1
|
Puelles JS, Ghorbani M, Tuck B, Machuca LL, Ackland ML, Chen F, Somers AE, Forsyth M. Effect of cetrimonium carrier micelles on bacterial membranes and extracellular DNA, an in silico study. Sci Rep 2023; 13:8041. [PMID: 37198168 DOI: 10.1038/s41598-023-32475-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Accepted: 03/28/2023] [Indexed: 05/19/2023] Open
Abstract
Microorganisms do not live as dispersed single cells but rather they form aggregates with extracellular polymeric substances at interfaces. Biofilms are considered efficient life forms because they shield bacteria from biocides and collect dilute nutrients. This is a big concern in industry since the microorganisms can colonize a wide range of surfaces, accelerating material deterioration, colonizing medical devices, contaminating ultrapure drinking water, increasing energy costs and creating focus of infection. Conventional biocides that target a specific component of the bacteria are not effective in the presence of biofilms. Efficient biofilm inhibitors are based on a multitarget approach interacting with the bacteria and the biofilm matrix. Their rationale design requires a thorough understanding of inhibitory mechanisms that are still largely lacking today. Herein we uncover via molecular modelling the inhibition mechanism of cetrimonium 4-OH cinnamate (CTA-4OHcinn). Simulations show that CTA-4OH micelles can disrupt symmetric and asymmetric bilayers, representative of inner and outer bacterial membranes, following three stages: adsorption, assimilation, and defect formation. The main driving force for micellar attack is electrostatic interactions. In addition to disrupting the bilayers, the micelles work as carriers facilitating the trapping of 4OH cinnamate anions within the bilayer upper leaflet and overcoming electrostatic repulsion. The micelles also interact with extracellular DNA (e-DNA), which is one of the main components of biofilms. It is observed that CTA-4OHcinn forms spherical micelles on the DNA backbone; which hinders their ability to pack. This is demonstrated by modelling the DNA along the hbb histone-like protein, showing that in the presence of CTA-4OHcinn, DNA does not pack properly around hbb. The abilities of CTA-4OHcinn to cause cell death through membrane disruption and to disperse a mature, multi-species biofilm are also confirmed experimentally.
Collapse
Affiliation(s)
| | - Mahdi Ghorbani
- Institute for Frontier Materials, Deakin University, Geelong, VIC, 3217, Australia
| | - Benjamin Tuck
- Curtin Corrosion Centre, WA School of Mines: Minerals, Energy and Chemical Engineering, Curtin University, Kent Street, Bentley, WA, 6102, Australia
| | - Laura L Machuca
- Curtin Corrosion Centre, WA School of Mines: Minerals, Energy and Chemical Engineering, Curtin University, Kent Street, Bentley, WA, 6102, Australia
| | - M Leigh Ackland
- ARC Centre of Excellence for Electromaterials Science (ACES), Deakin University, Burwood, 3125, Australia
- School of Life and Environmental Sciences, Deakin University, Burwood, Victoria, 3125, Australia
| | - Fangfang Chen
- Institute for Frontier Materials, Deakin University, Geelong, VIC, 3217, Australia.
- ARC Centre of Excellence for Electromaterials Science (ACES), Deakin University, Burwood, 3125, Australia.
| | - Anthony E Somers
- Institute for Frontier Materials, Deakin University, Geelong, VIC, 3217, Australia.
| | - Maria Forsyth
- Institute for Frontier Materials, Deakin University, Geelong, VIC, 3217, Australia.
- ARC Centre of Excellence for Electromaterials Science (ACES), Deakin University, Burwood, 3125, Australia.
| |
Collapse
|
2
|
Santiago-Frangos A, Buyukyoruk M, Wiegand T, Krishna P, Wiedenheft B. Distribution and phasing of sequence motifs that facilitate CRISPR adaptation. Curr Biol 2021; 31:3515-3524.e6. [PMID: 34174210 PMCID: PMC8552246 DOI: 10.1016/j.cub.2021.05.068] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 04/30/2021] [Accepted: 05/28/2021] [Indexed: 12/11/2022]
Abstract
CRISPR-associated proteins (Cas1 and Cas2) integrate foreign DNA at the "leader" end of CRISPR loci. Several CRISPR leader sequences are reported to contain a binding site for a DNA-bending protein called integration host factor (IHF). IHF-induced DNA bending kinks the leader of type I-E CRISPRs, recruiting an upstream sequence motif that helps dock Cas1-2 onto the first repeat of the CRISPR locus. To determine the prevalence of IHF-directed CRISPR adaptation, we analyzed 15,274 bacterial and archaeal CRISPR leaders. These experiments reveal multiple IHF binding sites and diverse upstream sequence motifs in a subset of the I-C, I-E, I-F, and II-C CRISPR leaders. We identify subtype-specific motifs and show that the phase of these motifs is critical for CRISPR adaptation. Collectively, this work clarifies the prevalence and mechanism(s) of IHF-dependent CRISPR adaptation and suggests that leader sequences and adaptation proteins may coevolve under the selective pressures of foreign genetic elements like plasmids or phages.
Collapse
Affiliation(s)
| | - Murat Buyukyoruk
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA
| | - Tanner Wiegand
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA
| | - Pushya Krishna
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA
| | - Blake Wiedenheft
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA.
| |
Collapse
|
3
|
Kamagata K, Itoh Y, Tan C, Mano E, Wu Y, Mandali S, Takada S, Johnson RC. Testing mechanisms of DNA sliding by architectural DNA-binding proteins: dynamics of single wild-type and mutant protein molecules in vitro and in vivo. Nucleic Acids Res 2021; 49:8642-8664. [PMID: 34352099 PMCID: PMC8421229 DOI: 10.1093/nar/gkab658] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 07/10/2021] [Accepted: 07/22/2021] [Indexed: 01/06/2023] Open
Abstract
Architectural DNA-binding proteins (ADBPs) are abundant constituents of eukaryotic or bacterial chromosomes that bind DNA promiscuously and function in diverse DNA reactions. They generate large conformational changes in DNA upon binding yet can slide along DNA when searching for functional binding sites. Here we investigate the mechanism by which ADBPs diffuse on DNA by single-molecule analyses of mutant proteins rationally chosen to distinguish between rotation-coupled diffusion and DNA surface sliding after transient unbinding from the groove(s). The properties of yeast Nhp6A mutant proteins, combined with molecular dynamics simulations, suggest Nhp6A switches between two binding modes: a static state, in which the HMGB domain is bound within the minor groove with the DNA highly bent, and a mobile state, where the protein is traveling along the DNA surface by means of its flexible N-terminal basic arm. The behaviors of Fis mutants, a bacterial nucleoid-associated helix-turn-helix dimer, are best explained by mobile proteins unbinding from the major groove and diffusing along the DNA surface. Nhp6A, Fis, and bacterial HU are all near exclusively associated with the chromosome, as packaged within the bacterial nucleoid, and can be modeled by three diffusion modes where HU exhibits the fastest and Fis the slowest diffusion.
Collapse
Affiliation(s)
- Kiyoto Kamagata
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577, Japan
| | - Yuji Itoh
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577, Japan
| | - Cheng Tan
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Eriko Mano
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577, Japan
| | - Yining Wu
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577, Japan
| | - Sridhar Mandali
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095-1737, USA
| | - Shoji Takada
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Reid C Johnson
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095-1737, USA.,Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
| |
Collapse
|
4
|
Clauvelin N, Olson WK. Synergy between Protein Positioning and DNA Elasticity: Energy Minimization of Protein-Decorated DNA Minicircles. J Phys Chem B 2021; 125:2277-2287. [DOI: 10.1021/acs.jpcb.0c11612] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Nicolas Clauvelin
- Center for Quantitative Biology and Department of Chemistry and Chemical Biology, Rutgers, the State University of New Jersey, Piscataway, New Jersey 08854, United States
| | - Wilma K. Olson
- Center for Quantitative Biology and Department of Chemistry and Chemical Biology, Rutgers, the State University of New Jersey, Piscataway, New Jersey 08854, United States
| |
Collapse
|
5
|
Samuels DS, Lybecker MC, Yang XF, Ouyang Z, Bourret TJ, Boyle WK, Stevenson B, Drecktrah D, Caimano MJ. Gene Regulation and Transcriptomics. Curr Issues Mol Biol 2020; 42:223-266. [PMID: 33300497 DOI: 10.21775/cimb.042.223] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Borrelia (Borreliella) burgdorferi, along with closely related species, is the etiologic agent of Lyme disease. The spirochete subsists in an enzootic cycle that encompasses acquisition from a vertebrate host to a tick vector and transmission from a tick vector to a vertebrate host. To adapt to its environment and persist in each phase of its enzootic cycle, B. burgdorferi wields three systems to regulate the expression of genes: the RpoN-RpoS alternative sigma factor cascade, the Hk1/Rrp1 two-component system and its product c-di-GMP, and the stringent response mediated by RelBbu and DksA. These regulatory systems respond to enzootic phase-specific signals and are controlled or fine- tuned by transcription factors, including BosR and BadR, as well as small RNAs, including DsrABb and Bb6S RNA. In addition, several other DNA-binding and RNA-binding proteins have been identified, although their functions have not all been defined. Global changes in gene expression revealed by high-throughput transcriptomic studies have elucidated various regulons, albeit technical obstacles have mostly limited this experimental approach to cultivated spirochetes. Regardless, we know that the spirochete, which carries a relatively small genome, regulates the expression of a considerable number of genes required for the transitions between the tick vector and the vertebrate host as well as the adaptation to each.
Collapse
Affiliation(s)
- D Scott Samuels
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA
| | - Meghan C Lybecker
- Department of Biology, University of Colorado, Colorado Springs, CO 80918, USA
| | - X Frank Yang
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Zhiming Ouyang
- Department of Molecular Medicine, University of South Florida, Tampa, FL 33612, USA
| | - Travis J Bourret
- Department of Medical Microbiology and Immunology, Creighton University, Omaha, NE, 68105 USA
| | - William K Boyle
- Department of Medical Microbiology and Immunology, Creighton University, Omaha, NE, 68105 USA
| | - Brian Stevenson
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky School of Medicine, Lexington, KY 40536, USA
| | - Dan Drecktrah
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA
| | - Melissa J Caimano
- Departments of Medicine, Pediatrics, and Molecular Biology and Biophysics, UConn Health, Farmington, CT, USA
| |
Collapse
|
6
|
Agapova YK, Altukhov DA, Kamashev DE, Timofeev VI, Smirnova EV, Rakitina TV. Inhibitor Targeting the Interface between Monomers of HU Protein from Spiroplasma melliferum Disrupts Conformational Dynamics and DNA-Binding Properties of the Protein. CRYSTALLOGR REP+ 2020. [DOI: 10.1134/s1063774520060048] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
7
|
Chen SWW, Banneville AS, Teulon JM, Timmins J, Pellequer JL. Nanoscale surface structures of DNA bound to Deinococcus radiodurans HU unveiled by atomic force microscopy. NANOSCALE 2020; 12:22628-22638. [PMID: 33150905 DOI: 10.1039/d0nr05320a] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The Deinococcus radiodurans protein HU (DrHU) was shown to be critical for nucleoid activities, yet its functional and structural properties remain largely unexplored. We have applied atomic force microscopy (AFM) imaging to study DrHU binding to pUC19-DNA in vitro and analyzed the topographic structures formed at the nanoscale. At the single-molecule level, AFM imaging allows visualization of super-helical turns on naked DNA surfaces and characterization of free DrHU molecules observed as homodimers. When enhancing the molecular surface structures of AFM images by the Laplacian weight filter, the distribution of bound DrHUs was visibly varied as a function of the DrHU/DNA molar ratio. At a low molar ratio, DrHU binding was found to reduce the volume of condensed DNA configuration by about 50%. We also show that DrHU is capable of bridging distinct DNA segments. Moreover, at a low molar ratio, the binding orientation of individual DrHU dimers could be perceived on partially "open" DNA configuration. At a high molar ratio, DrHU stiffened the DNA molecule and enlarged the spread of the open DNA configuration. Furthermore, a lattice-like pattern could be seen on the surface of DrHU-DNA complex, indicating that DrHU multimerization had occurred leading to the formation of a higher order architecture. Together, our results show that the functional plasticity of DrHU in mediating DNA organization is subject to both the conformational dynamics of DNA molecules and protein abundance.
Collapse
Affiliation(s)
- Shu-Wen W Chen
- Univ. Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale (IBS), F-38000 Grenoble, France.
| | | | | | | | | |
Collapse
|
8
|
Structure-based inhibitors targeting the alpha-helical domain of the Spiroplasma melliferum histone-like HU protein. Sci Rep 2020; 10:15128. [PMID: 32934267 PMCID: PMC7493962 DOI: 10.1038/s41598-020-72113-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 08/25/2020] [Indexed: 11/30/2022] Open
Abstract
Here we report bisphenol derivatives of fluorene (BDFs) as a new type of chemical probes targeting a histone-like HU protein, a global regulator of bacterial nucleoids, via its dimerization interface perturbation. BDFs were identified by virtual screening and molecular docking that targeted the core of DNA-binding β-saddle-like domain of the HU protein from Spiroplasma melliferum. However, NMR spectroscopy, complemented with molecular dynamics and site-directed mutagenesis, indicated that the actual site of the inhibitors’ intervention consists of residues from the α-helical domain of one monomer and the side portion of the DNA-binding domain of another monomer. BDFs inhibited DNA-binding properties of HU proteins from mycoplasmas S. melliferum, Mycoplasma gallicepticum and Escherichia coli with half-maximum inhibitory concentrations in the range between 5 and 10 µM. In addition, BDFs demonstrated antimicrobial activity against mycoplasma species, but not against E. coli, which is consistent with the compensatory role of other nucleoid-associated proteins in the higher bacteria. Further evaluation of antimicrobial effects of BDFs against various bacteria and viruses will reveal their pharmacological potential, and the allosteric inhibition mode reported here, which avoids direct competition for the binding site with DNA, should be considered in the development of small molecule inhibitors of nucleoid-associated proteins as well as other types of DNA-binding multimeric proteins.
Collapse
|
9
|
The structural basis of African swine fever virus pA104R binding to DNA and its inhibition by stilbene derivatives. Proc Natl Acad Sci U S A 2020; 117:11000-11009. [PMID: 32358196 DOI: 10.1073/pnas.1922523117] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
African swine fever virus (ASFV) is a highly contagious nucleocytoplasmic large DNA virus (NCLDV) that causes nearly 100% mortality in swine. The development of effective vaccines and drugs against this virus is urgently needed. pA104R, an ASFV-derived histone-like protein, shares sequence and functional similarity with bacterial HU/IHF family members and is essential for viral replication. Herein, we solved the crystal structures of pA104R in its apo state as well as in complex with DNA. Apo-pA104R forms a homodimer and folds into an architecture conserved in bacterial heat-unstable nucleoid proteins/integration host factors (HUs/IHFs). The pA104R-DNA complex structure, however, uncovers that pA104R has a DNA binding pattern distinct from its bacterial homologs, that is, the β-ribbon arms of pA104R stabilize DNA binding by contacting the major groove instead of the minor groove. Mutations of the basic residues at the base region of the β-strand DNA binding region (BDR), rather than those in the β-ribbon arms, completely abolished DNA binding, highlighting the major role of the BDR base in DNA binding. An overall DNA bending angle of 93.8° is observed in crystal packing of the pA104R-DNA complex structure, which is close to the DNA bending angle in the HU-DNA complex. Stilbene derivatives SD1 and SD4 were shown to disrupt the binding between pA104R and DNA and inhibit the replication of ASFV in primary porcine alveolar macrophages. Collectively, these results reveal the structural basis of pA104R binding to DNA highlighting the importance of the pA104R-DNA interaction in the ASFV replication cycle and provide inhibitor leads for ASFV chemotherapy.
Collapse
|
10
|
Georgoulis A, Louka M, Mylonas S, Stavros P, Nounesis G, Vorgias CE. Consensus protein engineering on the thermostable histone-like bacterial protein HUs significantly improves stability and DNA binding affinity. Extremophiles 2020; 24:293-306. [PMID: 31980943 DOI: 10.1007/s00792-020-01154-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 01/06/2020] [Indexed: 11/28/2022]
Abstract
Consensus-based protein engineering strategy has been applied to various proteins and it can lead to the design of proteins with enhanced biological performance. Histone-like HUs comprise a protein family with sequence variety within a highly conserved 3D-fold. HU function includes compacting and regulating bacterial DNA in a wide range of biological conditions in bacteria. To explore the possible impact of consensus-based design in the thermodynamic stability of HU proteins, the approach was applied using a dataset of sequences derived from a group of 40 mesostable, thermostable, and hyperthermostable HUs. The consensus-derived HU protein was named HUBest, since it is expected to perform best. The synthetic HU gene was overexpressed in E. coli and the recombinant protein was purified. Subsequently, HUBest was characterized concerning its correct folding and thermodynamic stability, as well as its ability to interact with plasmid DNA. A substantial increase in HUBest stability at high temperatures is observed. HUBest has significantly improved biological performance at ambience temperature, presenting very low Kd values for binding plasmid DNA as indicated from the Gibbs energy profile of HUBest. This Kd may be associated to conformational changes leading to decreased thermodynamic stability and, therefore, higher flexibility at ambient temperature.
Collapse
Affiliation(s)
- Anastasios Georgoulis
- Department of Biochemistry and Molecular Biology, National and Kapodistrian University of Athens, 157 01, Zografou, Greece
| | - Maria Louka
- Department of Biochemistry and Molecular Biology, National and Kapodistrian University of Athens, 157 01, Zografou, Greece
| | - Stratos Mylonas
- Department of Biochemistry and Molecular Biology, National and Kapodistrian University of Athens, 157 01, Zografou, Greece
| | - Philemon Stavros
- Biomolecular Physics Laboratory, INRASTES, National Centre for Scientific Research "Demokritos", 153 10, Agia Paraskevi, Greece
| | - George Nounesis
- Biomolecular Physics Laboratory, INRASTES, National Centre for Scientific Research "Demokritos", 153 10, Agia Paraskevi, Greece
| | - Constantinos E Vorgias
- Department of Biochemistry and Molecular Biology, National and Kapodistrian University of Athens, 157 01, Zografou, Greece.
| |
Collapse
|
11
|
Hognon C, Garaude S, Timmins J, Chipot C, Dehez F, Monari A. Molecular Bases of DNA Packaging in Bacteria Revealed by All-Atom Molecular Dynamics Simulations: The Case of Histone-Like Proteins in Borrelia burgdorferi. J Phys Chem Lett 2019; 10:7200-7207. [PMID: 31693374 DOI: 10.1021/acs.jpclett.9b02978] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
DNA compaction is essential to ensure the packaging of the genetic material in living cells and also plays a key role in the epigenetic regulation of gene expression. In both humans and bacteria, DNA packaging is achieved by specific well-conserved proteins. Here, by means of all-atom molecular dynamics simulations, including the determination of relevant free-energy profiles, we rationalize the molecular bases for this remarkable process in bacteria, illustrating the crucial role played by positively charged amino acids of a small histone-like protein. We also present compelling evidence that this histone-like protein alone can induce strong bending of a DNA duplex around its core domain, a process that requires overcoming a major free-energy barrier.
Collapse
Affiliation(s)
- Cécilia Hognon
- Université de Lorraine and CNRS, LPCT UMR 7019 , F-54000 Nancy , France
| | - Simon Garaude
- Université de Lorraine and CNRS, LPCT UMR 7019 , F-54000 Nancy , France
| | - Joanna Timmins
- Université Grenoble Alpes , CNRS, CEA, IBS , F-38000 Grenoble , France
| | - Christophe Chipot
- Université de Lorraine and CNRS, LPCT UMR 7019 , F-54000 Nancy , France
- Department of Physics , University of Illinois at Urbana-Champaign , 1110 West Green Street , Urbana , Illinois 61801 , United States
- Laboratoire International Associé Centre National de la Recherche Scientifique et University of Illinois at Urbana-Champaign , 54506 Vandoeuvre-lès-Nancy Cedex, France
| | - François Dehez
- Université de Lorraine and CNRS, LPCT UMR 7019 , F-54000 Nancy , France
- Laboratoire International Associé Centre National de la Recherche Scientifique et University of Illinois at Urbana-Champaign , 54506 Vandoeuvre-lès-Nancy Cedex, France
| | - Antonio Monari
- Université de Lorraine and CNRS, LPCT UMR 7019 , F-54000 Nancy , France
| |
Collapse
|
12
|
Loth K, Largillière J, Coste F, Culard F, Landon C, Castaing B, Delmas AF, Paquet F. New protein-DNA complexes in archaea: a small monomeric protein induces a sharp V-turn DNA structure. Sci Rep 2019; 9:14253. [PMID: 31582767 PMCID: PMC6776556 DOI: 10.1038/s41598-019-50211-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 09/05/2019] [Indexed: 01/02/2023] Open
Abstract
MC1, a monomeric nucleoid-associated protein (NAP), is structurally unrelated to other DNA-binding proteins. The protein participates in the genome organization of several Euryarchaea species through an atypical compaction mechanism. It is also involved in DNA transcription and cellular division through unknown mechanisms. We determined the 3D solution structure of a new DNA-protein complex formed by MC1 and a strongly distorted 15 base pairs DNA. While the protein just needs to adapt its conformation slightly, the DNA undergoes a dramatic curvature (the first two bend angles of 55° and 70°, respectively) and an impressive torsional stress (dihedral angle of 106°) due to several kinks upon binding of MC1 to its concave side. Thus, it adopts a V-turn structure. For longer DNAs, MC1 stabilizes multiple V-turn conformations in a flexible and dynamic manner. The existence of such V-turn conformations of the MC1-DNA complexes leads us to propose two binding modes of the protein, as a bender (primary binding mode) and as a wrapper (secondary binding mode). Moreover, it opens up new opportunities for studying and understanding the repair, replication and transcription molecular machineries of Archaea.
Collapse
Affiliation(s)
- Karine Loth
- Centre de Biophysique Moléculaire, Centre National de la Recherche Scientifique UPR 4301, rue Charles Sadron, F-45071, Orléans, Cedex 2, France. .,UFR Collegium Sciences et Techniques, Université d'Orléans, rue de Chartres, 45100, Orléans, France.
| | - Justine Largillière
- Centre de Biophysique Moléculaire, Centre National de la Recherche Scientifique UPR 4301, rue Charles Sadron, F-45071, Orléans, Cedex 2, France
| | - Franck Coste
- Centre de Biophysique Moléculaire, Centre National de la Recherche Scientifique UPR 4301, rue Charles Sadron, F-45071, Orléans, Cedex 2, France
| | - Françoise Culard
- Centre de Biophysique Moléculaire, Centre National de la Recherche Scientifique UPR 4301, rue Charles Sadron, F-45071, Orléans, Cedex 2, France
| | - Céline Landon
- Centre de Biophysique Moléculaire, Centre National de la Recherche Scientifique UPR 4301, rue Charles Sadron, F-45071, Orléans, Cedex 2, France
| | - Bertrand Castaing
- Centre de Biophysique Moléculaire, Centre National de la Recherche Scientifique UPR 4301, rue Charles Sadron, F-45071, Orléans, Cedex 2, France
| | - Agnès F Delmas
- Centre de Biophysique Moléculaire, Centre National de la Recherche Scientifique UPR 4301, rue Charles Sadron, F-45071, Orléans, Cedex 2, France
| | - Françoise Paquet
- Centre de Biophysique Moléculaire, Centre National de la Recherche Scientifique UPR 4301, rue Charles Sadron, F-45071, Orléans, Cedex 2, France.
| |
Collapse
|
13
|
Zhou H, Sathyamoorthy B, Stelling A, Xu Y, Xue Y, Pigli YZ, Case DA, Rice PA, Al-Hashimi HM. Characterizing Watson-Crick versus Hoogsteen Base Pairing in a DNA-Protein Complex Using Nuclear Magnetic Resonance and Site-Specifically 13C- and 15N-Labeled DNA. Biochemistry 2019; 58:1963-1974. [PMID: 30950607 DOI: 10.1021/acs.biochem.9b00027] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
A( syn)-T and G( syn)-C+ Hoogsteen base pairs in protein-bound DNA duplexes can be difficult to resolve by X-ray crystallography due to ambiguous electron density and by nuclear magnetic resonance (NMR) spectroscopy due to poor chemical shift dispersion and size limitations with solution-state NMR spectroscopy. Here we describe an NMR strategy for characterizing Hoogsteen base pairs in protein-DNA complexes, which relies on site-specifically incorporating 13C- and 15N-labeled nucleotides into DNA duplexes for unambiguous resonance assignment and to improve spectral resolution. The approach was used to resolve the conformation of an A-T base pair in a crystal structure of an ∼43 kDa complex between a 34 bp duplex DNA and the integration host factor (IHF) protein. In the crystal structure (Protein Data Bank entry 1IHF ), this base pair adopts an unusual Hoogsteen conformation with a distorted sugar backbone that is accommodated by a nearby nick used to aid in crystallization. The NMR chemical shifts and interproton nuclear Overhauser effects indicate that this base pair predominantly adopts a Watson-Crick conformation in the intact DNA-IHF complex under solution conditions. Consistent with these NMR findings, substitution of 7-deazaadenine at this base pair resulted in only a small (∼2-fold) decrease in the IHF-DNA binding affinity. The NMR strategy provides a new approach for resolving crystallographic ambiguity and more generally for studying the structure and dynamics of protein-DNA complexes in solution.
Collapse
Affiliation(s)
- Huiqing Zhou
- Department of Biochemistry , Duke University School of Medicine , Durham , North Carolina 27710 , United States
| | - Bharathwaj Sathyamoorthy
- Department of Chemistry , Indian Institute of Science Education and Research Bhopal , Bhopal 462066 , India
| | - Allison Stelling
- Department of Biochemistry , Duke University School of Medicine , Durham , North Carolina 27710 , United States
| | - Yu Xu
- Department of Chemistry , Duke University , Durham , North Carolina 27708 , United States
| | - Yi Xue
- Tsinghua-Peking Center for Life Sciences, School of Life Sciences , Tsinghua University , Beijing 100084 , China
| | - Ying Zhang Pigli
- Biochemistry and Molecular Biology , The University of Chicago , Chicago , Illinois 60637 , United States
| | - David A Case
- Department of Chemistry and Chemical Biology , Rutgers University , Piscataway , New Jersey 08854 , United States
| | - Phoebe A Rice
- Biochemistry and Molecular Biology , The University of Chicago , Chicago , Illinois 60637 , United States
| | - Hashim M Al-Hashimi
- Department of Biochemistry , Duke University School of Medicine , Durham , North Carolina 27710 , United States.,Department of Chemistry , Duke University , Durham , North Carolina 27708 , United States
| |
Collapse
|
14
|
Oliveira Paiva AM, Friggen AH, Qin L, Douwes R, Dame RT, Smits WK. The Bacterial Chromatin Protein HupA Can Remodel DNA and Associates with the Nucleoid in Clostridium difficile. J Mol Biol 2019; 431:653-672. [PMID: 30633871 DOI: 10.1016/j.jmb.2019.01.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 12/19/2018] [Accepted: 01/02/2019] [Indexed: 12/15/2022]
Abstract
The maintenance and organization of the chromosome plays an important role in the development and survival of bacteria. Bacterial chromatin proteins are architectural proteins that bind DNA and modulate its conformation, and by doing so affect a variety of cellular processes. No bacterial chromatin proteins of Clostridium difficile have been characterized to date. Here, we investigate aspects of the C. difficile HupA protein, a homologue of the histone-like HU proteins of Escherichia coli. HupA is a 10-kDa protein that is present as a homodimer in vitro and self-interacts in vivo. HupA co-localizes with the nucleoid of C. difficile. It binds to the DNA without a preference for the DNA G + C content. Upon DNA binding, HupA induces a conformational change in the substrate DNA in vitro and leads to compaction of the chromosome in vivo. The present study is the first to characterize a bacterial chromatin protein in C. difficile and opens the way to study the role of chromosomal organization in DNA metabolism and on other cellular processes in this organism.
Collapse
Affiliation(s)
- Ana M Oliveira Paiva
- Department of Medical Microbiology, Section Experimental Bacteriology, Leiden University Medical Center, Leiden, the Netherlands; Center for Microbial Cell Biology, Leiden, the Netherlands
| | - Annemieke H Friggen
- Department of Medical Microbiology, Section Experimental Bacteriology, Leiden University Medical Center, Leiden, the Netherlands; Center for Microbial Cell Biology, Leiden, the Netherlands
| | - Liang Qin
- Faculty of Science, Leiden Institute of Chemistry, Leiden University, Leiden, the Netherlands; Center for Microbial Cell Biology, Leiden, the Netherlands
| | - Roxanne Douwes
- Department of Medical Microbiology, Section Experimental Bacteriology, Leiden University Medical Center, Leiden, the Netherlands
| | - Remus T Dame
- Faculty of Science, Leiden Institute of Chemistry, Leiden University, Leiden, the Netherlands; Center for Microbial Cell Biology, Leiden, the Netherlands
| | - Wiep Klaas Smits
- Department of Medical Microbiology, Section Experimental Bacteriology, Leiden University Medical Center, Leiden, the Netherlands; Center for Microbial Cell Biology, Leiden, the Netherlands.
| |
Collapse
|
15
|
Connolly M, Arra A, Zvoda V, Steinbach PJ, Rice PA, Ansari A. Static Kinks or Flexible Hinges: Multiple Conformations of Bent DNA Bound to Integration Host Factor Revealed by Fluorescence Lifetime Measurements. J Phys Chem B 2018; 122:11519-11534. [DOI: 10.1021/acs.jpcb.8b07405] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Mitchell Connolly
- Department of Physics, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Aline Arra
- Department of Physics, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Viktoriya Zvoda
- Department of Physics, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Peter J. Steinbach
- Center for Molecular Modeling, Center for Information Technology, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Phoebe A. Rice
- Department of Biochemistry & Molecular Biology, University of Chicago, Chicago, Illinois 60637, United States
| | - Anjum Ansari
- Department of Physics, University of Illinois at Chicago, Chicago, Illinois 60607, United States
- Department of Bioengineering, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| |
Collapse
|
16
|
Abstract
Borrelia burgdorferi HtrA (HtrABb) is a serine protease that targets damaged or improperly folded proteins. In our previous studies, HtrABb specifically degraded basic membrane protein BmpD, chemotaxis phosphatase CheX, and outer membrane protein P66. In addition, HtrABb degrades virulence factor BB0323 and components of the extracellular matrix fibronectin and aggrecan. A proteomics-based analysis (two-dimensional difference gel electrophoresis [2-D DIGE], liquid chromatography-mass spectrometry [LC-MS]) of an HtrABb-overexpressing strain of B. burgdorferi (A3HtrAOE) revealed that protein levels of P66 were reduced in comparison to wild-type B. burgdorferi, confirming its status as an HtrABb substrate. Hbb, a P66-DNA-binding transcription factor, was specifically degraded by HtrABb, providing supportive evidence for a role for both in the regulation of P66. A3HtrAOE exhibited reduced motility in swarm assays, a possible link between overabundance of HtrABb and its enzymatic specificity for P66. However, the ΔP66 strain did not have reduced motility in the swarm assays, negating a role for this protein. The proteomics analyses also identified three enzymes of the glycolytic pathway, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), glycerol-3-phosphate dehydrogenase (GPDH), and glycerol kinase (GK), and one enzyme involved in carbohydrate metabolism, diphosphate-fructose-6-phosphate 1-phosphotransferase, which were reduced in A3HtrAOE. Consistent with its reduced protein levels of these glycolytic enzymes, A3HtrAOE was also deficient in production of pyruvate. We propose a model for a role for HtrABb in contributing to a decrease in metabolic activity of B. burgdorferi. Being a vector-borne bacterium, B. burgdorferi must remodel its protein content as it transfers from tick to mammal. Proteolysis is a mechanism whereby remodeling can be accomplished. HtrABb degrades a number of proteins whose disappearance may help in preparing this organism for a stage of low metabolic activity.
Collapse
|
17
|
Nguyen H, Pham T, Nguyen HL, Phan T. Investigation of Binding Affinity Between Prokaryotic Proteins (AHU-IHF) and DNAs: Steered Molecular Dynamics Approach. Appl Biochem Biotechnol 2018; 186:834-846. [DOI: 10.1007/s12010-018-2735-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 03/12/2018] [Indexed: 11/29/2022]
|
18
|
Trussart M, Yus E, Martinez S, Baù D, Tahara YO, Pengo T, Widjaja M, Kretschmer S, Swoger J, Djordjevic S, Turnbull L, Whitchurch C, Miyata M, Marti-Renom MA, Lluch-Senar M, Serrano L. Defined chromosome structure in the genome-reduced bacterium Mycoplasma pneumoniae. Nat Commun 2017; 8:14665. [PMID: 28272414 PMCID: PMC5344976 DOI: 10.1038/ncomms14665] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 01/20/2017] [Indexed: 12/24/2022] Open
Abstract
DNA-binding proteins are central regulators of chromosome organization; however, in genome-reduced bacteria their diversity is largely diminished. Whether the chromosomes of such bacteria adopt defined three-dimensional structures remains unexplored. Here we combine Hi-C and super-resolution microscopy to determine the structure of the Mycoplasma pneumoniae chromosome at a 10 kb resolution. We find a defined structure, with a global symmetry between two arms that connect opposite poles, one bearing the chromosomal Ori and the other the midpoint. Analysis of local structures at a 3 kb resolution indicates that the chromosome is organized into domains ranging from 15 to 33 kb. We provide evidence that genes within the same domain tend to be co-regulated, suggesting that chromosome organization influences transcriptional regulation, and that supercoiling regulates local organization. This study extends the current understanding of bacterial genome organization and demonstrates that a defined chromosomal structure is a universal feature of living systems.
Collapse
Affiliation(s)
- Marie Trussart
- EMBL/CRG Systems Biology Research Unit, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr Aiguader 88, Barcelona 08003, Spain.,Universitat Pompeu Fabra (UPF), 08003 Barcelona, Spain
| | - Eva Yus
- EMBL/CRG Systems Biology Research Unit, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr Aiguader 88, Barcelona 08003, Spain.,Universitat Pompeu Fabra (UPF), 08003 Barcelona, Spain
| | - Sira Martinez
- EMBL/CRG Systems Biology Research Unit, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr Aiguader 88, Barcelona 08003, Spain
| | - Davide Baù
- Gene Regulation, Stem Cells and Cancer Program. Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr Aiguader 88, Barcelona 08003, Spain.,CNAG-CRG, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Baldiri Reixac 4, Barcelona 08028, Spain
| | - Yuhei O Tahara
- Department of Biology, Graduate School of Science, Osaka City University, 558-8585 Osaka, Japan.,OCU Advanced Research Institute for Natural Science and Technology (OCARNA), Osaka City University, 558-8585 Osaka, Japan
| | - Thomas Pengo
- EMBL/CRG Systems Biology Research Unit, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr Aiguader 88, Barcelona 08003, Spain.,Advanced Light Microscopy Unit, Centre for Genomic Regulation (CRG), 08003 Barcelona, Spain
| | - Michael Widjaja
- The ithree Institute, The University of Technology Sydney, Sydney, New South Wales 2007, Australia
| | - Simon Kretschmer
- Department of Cellular and Molecular Biophysics, Max Planck Institute of Biochemistry, 82152, Martinsried, Germany
| | - Jim Swoger
- EMBL/CRG Systems Biology Research Unit, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr Aiguader 88, Barcelona 08003, Spain.,Universitat Pompeu Fabra (UPF), 08003 Barcelona, Spain
| | - Steven Djordjevic
- The ithree Institute, The University of Technology Sydney, Sydney, New South Wales 2007, Australia
| | - Lynne Turnbull
- The ithree Institute, The University of Technology Sydney, Sydney, New South Wales 2007, Australia
| | - Cynthia Whitchurch
- The ithree Institute, The University of Technology Sydney, Sydney, New South Wales 2007, Australia
| | - Makoto Miyata
- Department of Biology, Graduate School of Science, Osaka City University, 558-8585 Osaka, Japan.,OCU Advanced Research Institute for Natural Science and Technology (OCARNA), Osaka City University, 558-8585 Osaka, Japan
| | - Marc A Marti-Renom
- Universitat Pompeu Fabra (UPF), 08003 Barcelona, Spain.,Gene Regulation, Stem Cells and Cancer Program. Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr Aiguader 88, Barcelona 08003, Spain.,CNAG-CRG, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Baldiri Reixac 4, Barcelona 08028, Spain.,Institució Catalana de Recerca i Estudis Avançats (ICREA), 08010 Barcelona, Spain
| | - Maria Lluch-Senar
- EMBL/CRG Systems Biology Research Unit, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr Aiguader 88, Barcelona 08003, Spain.,Universitat Pompeu Fabra (UPF), 08003 Barcelona, Spain
| | - Luís Serrano
- EMBL/CRG Systems Biology Research Unit, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr Aiguader 88, Barcelona 08003, Spain.,Universitat Pompeu Fabra (UPF), 08003 Barcelona, Spain.,Institució Catalana de Recerca i Estudis Avançats (ICREA), 08010 Barcelona, Spain
| |
Collapse
|
19
|
Regulation of Gene and Protein Expression in the Lyme Disease Spirochete. Curr Top Microbiol Immunol 2017; 415:83-112. [PMID: 29064060 DOI: 10.1007/82_2017_49] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The infectious cycle of Borrelia burgdorferi necessitates persistent infection of both vertebrates and ticks, and efficient means of transmission between those two very different types of hosts. The Lyme disease spirochete has evolved mechanisms to sense its location in the infectious cycle, and use that information to control production of the proteins and other factors required for each step. Numerous components of borrelial regulatory pathways have been characterized to date. Their effects are being pieced together, thereby providing glimpses into a complex web of cooperative and antagonistic interactions. In this chapter, we present a broad overview of B. burgdorferi gene and protein regulation during the natural infectious cycle, discussions of culture-based methods for elucidating regulatory mechanisms, and summaries of many of the known regulatory proteins and small molecules. We also highlight areas that are in need of substantially more research.
Collapse
|
20
|
Structural basis of the high thermal stability of the histone-like HU protein from the mollicute Spiroplasma melliferum KC3. Sci Rep 2016; 6:36366. [PMID: 27808161 PMCID: PMC5093408 DOI: 10.1038/srep36366] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Accepted: 10/13/2016] [Indexed: 02/07/2023] Open
Abstract
The three-dimensional structure of the histone-like HU protein from the mycoplasma Spiroplasma melliferum KC3 (HUSpm) was determined at 1.4 Å resolution, and the thermal stability of the protein was evaluated by differential scanning calorimetry. A detailed analysis revealed that the three-dimensional structure of the HUSpm dimer is similar to that of its bacterial homologues but is characterized by stronger hydrophobic interactions at the dimer interface. This HUSpm dimer interface lacks salt bridges but is stabilized by a larger number of hydrogen bonds. According to the DSC data, HUSpm has a high denaturation temperature, comparable to that of HU proteins from thermophilic bacteria. To elucidate the structural basis of HUSpm thermal stability, we identified amino acid residues potentially responsible for this property and modified them by site-directed mutagenesis. A comparative analysis of the melting curves of mutant and wild-type HUSpm revealed the motifs that play a key role in protein thermal stability: non-conserved phenylalanine residues in the hydrophobic core, an additional hydrophobic loop at the N-terminal region of the protein, the absence of the internal cavity present at the dimer interface of some HU proteins, and the presence of additional hydrogen bonds between the monomers that are missing in homologous proteins.
Collapse
|
21
|
Hammel M, Amlanjyoti D, Reyes FE, Chen JH, Parpana R, Tang HYH, Larabell CA, Tainer JA, Adhya S. HU multimerization shift controls nucleoid compaction. SCIENCE ADVANCES 2016; 2:e1600650. [PMID: 27482541 PMCID: PMC4966879 DOI: 10.1126/sciadv.1600650] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Accepted: 06/14/2016] [Indexed: 05/05/2023]
Abstract
Molecular mechanisms controlling functional bacterial chromosome (nucleoid) compaction and organization are surprisingly enigmatic but partly depend on conserved, histone-like proteins HUαα and HUαβ and their interactions that span the nanoscale and mesoscale from protein-DNA complexes to the bacterial chromosome and nucleoid structure. We determined the crystal structures of these chromosome-associated proteins in complex with native duplex DNA. Distinct DNA binding modes of HUαα and HUαβ elucidate fundamental features of bacterial chromosome packing that regulate gene transcription. By combining crystal structures with solution x-ray scattering results, we determined architectures of HU-DNA nucleoproteins in solution under near-physiological conditions. These macromolecular conformations and interactions result in contraction at the cellular level based on in vivo imaging of native unlabeled nucleoid by soft x-ray tomography upon HUβ and ectopic HUα38 expression. Structural characterization of charge-altered HUαα-DNA complexes reveals an HU molecular switch that is suitable for condensing nucleoid and reprogramming noninvasive Escherichia coli into an invasive form. Collective findings suggest that shifts between networking and cooperative and noncooperative DNA-dependent HU multimerization control DNA compaction and supercoiling independently of cellular topoisomerase activity. By integrating x-ray crystal structures, x-ray scattering, mutational tests, and x-ray imaging that span from protein-DNA complexes to the bacterial chromosome and nucleoid structure, we show that defined dynamic HU interaction networks can promote nucleoid reorganization and transcriptional regulation as efficient general microbial mechanisms to help synchronize genetic responses to cell cycle, changing environments, and pathogenesis.
Collapse
Affiliation(s)
- Michal Hammel
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Corresponding author. (M.H.); (J.A.T.)
| | - Dhar Amlanjyoti
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Francis E. Reyes
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Jian-Hua Chen
- Department of Anatomy, University of California San Francisco, San Francisco, CA 94143, USA
| | - Rochelle Parpana
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Henry Y. H. Tang
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Carolyn A. Larabell
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Department of Anatomy, University of California San Francisco, San Francisco, CA 94143, USA
| | - John A. Tainer
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA
- Corresponding author. (M.H.); (J.A.T.)
| | - Sankar Adhya
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| |
Collapse
|
22
|
HU histone-like DNA-binding protein from Thermus thermophilus: structural and evolutionary analyses. Extremophiles 2016; 20:695-709. [DOI: 10.1007/s00792-016-0859-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 06/14/2016] [Indexed: 10/21/2022]
|
23
|
Distinct structural features of TFAM drive mitochondrial DNA packaging versus transcriptional activation. Nat Commun 2015; 5:3077. [PMID: 24435062 PMCID: PMC3936014 DOI: 10.1038/ncomms4077] [Citation(s) in RCA: 163] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Accepted: 12/06/2013] [Indexed: 12/19/2022] Open
Abstract
TFAM (transcription factor A, mitochondrial) is a DNA-binding protein that activates transcription at the two major promoters of mitochondrial DNA (mtDNA)--the light strand promoter (LSP) and the heavy strand promoter 1 (HSP1). Equally important, it coats and packages the mitochondrial genome. TFAM has been shown to impose a U-turn on LSP DNA; however, whether this distortion is relevant at other sites is unknown. Here we present crystal structures of TFAM bound to HSP1 and to nonspecific DNA. In both, TFAM similarly distorts the DNA into a U-turn. Yet, TFAM binds to HSP1 in the opposite orientation from LSP explaining why transcription from LSP requires DNA bending, whereas transcription at HSP1 does not. Moreover, the crystal structures reveal dimerization of DNA-bound TFAM. This dimerization is dispensable for DNA bending and transcriptional activation but is important in DNA compaction. We propose that TFAM dimerization enhances mitochondrial DNA compaction by promoting looping of the DNA.
Collapse
|
24
|
Coleman JL, Toledo A, Benach JL. Borrelia burgdorferi HtrA: evidence for twofold proteolysis of outer membrane protein p66. Mol Microbiol 2015; 99:135-50. [PMID: 26370492 DOI: 10.1111/mmi.13221] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/11/2015] [Indexed: 12/20/2022]
Abstract
In prokaryotes, members of the High Temperature Requirement A (HtrA) family of serine proteases function in the periplasm to degrade damaged or improperly folded membrane proteins. Borrelia burgdorferi, the agent of Lyme disease, codes for a single HtrA homolog. Two-dimensional electrophoresis analysis of B. burgdorferi B31A3 and a strain that overexpresses HtrA (A3HtrAOE) identified a downregulated protein in A3HtrAOE with a mass, pI and MALDI-TOF spectrum consistent with outer membrane protein p66. P66 and HtrA from cellular lysates partitioned into detergent-resistant membranes, which contain cholesterol-glycolipid-rich membrane regions known as lipid rafts, suggesting that HtrA and p66 may reside together in lipid rafts also. This agrees with previous work from our laboratory, which showed that HtrA and p66 are constituents of B. burgdorferi outer membrane vesicles. HtrA degraded p66 in vitro and A3HtrAOE expressed reduced levels of p66 in vivo. Fluorescence confocal microscopy revealed that HtrA and p66 colocalize in the membrane. The association of HtrA and p66 establishes that they could interact efficiently and their protease/substrate relationship provides functional relevance to this interaction. A3HtrAOE also showed reduced levels of p66 transcript in comparison with wild-type B31A3, indicating that HtrA-mediated regulation of p66 may occur at multiple levels.
Collapse
Affiliation(s)
- James L Coleman
- New York State Department of Health, Stony Brook University, Stony Brook, NY, USA.,Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, NY, USA
| | - Alvaro Toledo
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, NY, USA
| | - Jorge L Benach
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, NY, USA
| |
Collapse
|
25
|
The nucleoid-associated protein HU enhances 8-oxoguanine base excision by the formamidopyrimidine-DNA glycosylase. Biochem J 2015; 471:13-23. [DOI: 10.1042/bj20150387] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 07/10/2015] [Indexed: 11/17/2022]
Abstract
The major E. coli histone-like HU protein is identified as a strong stimulator of the DNA glycosylase Fpg by inducing enzyme product release. According to an active molecular process, HU acts as a molecular partner for an efficient DNA-repair process.
Collapse
|
26
|
Shevtsov MB, Streeter SD, Thresh SJ, Swiderska A, McGeehan JE, Kneale GG. Structural analysis of DNA binding by C.Csp231I, a member of a novel class of R-M controller proteins regulating gene expression. ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2015; 71:398-407. [PMID: 25664751 PMCID: PMC4321490 DOI: 10.1107/s139900471402690x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Accepted: 12/08/2014] [Indexed: 01/03/2023]
Abstract
In a wide variety of bacterial restriction-modification systems, a regulatory `controller' protein (or C-protein) is required for effective transcription of its own gene and for transcription of the endonuclease gene found on the same operon. We have recently turned our attention to a new class of controller proteins (exemplified by C.Csp231I) that have quite novel features, including a much larger DNA-binding site with an 18 bp (∼60 Å) spacer between the two palindromic DNA-binding sequences and a very different recognition sequence from the canonical GACT/AGTC. Using X-ray crystallography, the structure of the protein in complex with its 21 bp DNA-recognition sequence was solved to 1.8 Å resolution, and the molecular basis of sequence recognition in this class of proteins was elucidated. An unusual aspect of the promoter sequence is the extended spacer between the dimer binding sites, suggesting a novel interaction between the two C-protein dimers when bound to both recognition sites correctly spaced on the DNA. A U-bend model is proposed for this tetrameric complex, based on the results of gel-mobility assays, hydrodynamic analysis and the observation of key contacts at the interface between dimers in the crystal.
Collapse
Affiliation(s)
- M. B. Shevtsov
- Biophysics Laboratories, Institute of Biomedical and Biomolecular Sciences, School of Biological Sciences, University of Portsmouth, Portsmouth PO1 2DY, England
| | - S. D. Streeter
- Biophysics Laboratories, Institute of Biomedical and Biomolecular Sciences, School of Biological Sciences, University of Portsmouth, Portsmouth PO1 2DY, England
| | - S.-J. Thresh
- Biophysics Laboratories, Institute of Biomedical and Biomolecular Sciences, School of Biological Sciences, University of Portsmouth, Portsmouth PO1 2DY, England
| | - A. Swiderska
- Biophysics Laboratories, Institute of Biomedical and Biomolecular Sciences, School of Biological Sciences, University of Portsmouth, Portsmouth PO1 2DY, England
| | - J. E. McGeehan
- Biophysics Laboratories, Institute of Biomedical and Biomolecular Sciences, School of Biological Sciences, University of Portsmouth, Portsmouth PO1 2DY, England
| | - G. G. Kneale
- Biophysics Laboratories, Institute of Biomedical and Biomolecular Sciences, School of Biological Sciences, University of Portsmouth, Portsmouth PO1 2DY, England
| |
Collapse
|
27
|
Kim DH, Im H, Jee JG, Jang SB, Yoon HJ, Kwon AR, Kang SM, Lee BJ. β-Arm flexibility of HU fromStaphylococcus aureusdictates the DNA-binding and recognition mechanism. ACTA ACUST UNITED AC 2014; 70:3273-89. [DOI: 10.1107/s1399004714023931] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Accepted: 10/30/2014] [Indexed: 12/11/2022]
Abstract
HU, one of the major nucleoid-associated proteins, interacts with the minor groove of DNA in a nonspecific manner to induce DNA bending or to stabilize bent DNA. In this study, crystal structures are reported for both free HU fromStaphylococcus aureusMu50 (SHU) and SHU bound to 21-mer dsDNA. The structures, in combination with electrophoretic mobility shift assays (EMSAs), isothermal titration calorimetry (ITC) measurements and molecular-dynamics (MD) simulations, elucidate the overall and residue-specific changes in SHU upon recognizing and binding to DNA. Firstly, structural comparison showed the flexible nature of the β-sheets of the DNA-binding domain and that the β-arms bend inwards upon complex formation, whereas the other portions are nearly unaltered. Secondly, it was found that the disruption and formation of salt bridges accompanies DNA binding. Thirdly, residue-specific free-energy analyses using the MM-PBSA method with MD simulation data suggested that the successive basic residues in the β-arms play a central role in recognizing and binding to DNA, which was confirmed by the EMSA and ITC analyses. Moreover, residue Arg55 resides in the hinge region of the flexible β-arms, exhibiting a remarkable role in their flexible nature. Fourthly, EMSAs with various DNAs revealed that SHU prefers deformable DNA. Taken together, these data suggest residue-specific roles in local shape and base readouts, which are primarily mediated by the flexible β-arms consisting of residues 50–80.
Collapse
|
28
|
DNA topology confers sequence specificity to nonspecific architectural proteins. Proc Natl Acad Sci U S A 2014; 111:16742-7. [PMID: 25385626 DOI: 10.1073/pnas.1405016111] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Topological constraints placed on short fragments of DNA change the disorder found in chain molecules randomly decorated by nonspecific, architectural proteins into tightly organized 3D structures. The bacterial heat-unstable (HU) protein builds up, counter to expectations, in greater quantities and at particular sites along simulated DNA minicircles and loops. Moreover, the placement of HU along loops with the "wild-type" spacing found in the Escherichia coli lactose (lac) and galactose (gal) operons precludes access to key recognition elements on DNA. The HU protein introduces a unique spatial pathway in the DNA upon closure. The many ways in which the protein induces nearly the same closed circular configuration point to the statistical advantage of its nonspecificity. The rotational settings imposed on DNA by the repressor proteins, by contrast, introduce sequential specificity in HU placement, with the nonspecific protein accumulating at particular loci on the constrained duplex. Thus, an architectural protein with no discernible DNA sequence-recognizing features becomes site-specific and potentially assumes a functional role upon loop formation. The locations of HU on the closed DNA reflect long-range mechanical correlations. The protein responds to DNA shape and deformability—the stiff, naturally straight double-helical structure—rather than to the unique features of the constituent base pairs. The structures of the simulated loops suggest that HU architecture, like nucleosomal architecture, which modulates the ability of regulatory proteins to recognize their binding sites in the context of chromatin, may influence repressor-operator interactions in the context of the bacterial nucleoid.
Collapse
|
29
|
Bhowmick T, Ghosh S, Dixit K, Ganesan V, Ramagopal UA, Dey D, Sarma SP, Ramakumar S, Nagaraja V. Targeting Mycobacterium tuberculosis nucleoid-associated protein HU with structure-based inhibitors. Nat Commun 2014; 5:4124. [PMID: 24916461 DOI: 10.1038/ncomms5124] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Accepted: 05/15/2014] [Indexed: 01/03/2023] Open
Abstract
The nucleoid-associated protein HU plays an important role in maintenance of chromosomal architecture and in global regulation of DNA transactions in bacteria. Although HU is essential for growth in Mycobacterium tuberculosis (Mtb), there have been no reported attempts to perturb HU function with small molecules. Here we report the crystal structure of the N-terminal domain of HU from Mtb. We identify a core region within the HU-DNA interface that can be targeted using stilbene derivatives. These small molecules specifically inhibit HU-DNA binding, disrupt nucleoid architecture and reduce Mtb growth. The stilbene inhibitors induce gene expression changes in Mtb that resemble those induced by HU deficiency. Our results indicate that HU is a potential target for the development of therapies against tuberculosis.
Collapse
Affiliation(s)
- Tuhin Bhowmick
- 1] Department of Physics, Indian Institute of Science, Bangalore 560012, India [2]
| | - Soumitra Ghosh
- 1] Department of Microbiology and Cell biology, Indian Institute of Science, Bangalore 560012, India [2]
| | - Karuna Dixit
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India
| | - Varsha Ganesan
- Department of Microbiology and Cell biology, Indian Institute of Science, Bangalore 560012, India
| | - Udupi A Ramagopal
- 1] Albert Einstein College of Medicine, Jack and Pearl Resnick Campus, 1300 Morris Park Avenue, Ullmann Building, Room 409, Bronx, New York 10461, USA [2] Biological Sciences Division, Poornaprajna Institute of Scientific Research, Bangalore 562110, India
| | - Debayan Dey
- Department of Physics, Indian Institute of Science, Bangalore 560012, India
| | - Siddhartha P Sarma
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India
| | | | - Valakunja Nagaraja
- 1] Department of Microbiology and Cell biology, Indian Institute of Science, Bangalore 560012, India [2] Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
| |
Collapse
|
30
|
Paquet F, Delalande O, Goffinont S, Culard F, Loth K, Asseline U, Castaing B, Landon C. Model of a DNA-protein complex of the architectural monomeric protein MC1 from Euryarchaea. PLoS One 2014; 9:e88809. [PMID: 24558431 PMCID: PMC3928310 DOI: 10.1371/journal.pone.0088809] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Accepted: 01/11/2014] [Indexed: 11/19/2022] Open
Abstract
In Archaea the two major modes of DNA packaging are wrapping by histone proteins or bending by architectural non-histone proteins. To supplement our knowledge about the binding mode of the different DNA-bending proteins observed across the three domains of life, we present here the first model of a complex in which the monomeric Methanogen Chromosomal protein 1 (MC1) from Euryarchaea binds to the concave side of a strongly bent DNA. In laboratory growth conditions MC1 is the most abundant architectural protein present in Methanosarcina thermophila CHTI55. Like most proteins that strongly bend DNA, MC1 is known to bind in the minor groove. Interaction areas for MC1 and DNA were mapped by Nuclear Magnetic Resonance (NMR) data. The polarity of protein binding was determined using paramagnetic probes attached to the DNA. The first structural model of the DNA-MC1 complex we propose here was obtained by two complementary docking approaches and is in good agreement with the experimental data previously provided by electron microscopy and biochemistry. Residues essential to DNA-binding and -bending were highlighted and confirmed by site-directed mutagenesis. It was found that the Arg25 side-chain was essential to neutralize the negative charge of two phosphates that come very close in response to a dramatic curvature of the DNA.
Collapse
Affiliation(s)
- Françoise Paquet
- Centre de Biophysique Moléculaire, Centre National de la Recherche Scientifique UPR 4301, Université d'Orléans, Orleans, France
- * E-mail:
| | - Olivier Delalande
- Faculté des Sciences Pharmaceutiques et Biologiques, Institut de Génétique et Développement de Rennes, Centre National de la Recherche Scientifique UMR 6290, Université de Rennes1, Rennes, France
| | - Stephane Goffinont
- Centre de Biophysique Moléculaire, Centre National de la Recherche Scientifique UPR 4301, Université d'Orléans, Orleans, France
| | - Françoise Culard
- Centre de Biophysique Moléculaire, Centre National de la Recherche Scientifique UPR 4301, Université d'Orléans, Orleans, France
| | - Karine Loth
- Centre de Biophysique Moléculaire, Centre National de la Recherche Scientifique UPR 4301, Université d'Orléans, Orleans, France
| | - Ulysse Asseline
- Centre de Biophysique Moléculaire, Centre National de la Recherche Scientifique UPR 4301, Université d'Orléans, Orleans, France
| | - Bertrand Castaing
- Centre de Biophysique Moléculaire, Centre National de la Recherche Scientifique UPR 4301, Université d'Orléans, Orleans, France
| | - Celine Landon
- Centre de Biophysique Moléculaire, Centre National de la Recherche Scientifique UPR 4301, Université d'Orléans, Orleans, France
| |
Collapse
|
31
|
Kukat C, Larsson NG. mtDNA makes a U-turn for the mitochondrial nucleoid. Trends Cell Biol 2013; 23:457-63. [PMID: 23721879 DOI: 10.1016/j.tcb.2013.04.009] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Revised: 04/17/2013] [Accepted: 04/22/2013] [Indexed: 11/29/2022]
Abstract
Mitochondria contain mtDNA derived from the ancestral endosymbiont genome. Important subunits of the oxidative phosphorylation system, which supplies cells with the energy currency ATP, are encoded by mtDNA. A naked mtDNA molecule is longer than a typical mitochondrion and is therefore compacted in vivo to form a nucleoprotein complex, denoted the mitochondrial nucleoid. Mitochondrial transcription factor A (TFAM) is the main factor packaging mtDNA into nucleoids and is also essential for mtDNA transcription initiation. The crystal structure of TFAM shows that it bends mtDNA in a sharp U-turn, which likely provides the structural basis for its dual functions. Super-resolution imaging studies have revealed that the nucleoid has an average diameter of ∼100nm and frequently contains a single copy of mtDNA. In this review the structure of the mitochondrial nucleoid and its possible regulatory roles in mtDNA expression will be discussed.
Collapse
Affiliation(s)
- Christian Kukat
- Department of Mitochondrial Biology, Max Planck Institute for Biology of Ageing, Joseph-Stelzmann-Strasse 9b, 50931 Cologne, Germany
| | | |
Collapse
|
32
|
Abstract
The 3DNA software package is a popular and versatile bioinformatics tool with capabilities to analyze, construct, and visualize three-dimensional nucleic acid structures. This article presents detailed protocols for a subset of new and popular features available in 3DNA, applicable to both individual structures and ensembles of related structures. Protocol 1 lists the set of instructions needed to download and install the software. This is followed, in Protocol 2, by the analysis of a nucleic acid structure, including the assignment of base pairs and the determination of rigid-body parameters that describe the structure and, in Protocol 3, by a description of the reconstruction of an atomic model of a structure from its rigid-body parameters. The most recent version of 3DNA, version 2.1, has new features for the analysis and manipulation of ensembles of structures, such as those deduced from nuclear magnetic resonance (NMR) measurements and molecular dynamic (MD) simulations; these features are presented in Protocols 4 and 5. In addition to the 3DNA stand-alone software package, the w3DNA web server, located at http://w3dna.rutgers.edu, provides a user-friendly interface to selected features of the software. Protocol 6 demonstrates a novel feature of the site for building models of long DNA molecules decorated with bound proteins at user-specified locations.
Collapse
Affiliation(s)
- Andrew V Colasanti
- Department of Chemistry & Chemical Biology and BioMaPS Institute for Quantitative Biology, Rutgers - The State University of New Jersey.
| | | | | |
Collapse
|
33
|
New insights into DNA-binding by type IIA topoisomerases. Curr Opin Struct Biol 2013; 23:125-33. [DOI: 10.1016/j.sbi.2012.11.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Revised: 11/28/2012] [Accepted: 11/29/2012] [Indexed: 11/18/2022]
|
34
|
Wolfe KC, Hastings WA, Dutta S, Long A, Shapiro BA, Woolf TB, Guthold M, Chirikjian GS. Multiscale modeling of double-helical DNA and RNA: a unification through Lie groups. J Phys Chem B 2012; 116:8556-72. [PMID: 22676719 PMCID: PMC4833121 DOI: 10.1021/jp2126015] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Several different mechanical models of double-helical nucleic-acid structures that have been presented in the literature are reviewed here together with a new analysis method that provides a reconciliation between these disparate models. In all cases, terminology and basic results from the theory of Lie groups are used to describe rigid-body motions in a coordinate-free way, and when necessary, coordinates are introduced in a way in which simple equations result. We consider double-helical DNAs and RNAs which, in their unstressed referential state, have backbones that are either straight, slightly precurved, or bent by the action of a protein or other bound molecule. At the coarsest level, we consider worm-like chains with anisotropic bending stiffness. Then, we show how bi-rod models converge to this for sufficiently long filament lengths. At a finer level, we examine elastic networks of rigid bases and show how these relate to the coarser models. Finally, we show how results from molecular dynamics simulation at full atomic resolution (which is the finest scale considered here) and AFM experimental measurements (which is at the coarsest scale) relate to these models.
Collapse
Affiliation(s)
- Kevin C. Wolfe
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, Maryland, United States
| | | | - Samrat Dutta
- Department of Physics, Wake Forest University, Winston-Salem, North Carolina, United States
| | - Andrew Long
- Department of Mechanical Engineering, Northwestern University, Evanston, Illinois, United States
| | - Bruce A. Shapiro
- Center for Cancer Research Nanobiology Program, Frederick National Laboratory for Cancer Research, National Cancer Institute, Frederick, Maryland, United States
| | - Thomas B. Woolf
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Martin Guthold
- Department of Physics, Wake Forest University, Winston-Salem, North Carolina, United States
| | - Gregory S. Chirikjian
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, Maryland, United States
| |
Collapse
|
35
|
Mapping the Transition State for DNA Bending by IHF. J Mol Biol 2012; 418:300-15. [DOI: 10.1016/j.jmb.2012.02.028] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Revised: 02/14/2012] [Accepted: 02/17/2012] [Indexed: 01/01/2023]
|
36
|
EbfC (YbaB) is a new type of bacterial nucleoid-associated protein and a global regulator of gene expression in the Lyme disease spirochete. J Bacteriol 2012; 194:3395-406. [PMID: 22544270 DOI: 10.1128/jb.00252-12] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Nearly every known species of Eubacteria encodes a homolog of the Borrelia burgdorferi EbfC DNA-binding protein. We now demonstrate that fluorescently tagged EbfC associates with B. burgdorferi nucleoids in vivo and that chromatin immunoprecipitation (ChIP) of wild-type EbfC showed it to bind in vivo to sites throughout the genome, two hallmarks of nucleoid-associated proteins. Comparative RNA sequencing (RNA-Seq) of a mutant B. burgdorferi strain that overexpresses EbfC indicated that approximately 4.5% of borrelial genes are significantly impacted by EbfC. The ebfC gene was highly expressed in rapidly growing bacteria, but ebfC mRNA was undetectable in stationary phase. Combined with previous data showing that EbfC induces bends in DNA, these results demonstrate that EbfC is a nucleoid-associated protein and lead to the hypothesis that B. burgdorferi utilizes cellular fluctuations in EbfC levels to globally control transcription of numerous genes. The ubiquity of EbfC proteins in Eubacteria suggests that these results apply to a wide range of pathogens and other bacteria.
Collapse
|
37
|
Clauvelin N, Olson WK, Tobias I. Characterization of the geometry and topology of DNA pictured as a discrete collection of atoms. J Chem Theory Comput 2012; 8:1092-1107. [PMID: 24791158 DOI: 10.1021/ct200657e] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The structural and physical properties of DNA are closely related to its geometry and topology. The classical mathematical treatment of DNA geometry and topology in terms of ideal smooth space curves was not designed to characterize the spatial arrangements of atoms found in high-resolution and simulated double-helical structures. We present here new and rigorous numerical methods for the rapid and accurate assessment of the geometry and topology of double-helical DNA structures in terms of the constituent atoms. These methods are well designed for large DNA datasets obtained in detailed numerical simulations or determined experimentally at high-resolution. We illustrate the usefulness of our methodology by applying it to the analysis of three canonical double-helical DNA chains, a 65-bp minicircle obtained in recent molecular dynamics simulations, and a crystallographic array of protein-bound DNA duplexes. Although we focus on fully base-paired DNA structures, our methods can be extended to treat the geometry and topology of melted DNA structures as well as to characterize the folding of arbitrary molecules such as RNA and cyclic peptides.
Collapse
Affiliation(s)
- Nicolas Clauvelin
- BioMaPS Institute for Quantitative Biology, Rutgers, the State University of New Jersey, Piscataway, New Jersey, 08854, USA, and Department of Chemistry and Chemical Biology, Rutgers, the State University of New Jersey, Piscataway, New Jersey, 08854, USA
| | - Wilma K Olson
- BioMaPS Institute for Quantitative Biology, Rutgers, the State University of New Jersey, Piscataway, New Jersey, 08854, USA, and Department of Chemistry and Chemical Biology, Rutgers, the State University of New Jersey, Piscataway, New Jersey, 08854, USA
| | - Irwin Tobias
- BioMaPS Institute for Quantitative Biology, Rutgers, the State University of New Jersey, Piscataway, New Jersey, 08854, USA, and Department of Chemistry and Chemical Biology, Rutgers, the State University of New Jersey, Piscataway, New Jersey, 08854, USA
| |
Collapse
|
38
|
Abstract
Borrelia burgdorferi, the spirochete that causes Lyme disease, is maintained in nature via an enzootic cycle that comprises a tick vector and a vertebrate host. Transmission from the tick to the mammal, acquisition from the mammal back to the tick, and adaptation to the two disparate environments require sensing signals and responding by regulating programs of gene expression. The molecular mechanisms utilized to effect these lifestyle changes have begun to be elucidated and feature an alternative sigma factor cascade in which RpoN (σ(54)) and RpoS (σ(S)) globally control the genes required for the different phases of the enzootic cycle. The RpoN-RpoS pathway is surprisingly complex, entailing Rrp2, an unusual enhancer-binding protein and two-component regulatory system response regulator activated by acetyl phosphate; BosR, an unorthodox DNA-binding protein; DsrA(Bb), a small noncoding RNA; and Hfq and CsrA, two RNA-binding proteins. B. burgdorferi also has a c-di-GMP signaling system that regulates the tick side of the enzootic cycle and whose function is only beginning to be appreciated.
Collapse
Affiliation(s)
- D Scott Samuels
- Division of Biological Sciences and Biochemistry Program, The University of Montana, Missoula, Montana 59812, USA.
| |
Collapse
|
39
|
|
40
|
Ngo HB, Kaiser JT, Chan DC. The mitochondrial transcription and packaging factor Tfam imposes a U-turn on mitochondrial DNA. Nat Struct Mol Biol 2011; 18:1290-6. [PMID: 22037171 PMCID: PMC3210390 DOI: 10.1038/nsmb.2159] [Citation(s) in RCA: 194] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2011] [Accepted: 09/13/2011] [Indexed: 11/11/2022]
Abstract
Tfam, a DNA binding protein with tandem HMG (high mobility group)-box domains, plays a central role in expression, maintenance, and organization of the mitochondrial genome. It activates transcription from mitochondrial promoters and organizes the mitochondrial genome into nucleoids. Using X-ray crystallography, we show that human Tfam forces promoter DNA to undergo a U-turn, reversing the direction of the DNA helix. Each HMG-box domain wedges into the DNA minor groove to generate two kinks on one face of the DNA. On the opposite face, a positively charged α-helix serves as a platform to facilitate DNA bending. The structural principles underlying DNA bending converge with those of the unrelated HU family proteins, which play analogous architectural roles in organizing bacterial nucleoids. The functional importance of this extreme DNA bending is promoter-specific and appears related to the orientation of Tfam on the promoters.
Collapse
Affiliation(s)
- Huu B Ngo
- Division of Biology, California Institute of Technology, Pasadena, California, USA
| | | | | |
Collapse
|
41
|
Collier C, Machón C, Briggs GS, Smits WK, Soultanas P. Untwisting of the DNA helix stimulates the endonuclease activity of Bacillus subtilis Nth at AP sites. Nucleic Acids Res 2011; 40:739-50. [PMID: 21954439 PMCID: PMC3258159 DOI: 10.1093/nar/gkr785] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Bacterial nucleoid associated proteins play a variety of roles in genome maintenance and dynamics. Their involvement in genome packaging, DNA replication and transcription are well documented but it is still unclear whether they play any specific roles in genome repair. We discovered that untwisting of the DNA double helix by bacterial non-specific DNA binding proteins stimulates the activity of a repair endonuclease of the Nth/MutY family involved in abasic site removal during base excision repair. The essential Bacillus subtilis primosomal gene dnaD, coding for a protein with DNA-untwisting activity, is in the same operon with nth and the promoter activity of this operon is transiently stimulated by H(2)O(2). Consequently, dnaD mRNA levels persist high upon treatment with H(2)O(2) compared to the reduced mRNA levels of the other essential primosomal genes dnaB and dnaI, suggesting that DnaD may play an important role in DNA repair in addition to its essential role in replication initiation. Homologous Nth repair endonucleases are found in nearly all organisms, including humans. Our data have wider implications for DNA repair as they suggest that genome associated proteins that alter the superhelicity of the DNA indirectly facilitate base excision repair mediated by repair endonucleases of the Nth/MutY family.
Collapse
Affiliation(s)
- Christopher Collier
- Centre for Biomolecular Sciences, School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | | | | | | | | |
Collapse
|
42
|
Kamashev D, Oberto J, Serebryakova M, Gorbachev A, Zhukova Y, Levitskii S, Mazur AK, Govorun V. Mycoplasma gallisepticum Produces a Histone-like Protein That Recognizes Base Mismatches in DNA. Biochemistry 2011; 50:8692-702. [DOI: 10.1021/bi2009097] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Dmitri Kamashev
- Research Institute for Physico-Chemical Medicine, Moscow
119435, Russia
- National Research Centre Kurchatov Institute, Moscow, 123182, Russia
| | - Jacques Oberto
- Institut
de Génétique et Microbiologie, CNRS UMR 8621, Université Paris XI, Paris, France
| | | | - Alexey Gorbachev
- Research Institute for Physico-Chemical Medicine, Moscow
119435, Russia
| | - Yulia Zhukova
- Research Institute for Physico-Chemical Medicine, Moscow
119435, Russia
| | - Sergei Levitskii
- Research Institute for Physico-Chemical Medicine, Moscow
119435, Russia
- National Research Centre Kurchatov Institute, Moscow, 123182, Russia
| | - Alexey K. Mazur
- UPR9080 CNRS, Université Paris Diderot, Sorbonne Paris Cité, Institut
de Biologie Physico-Chimique, 13, rue Pierre et Marie Curie, Paris
75005, France
| | - Vadim Govorun
- Research Institute for Physico-Chemical Medicine, Moscow
119435, Russia
- National Research Centre Kurchatov Institute, Moscow, 123182, Russia
| |
Collapse
|
43
|
Quantification of mRNA and protein and integration with protein turnover in a bacterium. Mol Syst Biol 2011; 7:511. [PMID: 21772259 PMCID: PMC3159969 DOI: 10.1038/msb.2011.38] [Citation(s) in RCA: 218] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2011] [Accepted: 05/20/2011] [Indexed: 12/12/2022] Open
Abstract
Determination of the average cellular copy number of 400 proteins under different growth conditions and integration with protein turnover and absolute mRNA levels reveals the dynamics of protein expression in the genome-reduced bacterium Mycoplasma pneumoniae. Our study provides a fine-grained, quantitative picture to unprecedented detail in an established model organism for systems-wide studies. Our integrative approach reveals a novel, dynamic view on the processes, interactions and regulations underlying the central dogma pathway and the composition of protein complexes. Simulations using our quantitative data on mRNA, protein and turnover show how an organism copes with stochastic noise in gene expression in vivo. Our data serve as an important resource for colleagues both within our field of research and in related disciplines.
A hallmark of Systems Biology is the integration of diverse, large quantitative data sets with the aim to gain novel insights into how biological processes work. We measured individual mRNA and protein abundances as well as protein turnover in the bacterium Mycoplasma pneumoniae. This human pathogen is an ideal model organism for organism-wide studies. It can be readily cultured under laboratory conditions and it has a very small genome with only 690 protein-coding genes. This comparably low complexity allows for the exhaustive analysis of major cellular biomolecules avoiding constrains introduced by limitations of available analysis techniques. Using a recently developed mass spectrometry-based approach, we determined the average cellular copy number for over 400 individual proteins under different growth and stress conditions. The 20 most abundant proteins, including Elongation factor Tu, cellular chaperones, and proteins involved in metabolizing glucose, the major energy source of M. pneumoniae account for nearly 44% of the total cellular protein mass. We observed abundance changes of many expected and several unexpected proteins in response to cellular stress, such as heat shock, DNA damage and osmotic stress, as well as along batch culture growth over 4 days. Integration of the protein abundance data with quantitative mRNA measurements revealed a modest correlation between these two classes of biomolecules. However, for several classical stress-induced proteins, we observed a correlated induction of mRNA and protein in response to heat shock. A focused analysis of mRNA–protein abundance dynamics during batch culture growth suggested that the regulation of gene expression is largely decoupled from protein dynamics in M. pneumoniae, indicating extensive post-transcriptional and post-translational regulation influencing the cellular mRNA–protein ratios. To investigate the factors influencing the cellular protein abundance, we measured individual protein turnover rates by mass spectrometry using a label-chase approach involving stable isotope-labelled amino acids. The average half-life of a protein in M. pneumoniae is 23 h. Based on the measured quantitative mRNA data, the protein abundances and their half-lives, we established an ordinary differential equations model for the estimation of individual in vivo protein degradation and translation efficiency rates. We found out that translation efficiency rather than protein turnover is the dominating factor influencing protein abundance. Using our abundance and turnover data, we additionally performed stochastic simulations of gene expression. We observed that long protein half-life and low translational efficiency buffers gene expression noise propagating from low cellular mRNA levels in vivo. We compared the abundance ratios of proteins associating into complexes in vivo with their expected functional stoichiometries. We observed that for stable protein complexes, such as the GroEL/ES chaperonin or DNA gyrase, our measured abundance ratios reflected the expected subunit stoichiometries. More dynamic protein complexes, such as the DnaK/J/GrpE chaperone system or RNA polymerase, showed several unusual subunit ratios, pointing towards transient interaction of sub-stoichiometric subunits for function. A detailed, quantitative analysis of the ribosome, the largest cellular protein complex, revealed large abundance differences of the 51 subunits. This observation indicates a multi-functionality for several, abundant ribosomal proteins. Finally, a comparison of the determined average cellular protein abundances with a different pathogenic bacterium, Leptospira interrogans, revealed that cellular protein abundances closely reflect their respective lifestyles. Our study represents an organism-wide, quantitative analysis of cellular protein abundances. Integrating our proteomics data with determined mRNA levels and protein turnover rates reveals insights into the dynamic interplay and regulation of mRNA and proteins, the central biomolecules of a cell. Biological function and cellular responses to environmental perturbations are regulated by a complex interplay of DNA, RNA, proteins and metabolites inside cells. To understand these central processes in living systems at the molecular level, we integrated experimentally determined abundance data for mRNA, proteins, as well as individual protein half-lives from the genome-reduced bacterium Mycoplasma pneumoniae. We provide a fine-grained, quantitative analysis of basic intracellular processes under various external conditions. Proteome composition changes in response to cellular perturbations reveal specific stress response strategies. The regulation of gene expression is largely decoupled from protein dynamics and translation efficiency has a higher regulatory impact on protein abundance than protein turnover. Stochastic simulations using in vivo data show how low translation efficiency and long protein half-lives effectively reduce biological noise in gene expression. Protein abundances are regulated in functional units, such as complexes or pathways, and reflect cellular lifestyles. Our study provides a detailed integrative analysis of average cellular protein abundances and the dynamic interplay of mRNA and proteins, the central biomolecules of a cell.
Collapse
|
44
|
Levitskiy S, Sycheva A, Kharlampieva D, Oberto J, Kamashev D, Serebryakova M, Moshkovskii S, Lazarev V, Govorun V. Purification and functional analysis of recombinant Acholeplasma laidlawii histone-like HU protein. Biochimie 2011; 93:1102-9. [DOI: 10.1016/j.biochi.2011.03.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2010] [Accepted: 03/09/2011] [Indexed: 01/04/2023]
|
45
|
Firczuk M, Wojciechowski M, Czapinska H, Bochtler M. DNA intercalation without flipping in the specific ThaI-DNA complex. Nucleic Acids Res 2010; 39:744-54. [PMID: 20861000 PMCID: PMC3025569 DOI: 10.1093/nar/gkq834] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The PD-(D/E)XK type II restriction endonuclease ThaI cuts the target sequence CG/CG with blunt ends. Here, we report the 1.3 Å resolution structure of the enzyme in complex with substrate DNA and a sodium or calcium ion taking the place of a catalytic magnesium ion. The structure identifies Glu54, Asp82 and Lys93 as the active site residues. This agrees with earlier bioinformatic predictions and implies that the PD and (D/E)XK motifs in the sequence are incidental. DNA recognition is very unusual: the two Met47 residues of the ThaI dimer intercalate symmetrically into the CG steps of the target sequence. They approach the DNA from the minor groove side and penetrate the base stack entirely. The DNA accommodates the intercalating residues without nucleotide flipping by a doubling of the CG step rise to twice its usual value, which is accompanied by drastic unwinding. Displacement of the Met47 side chains from the base pair midlines toward the downstream CG steps leads to large and compensating tilts of the first and second CG steps. DNA intercalation by ThaI is unlike intercalation by HincII, HinP1I or proteins that bend or repair DNA.
Collapse
|
46
|
Dresser AR, Hardy PO, Chaconas G. Investigation of the genes involved in antigenic switching at the vlsE locus in Borrelia burgdorferi: an essential role for the RuvAB branch migrase. PLoS Pathog 2009; 5:e1000680. [PMID: 19997508 PMCID: PMC2779866 DOI: 10.1371/journal.ppat.1000680] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2009] [Accepted: 11/04/2009] [Indexed: 12/23/2022] Open
Abstract
Persistent infection by pathogenic organisms requires effective strategies for the defense of these organisms against the host immune response. A common strategy employed by many pathogens to escape immune recognition and clearance is to continually vary surface epitopes through recombinational shuffling of genetic information. Borrelia burgdorferi, a causative agent of Lyme borreliosis, encodes a surface-bound lipoprotein, VlsE. This protein is encoded by the vlsE locus carried at the right end of the linear plasmid lp28-1. Adjacent to the expression locus are 15 silent cassettes carrying information that is moved into the vlsE locus through segmental gene conversion events. The protein players and molecular mechanism of recombinational switching at vlsE have not been characterized. In this study, we analyzed the effect of the independent disruption of 17 genes that encode factors involved in DNA recombination, repair or replication on recombinational switching at the vlsE locus during murine infection. In Neisseria gonorrhoeae, 10 such genes have been implicated in recombinational switching at the pilE locus. Eight of these genes, including recA, are either absent from B. burgdorferi, or do not show an obvious requirement for switching at vlsE. The only genes that are required in both organisms are ruvA and ruvB, which encode subunits of a Holliday junction branch migrase. Disruption of these genes results in a dramatic decrease in vlsE recombination with a phenotype similar to that observed for lp28-1 or vls-minus spirochetes: productive infection at week 1 with clearance by day 21. In SCID mice, the persistence defect observed with ruvA and ruvB mutants was fully rescued as previously observed for vlsE-deficient B. burgdorferi. We report the requirement of the RuvAB branch migrase in recombinational switching at vlsE, the first essential factor to be identified in this process. These findings are supported by the independent work of Lin et al. in the accompanying article, who also found a requirement for the RuvAB branch migrase. Our results also indicate that the mechanism of switching at vlsE in B. burgdorferi is distinct from switching at pilE in N. gonorrhoeae, which is the only other organism analyzed genetically in detail. Finally, our findings suggest a unique mechanism for switching at vlsE and a role for currently unidentified B. burgdorferi proteins in this process.
Collapse
Affiliation(s)
- Ashley R. Dresser
- Department of Biochemistry & Molecular Biology, The University of Calgary, Calgary, Alberta, Canada
| | - Pierre-Olivier Hardy
- Department of Microbiology & Infectious Diseases, The University of Calgary, Calgary, Alberta, Canada
| | - George Chaconas
- Department of Biochemistry & Molecular Biology, The University of Calgary, Calgary, Alberta, Canada
- Department of Microbiology & Infectious Diseases, The University of Calgary, Calgary, Alberta, Canada
- * E-mail:
| |
Collapse
|
47
|
Medrano MS, Policastro PF, Schwan TG, Coburn J. Interaction of Borrelia burgdorferi Hbb with the p66 promoter. Nucleic Acids Res 2009; 38:414-27. [PMID: 19910373 PMCID: PMC2811001 DOI: 10.1093/nar/gkp1027] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Borrelia burgdorferi, an agent of Lyme disease, encodes the β3-chain integrin ligand P66. P66 is expressed by B. burgdorferi in the mammal, in laboratory media, and as the bacteria are acquired or transmitted by the tick, but is not expressed by the bacterium in unfed ticks. Attempts to reveal factors influencing expression revealed that P66 was expressed in all in vitro conditions investigated. Candidate regulators identified in a search of the B. burgdorferi genome for homologs to other bacterial transcription factors were cloned and introduced into E. coli carrying a p66 promoter-signal sequence-phoA (alkaline phosphatase, or AP) fusion. Three candidate transcription factors—two that decreased AP activity (Hbb and BB0527), and one that increased AP activity (BBA23)—were identified. BBA23 and BB0527 did not bind to the p66 promoter at physiologically relevant concentrations. In contrast, several promoter fragments, including p66, were bound by Hbb (BB0232), with slightly different affinities. Consistent with results from other laboratories, Hbb appears to recognize multiple DNA sequences. Changes in the expression of p66 and bb0232 in the tick at various points with respect to feeding on mice, along with the results of the reporter experiment in the surrogate host E. coli, are consistent with Hbb/BB0232 being involved in regulating p66 expression.
Collapse
Affiliation(s)
- Melisa S Medrano
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA 02111, USA
| | | | | | | |
Collapse
|
48
|
Moriarty TJ, Chaconas G. Identification of the determinant conferring permissive substrate usage in the telomere resolvase, ResT. J Biol Chem 2009; 284:23293-301. [PMID: 19561077 DOI: 10.1074/jbc.m109.023549] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Linear genome stability requires specialized telomere replication and protection mechanisms. A common solution to this problem in non-eukaryotes is the formation of hairpin telomeres by telomere resolvases (also known as protelomerases). These enzymes perform a two-step transesterification on replication intermediates to generate hairpin telomeres using an active site similar to that of tyrosine recombinases and type IB topoisomerases. Unlike phage telomere resolvases, the telomere resolvase from the Lyme disease pathogen Borrelia burgdorferi (ResT) is a permissive enzyme that resolves several types of telomere in vitro. However, the ResT region and residues mediating permissive substrate usage have not been identified. The relapsing fever Borrelia hermsii ResT exhibits a more restricted substrate usage pattern than B. burgdorferi ResT and cannot efficiently resolve a Type 2 telomere. In this study, we determined that all relapsing fever ResTs process Type 2 telomeres inefficiently. Using a library of chimeric and mutant B. hermsii/B. burgdorferi ResTs, we mapped the determinants in B. burgdorferi ResT conferring the ability to resolve multiple Type 2 telomeres. Type 2 telomere resolution was dependent on a single proline in the ResT catalytic region that was conserved in all Lyme disease but not relapsing fever ResTs and that is part of a 2-amino acid insertion absent from phage telomere resolvase sequences. The identification of a permissive substrate usage determinant explains the ability of B. burgdorferi ResT to process the 19 unique telomeres found in its segmented genome and will aid further studies on the structure and function of this essential enzyme.
Collapse
Affiliation(s)
- Tara J Moriarty
- Department of Biochemistry, University of Calgary, Calgary, Alberta, Canada
| | | |
Collapse
|
49
|
Riley SP, Bykowski T, Cooley AE, Burns LH, Babb K, Brissette CA, Bowman A, Rotondi M, Miller MC, DeMoll E, Lim K, Fried MG, Stevenson B. Borrelia burgdorferi EbfC defines a newly-identified, widespread family of bacterial DNA-binding proteins. Nucleic Acids Res 2009; 37:1973-83. [PMID: 19208644 PMCID: PMC2665219 DOI: 10.1093/nar/gkp027] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The Lyme disease spirochete, Borrelia burgdorferi, encodes a novel type of DNA-binding protein named EbfC. Orthologs of EbfC are encoded by a wide range of bacterial species, so characterization of the borrelial protein has implications that span the eubacterial kingdom. The present work defines the DNA sequence required for high-affinity binding by EbfC to be the 4 bp broken palindrome GTnAC, where ‘n’ can be any nucleotide. Two high-affinity EbfC-binding sites are located immediately 5′ of B. burgdorferi erp transcriptional promoters, and binding of EbfC was found to alter the conformation of erp promoter DNA. Consensus EbfC-binding sites are abundantly distributed throughout the B. burgdorferi genome, occurring approximately once every 1 kb. These and other features of EbfC suggest that this small protein and its orthologs may represent a distinctive type of bacterial nucleoid-associated protein. EbfC was shown to bind DNA as a homodimer, and site-directed mutagenesis studies indicated that EbfC and its orthologs appear to bind DNA via a novel α-helical ‘tweezer’-like structure.
Collapse
Affiliation(s)
- Sean P Riley
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky College of Medicine, Lexington, KY 40536-0298, USA
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
50
|
Peng X, Pigli YZ, Rice PA, Greenberg MM. Protein binding has a large effect on radical mediated DNA damage. J Am Chem Soc 2008; 130:12890-1. [PMID: 18778053 DOI: 10.1021/ja805440v] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Oxidative DNA damage is important in aging and a variety of diseases. Significant advances have been made in our understanding of the chemistry of radical mediated DNA damage. These studies have been carried out on DNA in the absence of proteins. However, in cells DNA is typically bound by proteins such as in chromatin and transiently by proteins that regulate biochemical processes. How and whether protein binding affects DNA radical reactivity is not well understood. The effect of the DNA binding protein Hbb on the reactivity of the 5-(2'-deoxyuridinyl)methyl radical (1) and 5-(2'-deoxycytidinyl)methyl radical (2) was studied. Hbb bends DNA and disrupts base stacking at the sites of kinking. The reactivity of 1 and 2 are significantly affected when they are generated at the kinking site in the presence of Hbb. The increased conformational mobility of the radicals results in significantly higher yields of DNA interstrand cross-links. These studies provide the first specific data on how protein binding affects the reactivity of a DNA radical and bring us closer to understanding oxidative DNA damage in cells.
Collapse
Affiliation(s)
- Xiaohua Peng
- Department of Chemistry, The Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, USA
| | | | | | | |
Collapse
|