APOBEC3G (A3G) restricts HIV-1 infection by catalyzing processive C --> U deaminations on single-stranded DNA (ssDNA) with marked 3' --> 5' deamination polarity. Here we show that A3G exists in oligomeric states whose composition is dictated primarily by interactions with DNA, with salt playing an important, yet secondary, role. Directional deaminations correlate with the presence of dimers, tetramers, and larger oligomers observed by atomic force microscopy, and random deaminations appear to correlate mainly with monomers. The presence of a 30-nt weakly deaminated "dead" zone located at the 3'-ssDNA end implies the presence of a preferred asymmetric direction for A3G catalysis. Single turnover reaction rates reveal a salt-dependent inhibition of C deamination toward the 3'-ssDNA region, offering a molecular basis underlying A3G deamination polarity. Presteady state analysis demonstrates rapid diffusion-limited A3G-ssDNA binding, a slower salt-dependent conformational change, possibly indicative of DNA wrapping, and long (5-15 min) protein-DNA complex lifetimes. We suggest that diverse A3G oligomerization modes contribute to the human immunodeficiency virus, type 1, proviral DNA mutational bias.
Collapse
Affiliation(s)
- Linda Chelico
- Department of Biological Sciences and Chemistry, University of Southern California, Los Angeles, California 90089-2910, USA
| | | | | | | |
Collapse
|
40
|
Sacho EJ, Kadyrov FA, Modrich P, Kunkel TA, Erie DA. Direct visualization of asymmetric adenine-nucleotide-induced conformational changes in MutL alpha. Mol Cell 2008; 29:112-21. [PMID: 18206974 DOI: 10.1016/j.molcel.2007.10.030] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2007] [Revised: 08/15/2007] [Accepted: 10/18/2007] [Indexed: 11/26/2022]
Abstract
MutL alpha, the heterodimeric eukaryotic MutL homolog, is required for DNA mismatch repair (MMR) in vivo. It has been suggested that conformational changes, modulated by adenine nucleotides, mediate the interactions of MutL alpha with other proteins in the MMR pathway, coordinating the recognition of DNA mismatches by MutS alpha and the activation of MutL alpha with the downstream events that lead to repair. Thus far, the only evidence for these conformational changes has come from X-ray crystallography of isolated domains, indirect biochemical analyses, and comparison to other members of the GHL ATPase family to which MutL alpha belongs. Using atomic force microscopy (AFM), coupled with biochemical techniques, we demonstrate that adenine nucleotides induce large asymmetric conformational changes in full-length yeast and human MutL alpha and that these changes are associated with significant increases in secondary structure. These data reveal an ATPase cycle in which sequential nucleotide binding, hydrolysis, and release modulate the conformational states of MutL alpha.
Collapse
Affiliation(s)
- Elizabeth J Sacho
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | | | | | | | | |
Collapse
|
41
|
Sacho EJ, Tessmer I, Diaz M, Erie DA. Response to “Is AID a monomer in solution”. DNA Repair (Amst) 2008. [DOI: 10.1016/j.dnarep.2007.11.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
42
|
Brar SS, Sacho EJ, Tessmer I, Croteau DL, Erie DA, Diaz M. Activation-induced deaminase, AID, is catalytically active as a monomer on single-stranded DNA. DNA Repair (Amst) 2007; 7:77-87. [PMID: 17889624 PMCID: PMC2693009 DOI: 10.1016/j.dnarep.2007.08.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2007] [Revised: 08/03/2007] [Accepted: 08/04/2007] [Indexed: 11/18/2022]
Abstract
Hypermutation and class switch recombination of immunoglobulin genes are antigen-activated mechanisms triggered by AID, a cytidine deaminase. AID deaminates cytidine residues in the DNA of the variable and the switch regions of the immunoglobulin locus. The resulting uracil induces error-prone DNA synthesis in the case of hypermutation or DNA breaks that activate non-homologous recombination in the case of class switch recombination. In vitro studies have demonstrated that AID deaminates single-stranded but not double-stranded substrates unless AID is in a complex with RPA and the substrate is actively undergoing transcription. However, it is not clear whether AID deaminates its substrates primarily as a monomer or as a higher order oligomer. To examine the oligomerization state of AID alone and in the presence of single-stranded DNA substrates of various structures, including loops embedded in double-stranded DNA, we used atomic force microscopy (AFM) to visualize AID protein alone or in complex with DNA. Surprisingly, AFM results indicate that most AID molecules exist as a monomer and that it binds single-stranded DNA substrates as a monomer at concentrations where efficient deamination of single-stranded DNA substrates occur. The rate of deamination, under conditions of excess and limiting protein, also imply that AID can deaminate single-stranded substrates as a monomer. These results imply that non-phosphorylated AID is catalytically active as a monomer on single-stranded DNA in vitro, including single-stranded DNA found in loops similar to those transiently formed in the immunoglobulin switch regions during transcription.
Collapse
Affiliation(s)
- Sukhdev S. Brar
- Laboratory of Molecular Genetics, D3-01, National Institute of Environmental Health, Sciences/National Institutes of Health 111 TW Alexander Drive, Research Triangle Park, NC, 27709, USA
| | - Elizabeth J. Sacho
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Ingrid Tessmer
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Deborah L. Croteau
- Laboratory of Molecular Genetics, D3-01, National Institute of Environmental Health, Sciences/National Institutes of Health 111 TW Alexander Drive, Research Triangle Park, NC, 27709, USA
| | - Dorothy A. Erie
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Curriculum in Applied and Material Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Corresponding authors information: Dr. Marilyn Diaz, Tel. 919-541-4740, Fax, 919-541-7593, E-mail: or Dr. Dorothy Erie, Tel. 919-962-6370, Fax, 919-962-2388, E-mail:
| | - Marilyn Diaz
- Laboratory of Molecular Genetics, D3-01, National Institute of Environmental Health, Sciences/National Institutes of Health 111 TW Alexander Drive, Research Triangle Park, NC, 27709, USA
- Corresponding authors information: Dr. Marilyn Diaz, Tel. 919-541-4740, Fax, 919-541-7593, E-mail: or Dr. Dorothy Erie, Tel. 919-962-6370, Fax, 919-962-2388, E-mail:
| |
Collapse
|
43
|
Abstract
The dsRNA-activated protein kinase, PKR, plays a pivotal role in the cellular antiviral response. PKR contains an N-terminal dsRNA binding domain (dsRBD) and a C-terminal kinase domain. An autoinhibition model has been proposed in which latent PKR exists in a closed conformation where the substrate binding cleft of the kinase is blocked by the dsRBD. Binding to dsRNA activates the enzyme by inducing an open conformation and enhancing dimerization. We have tested this model by characterizing the affinity and kinetics of binding of a nucleotide substrate to PKR. The fluorescent nucleotide mant-AMPPNP binds to unactivated PKR with a Kd of approximately 30 microM, and the affinity is not strongly affected by autophosphorylation or binding to dsRNA. We observe biphasic binding kinetics in which the fast phase depends on ligand concentration but the slow phase is ligand-independent. The kinetic data fit to a two-step model of ligand binding followed by a slow conformation change. The kinetics are also not strongly affected by phosphorylation state or dsRNA binding. Thus, the equilibrium and kinetic data indicate that the substrate accessibility of the kinase is not modulated by PKR activation state as predicted by the autoinhibition model. In atomic force microscopy images, monomers of the latent protein are resolved with three separate regions linked by flexible, bridgelike structures. The resolution of the individual domains in the images supports a model in which unactivated PKR exists in an open conformation where the kinase domain is accessible and capable of binding substrate.
Collapse
Affiliation(s)
- Peter A. Lemaire
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut 06269-3125
| | - Ingrid Tessmer
- Department of Chemistry and Curriculum in Materials and Applied Sciences, University of North Carolina, Chapel Hill, North Carolina 27599-3290
| | - Ranyelle Craig
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut 06269-3125
| | - Dorothy A. Erie
- Department of Chemistry and Curriculum in Materials and Applied Sciences, University of North Carolina, Chapel Hill, North Carolina 27599-3290
| | - James L. Cole
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut 06269-3125
- National Analytical Ultracentrifugation Facility, University of Connecticut, Storrs, Connecticut 06269-3125
- To whom correspondence may be addressed: (860) 486-4333 (telephone),
| |
Collapse
|
44
|
Holmes SF, Santangelo TJ, Cunningham CK, Roberts JW, Erie DA. Kinetic investigation of Escherichia coli RNA polymerase mutants that influence nucleotide discrimination and transcription fidelity. J Biol Chem 2006; 281:18677-83. [PMID: 16621791 DOI: 10.1074/jbc.m600543200] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Recent RNA polymerase (RNAP) structures led to a proposed three-step model of nucleoside triphosphate (NTP) binding, discrimination, and incorporation. NTPs are thought to enter through the secondary channel, bind to an E site, rotate into a pre-insertion (PS) site, and ultimately align in the catalytic (A) site. We characterized the kinetics of correct and incorrect incorporation for several Escherichia coli RNAPs with substitutions in the proposed NTP entry pore (secondary channel). Substitutions of the semi-conserved residue betaAsp(675), which is >10A away from these sites, significantly reduce fidelity; however, substitutions of the totally conserved residues betaArg(678) and betaAsp(814) do not significantly alter the correct or incorrect incorporation kinetics, even though the corresponding residues in RNAPII crystal structures appear to be interacting with the NTP phosphate groups and coordinating the second magnesium ion in the active site, respectively. Structural analysis suggests that the lower fidelity of the betaAsp(675) mutants most likely results from reduction of the negative potential of a small pore between the E and PS sites and elimination of several structural interactions around the pore. We suggest a mechanism of nucleotide discrimination that is governed both by rotation of the NTP through this pore and subsequent rearrangement or closure of RNAP to align the NTP in the A site.
Collapse
Affiliation(s)
- Shannon F Holmes
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599, USA
| | | | | | | | | |
Collapse
|
45
|
Wang H, DellaVecchia MJ, Skorvaga M, Croteau DL, Erie DA, Van Houten B. UvrB domain 4, an autoinhibitory gate for regulation of DNA binding and ATPase activity. J Biol Chem 2006; 281:15227-37. [PMID: 16595666 DOI: 10.1074/jbc.m601476200] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
UvrB, a central DNA damage recognition protein in bacterial nucleotide excision repair, has weak affinity for DNA, and its ATPase activity is activated by UvrA and damaged DNA. Regulation of DNA binding and ATP hydrolysis by UvrB is poorly understood. Using atomic force microscopy and biochemical assays, we found that truncation of domain 4 of Bacillus caldotenax UvrB (UvrBDelta4) leads to multiple changes in protein function. Protein dimerization decreases with an approximately 8-fold increase of the equilibrium dissociation constant and an increase in DNA binding. Loss of domain 4 causes the DNA binding mode of UvrB to change from dimer to monomer, and affinity increases with the apparent dissociation constants on nondamaged and damaged single-stranded DNA decreasing 22- and 14-fold, respectively. ATPase activity by UvrBDelta4 increases 14- and 9-fold with and without single-stranded DNA, respectively, and UvrBDelta4 supports UvrA-independent damage-specific incision by Cho on a bubble DNA substrate. We propose that other than its previously discovered role in regulating protein-protein interactions, domain 4 is an autoinhibitory domain regulating the DNA binding and ATPase activities of UvrB.
Collapse
Affiliation(s)
- Hong Wang
- Laboratory of Molecular Genetics, NIEHS, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina 27709, USA
| | | | | | | | | | | |
Collapse
|
46
|
Lamour V, Hogan BP, Erie DA, Darst SA. Crystal structure of Thermus aquaticus Gfh1, a Gre-factor paralog that inhibits rather than stimulates transcript cleavage. J Mol Biol 2005; 356:179-88. [PMID: 16337964 DOI: 10.1016/j.jmb.2005.10.083] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2005] [Revised: 10/28/2005] [Accepted: 10/30/2005] [Indexed: 11/23/2022]
Abstract
Transcription elongation in bacteria is promoted by Gre-factors, which stimulate an endogenous, endonucleolytic transcript cleavage activity of the RNA polymerase. A GreA paralog, Gfh1, present in Thermus aquaticus and Thermus thermophilus, has the opposite effect on elongation complexes, inhibiting rather than stimulating transcript cleavage. We have determined the 3.3 angstroms-resolution X-ray crystal structure of T.aquaticus Gfh1. The structure reveals an N-terminal and a C-terminal domain with close structural similarity to the domains of GreA, but with an unexpected conformational change in terms of the orientation of the domains with respect to each other. However, structural and functional analysis suggests that when complexed with RNA polymerase, Gfh1 adopts a conformation similar to that of GreA. These results reveal considerable structural flexibility for Gfh1, and for Gre-factors in general, as suggested by structural modeling, and point to a possible role for the conformational switch in Gre-factor and Gfh1 regulation. The opposite functional effect of Gfh1 compared with GreA may be determined by three structural characteristics. First, Gfh1 lacks the basic patch present in Gre-factors that likely plays a role in anchoring the 3'-fragment of the back-tracked RNA. Second, the loop at the tip of the N-terminal coiled-coil is highly flexible and contains extra acidic residues compared with GreA. Third, the N-terminal coiled-coil finger lacks a kink in the first alpha-helix, resulting in a straight coiled-coil compared with GreA. The latter two characteristics suggest that Gfh1 chelates a magnesium ion in the RNA polymerase active site (like GreA) but in a catalytically inactive configuration.
Collapse
MESH Headings
- Amino Acid Sequence
- Bacterial Proteins/chemistry
- Bacterial Proteins/genetics
- Bacterial Proteins/metabolism
- Conserved Sequence
- Crystallography, X-Ray
- DNA-Directed RNA Polymerases/antagonists & inhibitors
- DNA-Directed RNA Polymerases/genetics
- DNA-Directed RNA Polymerases/metabolism
- Gene Expression Regulation, Bacterial
- Molecular Sequence Data
- Protein Structure, Tertiary
- RNA Processing, Post-Transcriptional
- RNA, Bacterial/genetics
- RNA, Bacterial/metabolism
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Sequence Alignment
- Sequence Homology, Amino Acid
- Static Electricity
- Structural Homology, Protein
- Thermus/chemistry
- Thermus/genetics
- Transcription, Genetic
Collapse
Affiliation(s)
- Valerie Lamour
- The Rockefeller University, 1230 York Avenue, New York, NY 10021, USA
| | | | | | | |
Collapse
|
47
|
Abstract
DNA mismatch repair (MMR) is an evolutionarily conserved process that corrects mismatches generated during DNA replication and escape proofreading. MMR proteins also participate in many other DNA transactions, such that inactivation of MMR can have wide-ranging biological consequences, which can be either beneficial or detrimental. We begin this review by briefly considering the multiple functions of MMR proteins and the consequences of impaired function. We then focus on the biochemical mechanism of MMR replication errors. Emphasis is on structure-function studies of MMR proteins, on how mismatches are recognized, on the process by which the newly replicated strand is identified, and on excision of the replication error.
Collapse
Affiliation(s)
- Thomas A Kunkel
- Laboratory of Molecular Genetics and Laboratory of Structural Biology, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709, USA.
| | | |
Collapse
|
48
|
Yang Y, Sass LE, Du C, Hsieh P, Erie DA. Determination of protein-DNA binding constants and specificities from statistical analyses of single molecules: MutS-DNA interactions. Nucleic Acids Res 2005; 33:4322-34. [PMID: 16061937 PMCID: PMC1182163 DOI: 10.1093/nar/gki708] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Atomic force microscopy (AFM) is a powerful technique for examining the conformations of protein–DNA complexes and determining the stoichiometries and affinities of protein–protein complexes. We extend the capabilities of AFM to the determination of protein–DNA binding constants and specificities. The distribution of positions of the protein on the DNA fragments provides a direct measure of specificity and requires no knowledge of the absolute binding constants. The fractional occupancies of the protein at a given position in conjunction with the protein and DNA concentrations permit the determination of the absolute binding constants. We present the theoretical basis for this analysis and demonstrate its utility by characterizing the interaction of MutS with DNA fragments containing either no mismatch or a single mismatch. We show that MutS has significantly higher specificities for mismatches than was previously suggested from bulk studies and that the apparent low specificities are the result of high affinity binding to DNA ends. These results resolve the puzzle of the apparent low binding specificity of MutS with the expected high repair specificities. In conclusion, from a single set of AFM experiments, it is possible to determine the binding affinity, specificity and stoichiometry, as well as the conformational properties of the protein–DNA complexes.
Collapse
Affiliation(s)
- Yong Yang
- Department of Chemistry, University of North Carolina at Chapel HillChapel Hill, NC 27599-3290, USA
| | - Lauryn E. Sass
- Department of Chemistry, University of North Carolina at Chapel HillChapel Hill, NC 27599-3290, USA
| | - Chunwei Du
- Genetics and Biochemistry Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of HealthBethesda, MD 20892, USA
| | - Peggy Hsieh
- Genetics and Biochemistry Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of HealthBethesda, MD 20892, USA
| | - Dorothy A. Erie
- Department of Chemistry, University of North Carolina at Chapel HillChapel Hill, NC 27599-3290, USA
- Curriculum in Applied and Materials Sciences, University of North Carolina at Chapel HillChapel Hill, NC 27599-3290, USA
- To whom correspondence should be addressed. Tel: +1 919 962 6370; Fax: +1 919 966 3675;
| |
Collapse
|
49
|
Tessmer I, Moore T, Lloyd RG, Wilson A, Erie DA, Allen S, Tendler SJB. AFM studies on the role of the protein RdgC in bacterial DNA recombination. J Mol Biol 2005; 350:254-62. [PMID: 15923011 DOI: 10.1016/j.jmb.2005.04.043] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2005] [Revised: 04/04/2005] [Accepted: 04/19/2005] [Indexed: 02/03/2023]
Abstract
Genetic studies of rdgC in different bacterial systems suggest that it may play a role in replication and recombination. However, the exact function of the corresponding protein, RdgC, is unknown. In this study, we have imaged complexes of RdgC with both linear and supercoiled circular plasmid DNA using atomic force microscopy. We confirm that RdgC does not target any specific sequences in double-stranded DNA, as has been suggested from biochemical data. However, we detect an increased affinity of the protein to DNA ends, and an ability to promote bending of DNA. Similar binding preferences have been reported for enzymes involved in recombination. Protein complexes with supercoiled plasmid DNA further enabled us to study the effect of RdgC on DNA superstructure. At high concentrations of protein we observed promotion of DNA condensation. Recombination is largely enhanced by close contacts of distant regions along the DNA strands, as can occur, for instance, through condensation. Our data thus support a possible function of RdgC as a midwife of recombination.
Collapse
MESH Headings
- DNA, Bacterial/chemistry
- DNA, Bacterial/genetics
- DNA, Bacterial/metabolism
- DNA, Bacterial/ultrastructure
- DNA, Superhelical/chemistry
- DNA, Superhelical/genetics
- DNA, Superhelical/metabolism
- DNA, Superhelical/ultrastructure
- Escherichia coli Proteins/chemistry
- Escherichia coli Proteins/metabolism
- Escherichia coli Proteins/ultrastructure
- Microscopy, Atomic Force
- Nucleic Acid Conformation
- Plasmids/chemistry
- Plasmids/genetics
- Plasmids/metabolism
- Plasmids/ultrastructure
- Protein Structure, Quaternary
- Recombination, Genetic
Collapse
Affiliation(s)
- Ingrid Tessmer
- Laboratory of Biophysics and Surface Analysis, School of Pharmacy, University of Nottingham, Nottingham NG7 2RD, UK
| | | | | | | | | | | | | |
Collapse
|
50
|
Brenowitz M, Erie DA, Chance MR. Catching RNA polymerase in the act of binding: intermediates in transcription illuminated by synchrotron footprinting. Proc Natl Acad Sci U S A 2005; 102:4659-60. [PMID: 15781859 PMCID: PMC555728 DOI: 10.1073/pnas.0501152102] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Michael Brenowitz
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
| | | | | |
Collapse
|