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Diaz A, Ramakrishnan V. Effect of osmolytes on the EcoRI endonuclease: Insights into hydration and protein dynamics from molecular dynamics simulations. Comput Biol Chem 2023; 105:107883. [PMID: 37210944 DOI: 10.1016/j.compbiolchem.2023.107883] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 05/16/2023] [Accepted: 05/16/2023] [Indexed: 05/23/2023]
Abstract
Osmolytes play an important role in cellular physiology by modulating the properties of proteins, including their molecular specificity. EcoRI is a model restriction enzyme whose specificity to DNA is altered in the presence of osmolytes. Here, we investigate the effect of two different osmolytes, glycerol and DMSO, on the dynamics and hydration of the EcoRI enzyme using molecular dynamics simulations. Our results show that the osmolytes, alter the essential dynamics of EcoRI. Particularly, we observe that the dynamics of the arm region of EcoRI which is involved in DNA binding is significantly altered. In addition, conformational free energy analyses reveals that the osmolytes bring about a change in the landscape similar to that of EcoRI bound to cognate DNA. We further observe that the hydration of the enzyme for each of the osmolyte is different, indicating that the mechanism of action of each of these osmolytes could be different. Further analyses of interfacial water dynamics using rotational autocorrelation function reveals that while the protein surface contributes to a slower tumbling motion of water, osmolytes, additionally contribute to the slowing of the angular motion of the water molecules. Entropy analysis also corroborates with this finding. We also find that the slowed rotational motion of interfacial waters in the presence of osmolytes contributes to a slowed relaxation of the hydrogen bonds between the interfacial waters and the functionally important residues in the protein. Taken together, our results show that osmolytes alter the dynamics of the protein by altering the dynamics of water. This altered dynamics, mediated by the changes in the water dynamics and hydrogen bonds with functionally important residues, may contribute to the altered specificity of EcoRI in the presence of osmolytes.
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Affiliation(s)
- Aathithya Diaz
- Computational Molecular Biophysics Laboratory, Bioinformatics Center, School of Chemical & Biotechnology, SASTRA Deemed to be University, Thanjavur 613401, Tamil Nadu, India
| | - Vigneshwar Ramakrishnan
- Computational Molecular Biophysics Laboratory, Bioinformatics Center, School of Chemical & Biotechnology, SASTRA Deemed to be University, Thanjavur 613401, Tamil Nadu, India.
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2
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Kaur R, Nikkel DJ, Aboelnga MM, Wetmore SD. The Impact of DFT Functional, Cluster Model Size, and Implicit Solvation on the Structural Description of Single-Metal-Mediated DNA Phosphodiester Bond Cleavage: The Case Study of APE1. J Phys Chem B 2022; 126:10672-10683. [PMID: 36485014 DOI: 10.1021/acs.jpcb.2c06756] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Phosphodiester bond hydrolysis in nucleic acids is a ubiquitous reaction that can be facilitated by enzymes called nucleases, which often use metal ions to achieve catalytic function. While a two-metal-mediated pathway has been well established for many enzymes, there is growing support that some enzymes require only one metal for the catalytic step. Using human apurinic/apyrimidinic endonuclease (APE1) as a prototypical example and cluster models, this study clarifies the impact of DFT functional, cluster model size, and implicit solvation on single-metal-mediated phosphodiester bond cleavage and provides insight into how to efficiently model this chemistry. Initially, a model containing 69 atoms built from a high-resolution X-ray crystal structure is used to explore the reaction pathway mapped by a range of DFT functionals and basis sets, which provides support for the use of standard functionals (M06-2X and B3LYP-D3) to study this reaction. Subsequently, systematically increasing the model size to 185 atoms by including additional amino acids and altering residue truncation points highlights that small models containing only a few amino acids or β carbon truncation points introduce model strains and lead to incorrect metal coordination. Indeed, a model that contains all key residues (general base and acid, residues that stabilize the substrate, and amino acids that maintain the metal coordination) is required for an accurate structural depiction of the one-metal-mediated phosphodiester bond hydrolysis by APE1, which results in 185 atoms. The additional inclusion of the broader enzyme environment through continuum solvation models has negligible effects. The insights gained in the present work can be used to direct future computational studies of other one-metal-dependent nucleases to provide a greater understanding of how nature achieves this difficult chemistry.
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Affiliation(s)
- Rajwinder Kaur
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta T1K 3M4, Canada
| | - Dylan J Nikkel
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta T1K 3M4, Canada
| | - Mohamed M Aboelnga
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta T1K 3M4, Canada.,Chemistry Department, Faculty of Science, Damietta University, New Damietta 34517, Egypt
| | - Stacey D Wetmore
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta T1K 3M4, Canada
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3
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Walkowiak JJ, Ballauff M. Interaction of Polyelectrolytes with Proteins: Quantifying the Role of Water. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:2100661. [PMID: 34194953 PMCID: PMC8224434 DOI: 10.1002/advs.202100661] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 03/29/2021] [Indexed: 05/11/2023]
Abstract
A theoretical model is presented for the free energy ΔGb of complex formation between a highly charged polyelectrolyte and a protein. The model introduced here comprises both the effect of released counterions and the uptake or release of water molecules during complex formation. The resulting expression for ΔGb is hence capable of describing the dependence of ΔGb on temperature as well as on the concentration of salt in the system: An increase of the salt concentration in the solution increases the activity of the ions and counterion release becomes less effective for binding. On the other hand, an increased salt concentration leads to the decrease of the activity of water in bulk. Hence, release of water molecules during complex formation will be more advantageous and lead to an increase of the magnitude of ΔGb and the binding constant. It is furthermore demonstrated that the release or uptake of water molecules is the origin of the marked enthalpy-entropy cancellation observed during complex formation of polyelectrolytes with proteins. The comparison with experimental data on complex formation between a synthetic (sulfated dendritic polyglycerol) and natural polyelectrolytes (DNA; heparin) with proteins shows full agreement with theory.
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Affiliation(s)
- Jacek J. Walkowiak
- Institut für Chemie und BiochemieFreie Universität BerlinTaktstraße 3Berlin14195Germany
- Aachen‐Maastricht Institute for Biobased MaterialsMaastricht UniversityBrightlands Chemelot Campus, Urmonderbaan 22Geleen6167 RDThe Netherlands
| | - Matthias Ballauff
- Institut für Chemie und BiochemieFreie Universität BerlinTaktstraße 3Berlin14195Germany
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4
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The Swiss army knife of time series data mining: ten useful things you can do with the matrix profile and ten lines of code. Data Min Knowl Discov 2020. [DOI: 10.1007/s10618-019-00668-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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5
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Second-Shell Basic Residues Expand the Two-Metal-Ion Architecture of DNA and RNA Processing Enzymes. Structure 2017; 26:40-50.e2. [PMID: 29225080 PMCID: PMC5758106 DOI: 10.1016/j.str.2017.11.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 09/12/2017] [Accepted: 11/12/2017] [Indexed: 02/01/2023]
Abstract
Synthesis and scission of phosphodiester bonds in DNA and RNA regulate vital processes within the cell. Enzymes that catalyze these reactions operate mostly via the recognized two-metal-ion mechanism. Our analysis reveals that basic amino acids and monovalent cations occupy structurally conserved positions nearby the active site of many two-metal-ion enzymes for which high-resolution (<3 Å) structures are known, including DNA and RNA polymerases, nucleases such as Cas9, and splicing ribozymes. Integrating multiple-sequence and structural alignments with molecular dynamics simulations, electrostatic potential maps, and mutational data, we found that these elements always interact with the substrates, suggesting that they may play an active role for catalysis, in addition to their electrostatic contribution. We discuss possible mechanistic implications of this expanded two-metal-ion architecture, including inferences on medium-resolution cryoelectron microscopy structures. Ultimately, our analysis may inspire future experiments and strategies for enzyme engineering or drug design to modulate nucleic acid processing. Basic residues in the active site of two-metal-ion enzymes are structurally conserved These residues are also conserved in evolution Mutagenesis suggests these residues may exert an effect on DNA- and RNA processing Our work offers insights into CRISPR/Cas9, spliceosome, and DNA/RNA polymerases
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6
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Ramachandrakurup S, Ammapalli S, Ramakrishnan V. Investigating the effect of charged amino acids on DNA conformation in EcoRI-DNA complex: a molecular dynamics simulation study. J Biomol Struct Dyn 2016; 35:3540-3554. [PMID: 27935429 DOI: 10.1080/07391102.2016.1261741] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Sequence-specific binding of proteins to DNA is essential for almost all the cellular processes like transcription, translation, replication, etc. One among the various mechanisms that has been identified so far that contributes to the specificity in protein-DNA interaction is the DNA conformational change. Electrostatic neutralization of the phosphate groups by the positively charged amino acid residues in proteins is thought to bring about such conformational changes in DNA. Here, we employ molecular dynamics simulations to examine the effect of charge on amino acids Lys113, Arg145, and Asp91 which are attached to the scissile phosphate on the conformation of DNA in EcoRI-DNA complex. The results indicate that the charge of these amino acids is essential for maintaining the local conformation of DNA in the EcoRI-bound form. Interestingly, we observe that the positively charged amino acids Lys113 and Arg145 have a long-range influence on the DNA conformation, whereas the negatively charged amino acid Asp91 has only a localized effect on the DNA conformation. The charge on the amino acids also alters the collective dynamics of EcoRI. Collectively, the results shed light on the diversity of the effect of charges on DNA conformation as well as on protein dynamics.
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Affiliation(s)
| | - Sumanth Ammapalli
- a School of Chemical and Biotechnology , SASTRA University , Thanjavur 613401 , India
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7
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Kurian P, Dunston G, Lindesay J. How quantum entanglement in DNA synchronizes double-strand breakage by type II restriction endonucleases. J Theor Biol 2016; 391:102-12. [PMID: 26682627 PMCID: PMC4746125 DOI: 10.1016/j.jtbi.2015.11.018] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2015] [Revised: 10/29/2015] [Accepted: 11/15/2015] [Indexed: 10/22/2022]
Abstract
Macroscopic quantum effects in living systems have been studied widely in pursuit of fundamental explanations for biological energy transport and sensing. While it is known that type II endonucleases, the largest class of restriction enzymes, induce DNA double-strand breaks by attacking phosphodiester bonds, the mechanism by which simultaneous cutting is coordinated between the catalytic centers remains unclear. We propose a quantum mechanical model for collective electronic behavior in the DNA helix, where dipole-dipole oscillations are quantized through boundary conditions imposed by the enzyme. Zero-point modes of coherent oscillations would provide the energy required for double-strand breakage. Such quanta may be preserved in the presence of thermal noise by the enzyme's displacement of water surrounding the DNA recognition sequence. The enzyme thus serves as a decoherence shield. Palindromic mirror symmetry of the enzyme-DNA complex should conserve parity, because symmetric bond-breaking ceases when the symmetry of the complex is violated or when physiological parameters are perturbed from optima. Persistent correlations in DNA across longer spatial separations-a possible signature of quantum entanglement-may be explained by such a mechanism.
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Affiliation(s)
- P Kurian
- National Human Genome Center, Howard University College of Medicine, Washington, DC 20059, USA; Department of Physics and Astronomy, Howard University, Washington, DC 20059, USA; Computational Physics Laboratory, Howard University, Washington, DC 20059, USA.
| | - G Dunston
- National Human Genome Center, Howard University College of Medicine, Washington, DC 20059, USA; Department of Microbiology, Howard University College of Medicine, Washington, DC 20059, USA
| | - J Lindesay
- Department of Physics and Astronomy, Howard University, Washington, DC 20059, USA; Computational Physics Laboratory, Howard University, Washington, DC 20059, USA
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8
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Zaremba M, Siksnys V. An Engineered SS Bridge Blocks the Conformational Change Required for the Nuclease Activity of BfiI. Biochemistry 2015; 54:5340-7. [PMID: 26261897 DOI: 10.1021/acs.biochem.5b00437] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The type IIS restriction endonuclease BfiI is a homodimer, and each monomer is composed of the N-terminal catalytic and C-terminal DNA recognition domains connected by a 28-residue linker segment. In the crystal in the absence of cognate DNA, BfiI exists in a "closed" conformation, in which an interdomain linker occludes a putative DNA binding surface at the catalytic domain and sterically hinders access to the active site. Cognate DNA binding presumably triggers a conformational change from the inactive "closed" state to the catalytically competent "open" state. Here we show that the disulfide SS bridge engineered at the domain interface locks the enzyme in the "closed" state. In the "closed" SS-linked state, BfiI binds cognate DNA with the same affinity as the wild-type enzyme but does not cut it, indicating that cross-linking introduces a restraint on the conformational transition, which couples DNA recognition and cleavage. Disruption of the interdomain SS bridge by the reducing agent restores the DNA cleavage ability of BfiI.
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Affiliation(s)
- Mindaugas Zaremba
- Institute of Biotechnology, Vilnius University , Graiciuno 8, Vilnius LT-02241, Lithuania
| | - Virginijus Siksnys
- Institute of Biotechnology, Vilnius University , Graiciuno 8, Vilnius LT-02241, Lithuania
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9
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Zhang J, Shi Z, Jin Y. Enzyme-free and label-free signal amplification for monitoring endonuclease activity and inhibition via hybridization chain reaction. Analyst 2015; 140:3500-6. [DOI: 10.1039/c5an00304k] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
A facile and sensitive method for studying EcoRI activity and inhibition had been developed based on EcoRI-triggered hybridization chain reaction.
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Affiliation(s)
- Jing Zhang
- Key Laboratory of Applied Surface and Colloid Chemistry
- Ministry of Education
- Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province
- School of Chemistry and Chemical Engineering
- Shaanxi Normal University
| | - Zhilu Shi
- Key Laboratory of Applied Surface and Colloid Chemistry
- Ministry of Education
- Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province
- School of Chemistry and Chemical Engineering
- Shaanxi Normal University
| | - Yan Jin
- Key Laboratory of Applied Surface and Colloid Chemistry
- Ministry of Education
- Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province
- School of Chemistry and Chemical Engineering
- Shaanxi Normal University
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10
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Ji M, Tan L, Jen-Jacobson L, Saxena S. Insights into copper coordination in the EcoRI-DNA complex by ESR spectroscopy. Mol Phys 2014; 112:3173-3182. [PMID: 25750461 PMCID: PMC4350447 DOI: 10.1080/00268976.2014.934313] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The EcoRI restriction endonuclease requires one divalent metal ion in each of two symmetrical and identical catalytic sites to catalyse double-strand DNA cleavage. Recently, we showed that Cu2+ binds outside the catalytic sites to a pair of new sites at H114 in each sub-unit, and inhibits Mg2+ -catalysed DNA cleavage. In order to provide more detailed structural information on this new metal ion binding site, we performed W-band (~94 GHz) and X-band (~9.5 GHz) electron spin resonance spectroscopic measurements on the EcoRI-DNA-(Cu2+ )2 complex. Cu2+ binding results in two distinct components with different gzz and Azz values. X-band electron spin echo envelope modulation results indicate that both components arise from a Cu2+ coordinated to histidine. This observation is further confirmed by the hyperfine sub-level correlation results. W-band electron nuclear double resonance spectra provide evidence for equatorial coordination of water molecules to the Cu2+ ions.
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Affiliation(s)
- Ming Ji
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, USA
| | - Likun Tan
- Division of Engineering and Applied Science, California Institute of Technology, Pasadena, CA, USA
| | - Linda Jen-Jacobson
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, USA
| | - Sunil Saxena
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, USA
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11
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Stryjewska A, Kiepura K, Librowski T, Lochyński S. Biotechnology and genetic engineering in the new drug development. Part II. Monoclonal antibodies, modern vaccines and gene therapy. Pharmacol Rep 2014; 65:1086-101. [PMID: 24399705 DOI: 10.1016/s1734-1140(13)71467-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Revised: 05/13/2013] [Indexed: 12/01/2022]
Abstract
Monoclonal antibodies, modern vaccines and gene therapy have become a major field in modern biotechnology, especially in the area of human health and fascinating developments achieved in the past decades are impressive examples of an interdisciplinary interplay between medicine, biology and engineering. Among the classical products from cells one can find viral vaccines, monoclonal antibodies, and interferons, as well as recombinant therapeutic proteins. Gene therapy opens up challenging new areas. In this review, a definitions of these processes are given and fields of application and products, as well as the future prospects, are discussed.
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Affiliation(s)
- Agnieszka Stryjewska
- Department of Bioorganic Chemistry, Faculty of Chemistry, Wrocław University of Technology, Wyb. Wyspiańskiego 27, PL 50-370 Wrocław, Poland. ;
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12
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Stryjewska A, Kiepura K, Librowski T, Lochyński S. Biotechnology and genetic engineering in the new drug development. Part I. DNA technology and recombinant proteins. Pharmacol Rep 2014; 65:1075-85. [PMID: 24399704 DOI: 10.1016/s1734-1140(13)71466-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Revised: 05/13/2013] [Indexed: 11/17/2022]
Abstract
Pharmaceutical biotechnology has a long tradition and is rooted in the last century, first exemplified by penicillin and streptomycin as low molecular weight biosynthetic compounds. Today, pharmaceutical biotechnology still has its fundamentals in fermentation and bioprocessing, but the paradigmatic change affected by biotechnology and pharmaceutical sciences has led to an updated definition. The biotechnology revolution redrew the research, development, production and even marketing processes of drugs. Powerful new instruments and biotechnology related scientific disciplines (genomics, proteomics) make it possible to examine and exploit the behavior of proteins and molecules. Recombinant DNA (rDNA) technologies (genetic, protein, and metabolic engineering) allow the production of a wide range of peptides, proteins, and biochemicals from naturally nonproducing cells. This technology, now approximately 25 years old, is becoming one of the most important technologies developed in the 20(th) century. Pharmaceutical products and industrial enzymes were the first biotech products on the world market made by means of rDNA. Despite important advances regarding rDNA applications in mammalian cells, yeasts still represent attractive hosts for the production of heterologous proteins. In this review we describe these processes.
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Affiliation(s)
- Agnieszka Stryjewska
- Department of Bioorganic Chemistry, Faculty of Chemistry, Wrocław University of Technology, Wyb. Wyspiańskiego 27, PL 50-370 Wrocław, Poland. ;
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13
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Pingoud A, Wilson GG, Wende W. Type II restriction endonucleases--a historical perspective and more. Nucleic Acids Res 2014; 42:7489-527. [PMID: 24878924 PMCID: PMC4081073 DOI: 10.1093/nar/gku447] [Citation(s) in RCA: 173] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Revised: 05/02/2014] [Accepted: 05/07/2014] [Indexed: 12/17/2022] Open
Abstract
This article continues the series of Surveys and Summaries on restriction endonucleases (REases) begun this year in Nucleic Acids Research. Here we discuss 'Type II' REases, the kind used for DNA analysis and cloning. We focus on their biochemistry: what they are, what they do, and how they do it. Type II REases are produced by prokaryotes to combat bacteriophages. With extreme accuracy, each recognizes a particular sequence in double-stranded DNA and cleaves at a fixed position within or nearby. The discoveries of these enzymes in the 1970s, and of the uses to which they could be put, have since impacted every corner of the life sciences. They became the enabling tools of molecular biology, genetics and biotechnology, and made analysis at the most fundamental levels routine. Hundreds of different REases have been discovered and are available commercially. Their genes have been cloned, sequenced and overexpressed. Most have been characterized to some extent, but few have been studied in depth. Here, we describe the original discoveries in this field, and the properties of the first Type II REases investigated. We discuss the mechanisms of sequence recognition and catalysis, and the varied oligomeric modes in which Type II REases act. We describe the surprising heterogeneity revealed by comparisons of their sequences and structures.
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Affiliation(s)
- Alfred Pingoud
- Institute of Biochemistry, Justus-Liebig-University Giessen, Heinrich-Buff-Ring 58, D-35392 Giessen, Germany
| | - Geoffrey G Wilson
- New England Biolabs Inc., 240 County Road, Ipswich, MA 01938-2723, USA
| | - Wolfgang Wende
- Institute of Biochemistry, Justus-Liebig-University Giessen, Heinrich-Buff-Ring 58, D-35392 Giessen, Germany
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14
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Ji M, Ruthstein S, Saxena S. Paramagnetic metal ions in pulsed ESR distance distribution measurements. Acc Chem Res 2014; 47:688-95. [PMID: 24289139 DOI: 10.1021/ar400245z] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The use of pulsed electron spin resonance (ESR) to measure interspin distance distributions has advanced biophysical research. The three major techniques that use pulsed ESR are relaxation rate based distance measurements, double quantum coherence (DQC), and double electron electron resonance (DEER). Among these methods, the DEER technique has become particularly popular largely because it is easy to implement on commercial instruments and because programs are available to analyze experimental data. Researchers have widely used DEER to measure the structure and conformational dynamics of molecules labeled with the methanethiosulfonate spin label (MTSSL). Recently, researchers have exploited endogenously bound paramagnetic metal ions as spin probes as a way to determine structural constraints in metalloproteins. In this context Cu(2+) has served as a useful paramagnetic metal probe at X-band for DEER based distance measurements. Sample preparation is simple, and a coordinated-Cu(2+) ion offers limited spatial flexibility, making it an attractive probe for DEER experiments. On the other hand, Cu(2+) has a broad absorption ESR spectrum at low temperature, which leads to two potential complications. First, the Cu(2+)-based DEER time domain data has lower signal to noise ratio compared with MTSSL. Second, accurate distance distribution analysis often requires high-quality experimental data at different external magnetic fields or with different frequency offsets. In this Account, we summarize characteristics of Cu(2+)-based DEER distance distribution measurements and data analysis methods. We highlight a novel application of such measurements in a protein-DNA complex to identify the metal ion binding site and to elucidate its chemical mechanism of function. We also survey the progress of research on other metal ions in high frequency DEER experiments.
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Affiliation(s)
- Ming Ji
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Sharon Ruthstein
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
- Department of Chemistry, Faculty of Exact Science, Bar Ilan University, Ramat-Gan 5290002, Israel
| | - Sunil Saxena
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
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15
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Song Y, Zhong D, Luo D, Huang M, Huang Z, Tan H, Sun L, Wang L. Effect of particle size on conformation and enzymatic activity of EcoRI adsorbed on CdS nanoparticles. Colloids Surf B Biointerfaces 2014; 114:269-76. [DOI: 10.1016/j.colsurfb.2013.10.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2013] [Revised: 10/04/2013] [Accepted: 10/14/2013] [Indexed: 10/26/2022]
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16
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Sapienza PJ, Niu T, Kurpiewski MR, Grigorescu A, Jen-Jacobson L. Thermodynamic and structural basis for relaxation of specificity in protein-DNA recognition. J Mol Biol 2014; 426:84-104. [PMID: 24041571 PMCID: PMC3928799 DOI: 10.1016/j.jmb.2013.09.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Revised: 09/03/2013] [Accepted: 09/08/2013] [Indexed: 11/26/2022]
Abstract
As a novel approach to the structural and functional properties that give rise to extremely stringent sequence specificity in protein-DNA interactions, we have exploited "promiscuous" mutants of EcoRI endonuclease to study the detailed mechanism by which changes in a protein can relax specificity. The A138T promiscuous mutant protein binds more tightly to the cognate GAATTC site than does wild-type EcoRI yet displays relaxed specificity deriving from tighter binding and faster cleavage at EcoRI* sites (one incorrect base pair). AAATTC EcoRI* sites are cleaved by A138T up to 170-fold faster than by wild-type enzyme if the site is abutted by a 5'-purine-pyrimidine (5'-RY) motif. When wild-type protein binds to an EcoRI* site, it forms structurally adapted complexes with thermodynamic parameters of binding that differ markedly from those of specific complexes. By contrast, we show that A138T complexes with 5'-RY-flanked AAATTC sites are virtually indistinguishable from wild-type-specific complexes with respect to the heat capacity change upon binding (∆C°P), the change in excluded macromolecular volume upon association, and contacts to the phosphate backbone. While the preference for the 5'-RY motif implicates contacts to flanking bases as important for relaxed specificity, local effects are not sufficient to explain the large differences in ∆C°P and excluded volume, as these parameters report on global features of the complex. Our findings therefore support the view that specificity does not derive from the additive effects of individual interactions but rather from a set of cooperative events that are uniquely associated with specific recognition.
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Affiliation(s)
- Paul J Sapienza
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Tianyi Niu
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Michael R Kurpiewski
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Arabela Grigorescu
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Linda Jen-Jacobson
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA.
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ESR spectroscopy identifies inhibitory Cu2+ sites in a DNA-modifying enzyme to reveal determinants of catalytic specificity. Proc Natl Acad Sci U S A 2012; 109:E993-1000. [PMID: 22493217 DOI: 10.1073/pnas.1200733109] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The relationship between DNA sequence recognition and catalytic specificity in a DNA-modifying enzyme was explored using paramagnetic Cu(2+) ions as probes for ESR spectroscopic and biochemical studies. Electron spin echo envelope modulation spectroscopy establishes that Cu(2+) coordinates to histidine residues in the EcoRI endonuclease homodimer bound to its specific DNA recognition site. The coordinated His residues were identified by a unique use of Cu(2+)-ion based long-range distance constraints. Double electron-electron resonance data yield Cu(2+)-Cu(2+) and Cu(2+)-nitroxide distances that are uniquely consistent with one Cu(2+) bound to His114 in each subunit. Isothermal titration calorimetry confirms that two Cu(2+) ions bind per complex. Unexpectedly, Mg(2+)-catalyzed DNA cleavage by EcoRI is profoundly inhibited by Cu(2+) binding at these hitherto unknown sites, 13 Å away from the Mg(2+) positions in the catalytic centers. Molecular dynamics simulations suggest a model for inhibition of catalysis, whereby the Cu(2+) ions alter critical protein-DNA interactions and water molecule positions in the catalytic sites. In the absence of Cu(2+), the Mg(2+)-dependence of EcoRI catalysis shows positive cooperativity, which would enhance EcoRI inactivation of foreign DNA by irreparable double-strand cuts, in preference to readily repaired single-strand nicks. Nonlinear Poisson-Boltzmann calculations suggest that this cooperativity arises because the binding of Mg(2+) in one catalytic site makes the surface electrostatic potential in the distal catalytic site more negative, thus enhancing binding of the second Mg(2+). Taken together, our results shed light on the structural and electrostatic factors that affect site-specific catalysis by this class of endonucleases.
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Ramakrishnan V, Jagannathan S, Shaikh AR, Rajagopalan R. Dynamic and Structural Changes in the Minimally Restructuring EcoRI Bound to a Minimally Mutated DNA Chain. J Biomol Struct Dyn 2012; 29:743-56. [DOI: 10.1080/073911012010525020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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19
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Metal ion and DNA binding by single-chain PvuII endonuclease: lessons from the linker. J Biol Inorg Chem 2011; 16:1269-78. [PMID: 21725852 DOI: 10.1007/s00775-011-0814-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2011] [Accepted: 06/23/2011] [Indexed: 10/18/2022]
Abstract
Understanding the roles of metal ions in restriction enzymes has been complicated by both the presence of two metal ions in many active sites and their homodimeric structure. Using a single-chain form of the wild-type restriction enzyme PvuII (scWT) in which subunits are fused with a short polypeptide linker (Simoncsits et al. in J. Mol. Biol. 309:89-97, 2001), we have characterized metal ion and DNA binding behavior in one subunit and examined the effects of the linker on dimer behavior. scWT exhibits heteronuclear single quantum coherence NMR spectra similar to those of native wild-type PvuII (WT). For scWT, isothermal titration calorimetry data fit to two Ca(II) sites per subunit with low-millimolar K (d)s. The variant scWT|E68A, in which metal ion binding in one subunit is abolished by mutation, also binds two Ca(II) ions in the WT subunit with low-millimolar K (d)s. When there are no added metal ions, DNA binding affinity for scWT is tenfold stronger than that of the native WT, but tenfold weaker at saturating Ca(II) concentration. In the presence of Ca(II), scWT|E68A binds target DNA similarly to scWT, indicating that high-affinity substrate binding can be carried energetically by one metal-ion-binding subunit. Global analysis of DNA binding data for scWT|E68A suggests that the metal-ion-dependent behaviors observed for WT are reflective of independent subunit behavior. This characterization provides an understanding of subunit contributions in a homodimeric context.
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Olorunniji FJ, Stark WM. The catalytic residues of Tn3 resolvase. Nucleic Acids Res 2009; 37:7590-602. [PMID: 19789272 PMCID: PMC2794168 DOI: 10.1093/nar/gkp797] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2009] [Revised: 09/08/2009] [Accepted: 09/09/2009] [Indexed: 11/16/2022] Open
Abstract
To characterize the residues that participate in the catalysis of DNA cleavage and rejoining by the site-specific recombinase Tn3 resolvase, we mutated conserved polar or charged residues in the catalytic domain of an activated resolvase variant. We analysed the effects of mutations at 14 residues on proficiency in binding to the recombination site ('site I'), formation of a synaptic complex between two site Is, DNA cleavage and recombination. Mutations of Y6, R8, S10, D36, R68 and R71 resulted in greatly reduced cleavage and recombination activity, suggesting crucial roles of these six residues in catalysis, whereas mutations of the other residues had less dramatic effects. No mutations strongly inhibited binding of resolvase to site I, but several caused conspicuous changes in the yield or stability of the synapse of two site Is observed by non-denaturing gel electrophoresis. The involvement of some residues in both synapsis and catalysis suggests that they contribute to a regulatory mechanism, in which engagement of catalytic residues with the substrate is coupled to correct assembly of the synapse.
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Affiliation(s)
| | - W. Marshall Stark
- Faculty of Biomedical and Life Sciences, University of Glasgow, Bower Building, Glasgow G12 8QQ, Scotland, UK
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21
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Wozniak LA, Bukowiecka-Matusiak M, Burzynska-Pedziwatr I, Stec WJ. Stereodefined dinucleoside (3′,5′)-propionamidophosphonates and β-cyanoethylphosphonates and their incorporation into modified oligonucleotides. Tetrahedron Lett 2009. [DOI: 10.1016/j.tetlet.2009.01.153] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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22
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Fabrication of the nanogapped gold nanoparticles film for direct electrical detection of DNA and EcoRI endonuclease. Colloids Surf B Biointerfaces 2009; 69:99-104. [DOI: 10.1016/j.colsurfb.2008.11.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2008] [Revised: 11/14/2008] [Accepted: 11/14/2008] [Indexed: 11/22/2022]
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23
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Label-free monitoring of site-specific DNA cleavage by EcoRI endonuclease using cyclic voltammetry and electrochemical impedance. Anal Chim Acta 2009; 634:44-8. [DOI: 10.1016/j.aca.2008.12.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2008] [Revised: 12/02/2008] [Accepted: 12/02/2008] [Indexed: 11/20/2022]
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24
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Nakonieczna J, Kaczorowski T, Obarska-Kosinska A, Bujnicki JM. Functional analysis of MmeI from methanol utilizer Methylophilus methylotrophus, a subtype IIC restriction-modification enzyme related to type I enzymes. Appl Environ Microbiol 2009; 75:212-23. [PMID: 18997032 PMCID: PMC2612229 DOI: 10.1128/aem.01322-08] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2008] [Accepted: 10/29/2008] [Indexed: 11/20/2022] Open
Abstract
MmeI from Methylophilus methylotrophus belongs to the type II restriction-modification enzymes. It recognizes an asymmetric DNA sequence, 5'-TCCRAC-3' (R indicates G or A), and cuts both strands at fixed positions downstream of the specific site. This particular feature has been exploited in transcript profiling of complex genomes (using serial analysis of gene expression technology). We have shown previously that the endonucleolytic activity of MmeI is strongly dependent on the presence of S-adenosyl-l-methionine (J. Nakonieczna, J. W. Zmijewski, B. Banecki, and A. J. Podhajska, Mol. Biotechnol. 37:127-135, 2007), which puts MmeI in subtype IIG. The same cofactor is used by MmeI as a methyl group donor for modification of an adenine in the upper strand of the recognition site to N(6)-methyladenine. Both enzymatic activities reside in a single polypeptide (919 amino acids [aa]), which puts MmeI also in subtype IIC of the restriction-modification systems. Based on a molecular model, generated with the use of bioinformatic tools and validated by site-directed mutagenesis, we were able to localize three functional domains in the structure of the MmeI enzyme: (i) the N-terminal portion containing the endonucleolytic domain with the catalytic Mg2+-binding motif D(70)-X(9)-EXK(82), characteristic for the PD-(D/E)XK superfamily of nucleases; (ii) a central portion (aa 310 to 610) containing nine sequence motifs conserved among N(6)-adenine gamma-class DNA methyltransferases; (iii) the C-terminal portion (aa 610 to 919) containing a putative target recognition domain. Interestingly, all three domains showed highest similarity to the corresponding elements of type I enzymes rather than to classical type II enzymes. We have found that MmeI variants deficient in restriction activity (D70A, E80A, and K82A) can bind and methylate specific nucleotide sequence. This suggests that domains of MmeI responsible for DNA restriction and modification can act independently. Moreover, we have shown that a single amino acid residue substitution within the putative target recognition domain (S807A) resulted in a MmeI variant with a higher endonucleolytic activity than the wild-type enzyme.
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Affiliation(s)
- Joanna Nakonieczna
- Department of Biotechnology, Intercollegiate Faculty of Biotechnology, University of Gdansk, and Medical University of Gdansk, Kladki 24, 80-822 Gdansk, Poland.
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25
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Stone K, Townsend J, Sarver J, Sapienza P, Saxena S, Jen-Jacobson L. Electron Spin Resonance Shows Common Structural Features for Different Classes ofEcoRI-DNA Complexes. Angew Chem Int Ed Engl 2008. [DOI: 10.1002/ange.200803588] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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26
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Structural analysis of the heterodimeric type IIS restriction endonuclease R.BspD6I acting as a complex between a monomeric site-specific nickase and a catalytic subunit. J Mol Biol 2008; 384:489-502. [PMID: 18835275 DOI: 10.1016/j.jmb.2008.09.033] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2008] [Revised: 09/10/2008] [Accepted: 09/16/2008] [Indexed: 11/20/2022]
Abstract
The heterodimeric restriction endonuclease R.BspD6I from Bacillus species D6 recognizes a pseudosymmetric sequence and cuts both DNA strands outside the recognition sequence. The large subunit, Nt.BspD6I, acts as a type IIS site-specific monomeric nicking endonuclease. The isolated small subunit, ss.BspD6I, does not bind DNA and is not catalytically active. We solved the crystal structures of Nt.BspD6I and ss.BspD6I at high resolution. Nt.BspD6I consists of three domains, two of which exhibit structural similarity to the recognition and cleavage domains of FokI. ss.BspD6I has a fold similar to that of the cleavage domain of Nt.BspD6I, each containing a PD-(D/E)XK motif and a histidine as an additional putative catalytic residue. In contrast to the DNA-bound FokI structure, in which the cleavage domain is rotated away from the DNA, the crystal structure of Nt.BspD6I shows the recognition and cleavage domains in favorable orientations for interactions with DNA. Docking models of complexes of Nt.BspD6I and R.BspD6I with cognate DNA were constructed on the basis of structural similarity to individual domains of FokI, R.BpuJI and HindIII. A three-helix bundle forming an interdomain linker in Nt.BspD6I acts as a rigid spacer adjusting the orientations of the spatially separated domains to match the distance between the recognition and cleavage sites accurately.
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27
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VanderVeen LA, Harris TM, Jen-Jacobson L, Marnett LJ. Formation of DNA-protein cross-links between gamma-hydroxypropanodeoxyguanosine and EcoRI. Chem Res Toxicol 2008; 21:1733-8. [PMID: 18690724 PMCID: PMC2651693 DOI: 10.1021/tx800092g] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The toxicity of acrolein, an alpha,beta-unsaturated aldehyde produced during lipid peroxidation, is attributable to its high reactivity toward DNA and cellular proteins. The major acrolein-DNA adduct, gamma-hydroxypropano-2'-deoxyguanosine (gamma-HOPdG), ring opens to form a reactive N(2)-oxopropyl moiety that cross-links to DNA and proteins. We demonstrate the ability of gamma-HOPdG in a duplex oligonucleotide to cross-link to a protein (EcoRI) that specifically interacts with DNA at a unique sequence. The formation of a cross-link to EcoRI was dependent on the intimate binding of the enzyme to its gamma-HOPdG-modified recognition site. Interestingly, the cross-link did not restrict the ability of EcoRI to cleave DNA substrates. However, stabilization of the cross-link by reduction of the Schiff base linkage resulted in loss of enzyme activity. This work indicates that the gamma-HOPdG-EcoRI cross-link is in equilibrium with free oligonucleotide and enzyme. Reversal of cross-link formation allows EcoRI to effect enzymatic cleavage of competitor oligonucleotides.
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Affiliation(s)
- Laurie A VanderVeen
- A. B. Hancock Jr. Memorial Laboratory for Cancer Research, Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
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28
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Sapienza PJ, Rosenberg JM, Jen-Jacobson L. Structural and thermodynamic basis for enhanced DNA binding by a promiscuous mutant EcoRI endonuclease. Structure 2008; 15:1368-82. [PMID: 17997963 DOI: 10.1016/j.str.2007.09.014] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2007] [Revised: 08/23/2007] [Accepted: 09/03/2007] [Indexed: 10/22/2022]
Abstract
Promiscuous mutant EcoRI endonucleases bind to the canonical site GAATTC more tightly than does the wild-type endonuclease, yet cleave variant (EcoRI(*)) sites more rapidly than does wild-type. The crystal structure of the A138T promiscuous mutant homodimer in complex with a GAATTC site is nearly identical to that of the wild-type complex, except that the Thr138 side chains make packing interactions with bases in the 5'-flanking regions outside the recognition hexanucleotide while excluding two bound water molecules seen in the wild-type complex. Molecular dynamics simulations confirm exclusion of these waters. The structure and simulations suggest possible reasons why binding of the A138T protein to the GAATTC site has DeltaS degrees more favorable and DeltaH degrees less favorable than for wild-type endonuclease binding. The interactions of Thr138 with flanking bases may permit A138T, unlike wild-type enzyme, to form complexes with EcoRI(*) sites that structurally resemble the specific wild-type complex with GAATTC.
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Affiliation(s)
- Paul J Sapienza
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
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29
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Whiteson KL, Rice PA. Binding and catalytic contributions to site recognition by flp recombinase. J Biol Chem 2008; 283:11414-23. [PMID: 18276592 DOI: 10.1074/jbc.m800106200] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Flp catalyzes site-specific recombination in a highly sequence-specific manner despite making few direct contacts to the bases within its binding site. Sequence discrimination could take place in the binding and/or the catalytic steps. In this study, we independently measure the binding affinity and initial cleavage rate of Flp recombinase with approximately 20 designed alternate target DNA sequences. Our results show that Flp specificity is largely, although not entirely, imparted at the binding step and is the result of a combination of direct and indirect readout. The Flp binding site includes an A/T-rich region that displays a characteristically narrow minor groove. We find that many A --> T changes are tolerated at the binding step, whereas C or G substitutions tend to decrease binding affinity. The effects of the latter can be alleviated by replacing guanine with inosine, which removes the N2 amino group that protrudes into the minor groove. Some A --> T changes reduce binding affinity, due to clashing with nearby residues, reinforcing that specificity requires avoiding negative contacts as well as creating positive ones. A tracts, which can lead to unusually rigid DNA structure, are tolerated during the binding step when placed within the region where the minor groove is already narrow. However, most A tracts slow catalysis more than C or G substitutions. Understanding what kind of sequence variation is tolerated in the binding and catalytic steps helps us understand how the target DNA is recognized by Flp and will be useful in guiding the design of Flp variants with altered specificities.
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Affiliation(s)
- Katrine L Whiteson
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, Illinois 60637, USA
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30
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Youngblood B, Buller F, Reich NO. Determinants of sequence-specific DNA methylation: target recognition and catalysis are coupled in M.HhaI. Biochemistry 2008; 45:15563-72. [PMID: 17176077 DOI: 10.1021/bi061414t] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Sequence specificity studies of the wild-type bacterial DNA cytosine C5 methyltransferase HhaI were carried out with cognate (5'GCGC3') and noncognate DNA substrates containing single base pair changes at the first and the fourth position (underlined). Specificity for noncognate site methylation at the level of kcat/KDDNA is decreased 9000-80000-fold relative to the cognate site, manifested through changes in methylation, or a prior step, and changes in KDDNA. Analysis of a new high-resolution enzyme-DNA cocrystal structure provides a partial mechanistic understanding of this discrimination. To probe the significance of conformational transitions occurring prior to catalysis in determining specificity, we analyzed the double mutant (H127A/T132A). These amino acid substitutions disrupt the interface between the flexible loop (residues 80-99), which interacts with the DNA minor groove, and the active site. The mutant's methylation of the cognate site is essentially unchanged, yet its methylation of noncognate sites is decreased up to 460-fold relative to the wild-type enzyme. We suggest that a significant contribution to M.HhaI's specificity involves the stabilization of reaction intermediates prior to methyl transfer, mediated by DNA minor groove-protein flexible loop interactions.
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Affiliation(s)
- Ben Youngblood
- Department of Chemistry and Biochemistry and Program in Biomolecular Science and Engineering, University of California, Santa Barbara, California 93106-9510
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31
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Stone KM, Townsend JE, Sarver J, Sapienza PJ, Saxena S, Jen-Jacobson L. Electron spin resonance shows common structural features for different classes of EcoRI-DNA complexes. Angew Chem Int Ed Engl 2008; 47:10192-4. [PMID: 19021169 PMCID: PMC2792891 DOI: 10.1002/anie.200803588] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Katherine M. Stone
- Department of Chemistry, University of Pittsburgh, 219 Parkman Ave, Pittsburgh, PA 15260
| | - Jacqueline E. Townsend
- Department of Biological Sciences, University of Pittsburgh, 320 Clapp Hall, Pittsburgh, PA 15260
| | - Jessica Sarver
- Department of Chemistry, University of Pittsburgh, 219 Parkman Ave, Pittsburgh, PA 15260
| | - Paul J. Sapienza
- Department of Biological Sciences, University of Pittsburgh, 320 Clapp Hall, Pittsburgh, PA 15260
| | - Sunil Saxena
- Department of Chemistry, University of Pittsburgh, 219 Parkman Ave, Pittsburgh, PA 15260
| | - Linda Jen-Jacobson
- Department of Biological Sciences, University of Pittsburgh, 320 Clapp Hall, Pittsburgh, PA 15260
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32
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Mones L, Kulhánek P, Florián J, Simon I, Fuxreiter M. Probing the two-metal ion mechanism in the restriction endonuclease BamHI. Biochemistry 2007; 46:14514-23. [PMID: 18020376 DOI: 10.1021/bi701630s] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The choreography of restriction endonuclease catalysis is a long-standing paradigm in molecular biology. Bivalent metal ions are required almost for all PD..D/ExK type enzymes, but the number of cofactors essential for the DNA backbone scission remained ambiguous. On the basis of crystal structures and biochemical data for various restriction enzymes, three models have been developed that assign critical roles for one, two, or three metal ions during the phosphodiester hydrolysis. To resolve this apparent controversy, we investigated the mechanism of BamHI catalysis using quantum mechanical/molecular mechanical simulation techniques and determined the activation barriers of three possible pathways that involve a Glu-113 or a neighboring water molecule as a general base or an external nucleophile that penetrated from bulk solution. The extrinsic mechanism was found to be the most favorable with an activation free energy of 23.4 kcal/mol, in reasonable agreement with the experimental data. On the basis of the effect of the individual metal ions on the activation barrier, metal ion A was concluded to be pivotal for the reaction, while the enzyme lacking metal ion B still has moderate efficiency. Thus, we propose that the catalytic scheme of BamHI does not involve a general base for nucleophile generation and requires one obligatory metal ion for catalysis that stabilizes the attacking nucleophile and coordinates it throughout the nucleophilic attack. Such a model may also explain the variation in the number of metal ions in the crystal structures and thus could serve as a framework for a unified catalytic scheme of type II restriction endonucleases.
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Affiliation(s)
- Letif Mones
- Institute of Enzymology, Biological Research Center, Hungarian Academy of Sciences, Budapest, Hungary
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33
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Jin Y, Lu W, Hu J, Yao X, Li J. Site-specific DNA cleavage of EcoRI endounclease probed by electrochemical analysis using ferrocene capped gold nanoparticles as reporter. Electrochem commun 2007. [DOI: 10.1016/j.elecom.2006.12.028] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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Chuluunbaatar T, Ivanenko-Johnston T, Fuxreiter M, Meleshko R, Raskó T, Simon I, Heitman J, Kiss A. An EcoRI-RsrI chimeric restriction endonuclease retains parental sequence specificity. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2007; 1774:583-94. [PMID: 17442645 DOI: 10.1016/j.bbapap.2007.02.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2006] [Revised: 02/26/2007] [Accepted: 02/27/2007] [Indexed: 11/16/2022]
Abstract
To test their structural and functional similarity, hybrids were constructed between EcoRI and RsrI, two restriction endonucleases recognizing the same DNA sequence and sharing 50% amino acid sequence identity. One of the chimeric proteins (EERE), in which the EcoRI segment His147-Ala206 was replaced with the corresponding RsrI segment, showed EcoRI/RsrI-specific endonuclease activity. EERE purified from inclusion bodies was found to have approximately 100-fold weaker activity but higher specific DNA binding affinity, than EcoRI. Increased binding is consistent with results of molecular dynamics simulations, which indicate that the number of hydrogen bonds formed with the recognition sequence increased in the chimera as compared to EcoRI. The success of obtaining an EcoRI-RsrI hybrid endonuclease, which differs from EcoRI by 22 RsrI-specific amino acid substitutions and still preserves canonical cleavage specificity, is a sign of structural and functional similarity shared by the parental enzymes. This conclusion is also supported by computational studies, which indicate that construction of the EERE chimera did not induce substantial changes in the structure of EcoRI. Surprisingly, the chimeric endonuclease was more toxic to cells not protected by EcoRI methyltransferase, than the parental EcoRI mutant. Molecular modelling revealed structural alterations, which are likely to impede coupling between substrate recognition and cleavage and suggest a possible explanation for the toxic phenotype.
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Affiliation(s)
- Tungalag Chuluunbaatar
- Institute of Biochemistry, Biological Research Center of the Hungarian Academy of Sciences, P.O. Box 521, 6701 Szeged, Hungary
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35
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Doruker P, Nilsson L, Kurkcuoglu O. Collective dynamics of EcoRI-DNA complex by elastic network model and molecular dynamics simulations. J Biomol Struct Dyn 2006; 24:1-16. [PMID: 16780370 DOI: 10.1080/07391102.2006.10507093] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Anisotropic network model (ANM) is used to analyze the collective motions of restriction enzyme EcoRI in free form and in complex with DNA. For comparison, three independent molecular dynamics (MD) simulations, each of 1.5 ns duration, are also performed for the EcoRI-DNA complex in explicit water. Although high mobility (equilibrium fluctuations) of inner and outer loops that surround the DNA is consistent in both methods and experiments, MD runs sample different conformational subspaces from which reliable collective dynamics cannot be extracted. However, ANM employed on different conformations from MD simulations indicates very similar collective motions. The stems of the inner loops are quite immobile even in the free enzyme and form a large, almost fixed, pocket for DNA binding. As a result, the residues that make specific and non-specific interactions with the DNA exhibit very low fluctuations in the free enzyme. The vibrational entropy difference between the EcoRI complex and free protein + unkinked DNA is positive (favorable), which may partially counteract the unfavorable enthalpy difference of DNA kink formation. Dynamic domains in EcoRI complex and cross-correlations between residue fluctuations indicate possible means of communication between the distal active sites.
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Affiliation(s)
- Pemra Doruker
- Department of Chemical Engineering and Polymer Research Center, Bogazici University, Bebek 34342, Istanbul, Turkey.
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36
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Estabrook RA, Reich N. Observing an Induced-fit Mechanism during Sequence-specific DNA Methylation. J Biol Chem 2006; 281:37205-14. [PMID: 17005571 DOI: 10.1074/jbc.m607538200] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The characterization of conformational changes that drive induced-fit mechanisms and their quantitative importance to enzyme specificity are essential for a full understanding of enzyme function. Here, we report on M.HhaI, a sequence-specific DNA cytosine C(5) methyltransferase that reorganizes a flexible loop (residues 80-100) upon binding cognate DNA as part of an induced-fit mechanism. To directly observe this approximately 26A conformational rearrangement and provide a basis for understanding its importance to specificity, we replaced loop residues Lys-91 and Glu-94 with tryptophans. The double mutants W41F/K91W and W41F/E94W are relatively unperturbed in kinetic and thermodynamic properties. W41F/E94W shows DNA sequence-dependent changes in fluorescence: significant changes in equilibrium and transient state fluorescence that occur when the enzyme binds cognate DNA are absent with nonspecific DNA. These real-time, solution-based results provide direct evidence that binding to cognate DNA induces loop reorganization into the closed conformer, resulting in the correct assembly of the active site. We propose that M.HhaI scans nonspecific DNA in the loop-open conformer and rearranges to the closed form once the cognate site is recognized. The fluorescence data exclude mechanisms in which loop motion precedes base flipping, and we show loop rearrangements are directly coupled to base flipping, because the sequential removal of single hydrogen bonds within the target guanosine:cytosine base pair results in corresponding changes in loop motion.
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Affiliation(s)
- R August Estabrook
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, USA
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Gelato KA, Martin SS, Wong S, Baldwin EP. Multiple levels of affinity-dependent DNA discrimination in Cre-LoxP recombination. Biochemistry 2006; 45:12216-26. [PMID: 17014075 PMCID: PMC2891539 DOI: 10.1021/bi0605235] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Cre recombinase residue Arg259 mediates a canonical bidentate hydrogen-bonded contact with Gua27 of its LoxP DNA substrate. Substituting Cyt8-Gua27 with the three other basepairs, to give LoxAT, LoxTA, and LoxGC, reduced Cre-mediated recombination in vitro, with the preference order of Gua27 > Ade27 approximately Thy27 >> Cyt27. While LoxAT and LoxTA exhibited 2.5-fold reduced affinity and 2.5-5-fold slower reaction rates, LoxGC was a barely functional substrate. Its maximum level of turnover was 6-fold reduced over other substrates, and it exhibited 8.5-fold reduced Cre binding and 6.3-fold slower turnover rate. With LoxP, the rate-limiting step for recombination occurs after protein-DNA complex assembly but before completion of the first strand exchange to form the Holliday junction (HJ) intermediate. With the mutant substrates, it occurs after HJ formation. Using an increased DNA-binding E262Q/E266Q "CreQQ" variant, all four substrates react more readily, but with much less difference between them, and maintained the earlier rate-limiting step. The data indicate that Cre discriminates substrates through differences in (i) concentration dependence of active complex assembly, (ii) turnover rate, and (iii) maximum yield of product at saturation, all of which are functions of the Cre-DNA binding interaction. CreQQ suppression of Lox mutant defects implies that coupling between binding and turnover involves a change in Cre subunit DNA affinities during the "conformational switch" that occurs prior to the second strand exchange. These results provide an example of how a DNA-binding enzyme can exert specificity via affinity modulation of conformational transitions that occur along its reaction pathway.
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Affiliation(s)
| | | | | | - Enoch P. Baldwin
- Corresponding author: Phone: (530) 752-1108. FAX (530) 752-3085.
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Zaremba M, Sasnauskas G, Urbanke C, Siksnys V. Allosteric communication network in the tetrameric restriction endonuclease Bse634I. J Mol Biol 2006; 363:800-12. [PMID: 16987525 DOI: 10.1016/j.jmb.2006.08.050] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2006] [Revised: 08/03/2006] [Accepted: 08/17/2006] [Indexed: 11/20/2022]
Abstract
Restriction endonuclease Bse634I is a homotetramer arranged as a dimer of two primary dimers. Bse634I displays its maximum catalytic efficiency upon binding of two copies of cognate DNA, one per each primary dimer. The catalytic activity of Bse634I on a single DNA copy is down-regulated due to the cross-talking interactions between the primary dimers. The mechanism of signal propagation between the individual active sites of Bse634I remains unclear. To identify communication pathways involved in the catalytic activity regulation of Bse634I tetramer we mutated a selected set of amino acid residues at the dimer-dimer interface and analysed the oligomeric state and catalytic properties of the mutant proteins. We demonstrate that alanine replacement of N262 and V263 residues located in the loop at the tetramerisation interface did not inhibit tetramer assembly but dramatically altered the catalytic properties of Bse634I despite of the distal location from the active site. Kinetic analysis using cognate hairpin oligonucleotide and one and two-site plasmids as substrates allowed us to identify two types of communication signals propagated through the dimer-dimer interface in the Bse634I tetramer: the inhibitory, or "stopper" and the activating, or "sync" signal. We suggest that the interplay between the two signals determines the catalytic and regulatory properties of the Bse634I and mutant proteins.
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Affiliation(s)
- Mindaugas Zaremba
- Institute of Biotechnology, Graiciuno 8, Vilnius, LT-02241, Lithuania
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Nawrot B, Sobczak M, Wójcik M, Janicka M, Nowak M, Cypryk M, Stec WJ. A novel class of DNA analogs bearing 5'-C-phosphonothymidine units: synthesis and physicochemical and biochemical properties. Oligonucleotides 2006; 16:68-82. [PMID: 16584296 DOI: 10.1089/oli.2006.16.68] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
S(C) and R(C) diastereomers of 5'-C-(O,O-diethyl)-phosphonylthymidine ((R)T and (S)T) were used for the synthesis of the dimers T(R)T and T(S)T, respectively. These dimers were incorporated at selected sites in oligonucleotide constructs. Melting temperature (Tm) experiments demonstrated that relative to the unmodified oligodeoxyribonucleotide, the presence of the (R)T moiety reduced the thermal stability of the duplexes by approximately 5.0 degrees C per modification, whereas their (S)T counterparts only slightly destabilized the duplex structure (deltaTm < or = 1 degree C/modification). The stability of the triple-helical complexes containing one, two, or three modified thymidines is slightly higher than that of the parent complex. Nuclease resistance studies performed with snake venom phosphodiesterase, calf spleen phosphodiesterase, and 3'-exonuclease from human plasma showed that cleavage of the oligonucleotides at the site of the modification was completely suppressed regardless of the stereochemistry of the 5'-C-chiral center. The influence of the (R)T and (S)T modification in the recognition sequence of HindIII, EcoRI, and HpaI restriction endonucleases was also investigated. Although the catalytic activity of HindIII was not affected by the presence of the 5'-C-ethoxyphosphonyl modification, the activities of the two remaining restriction enzymes were partially suppressed depending on the site of modification or the stereochemistry of the modification or both ((R)T vs. (S)T).
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Affiliation(s)
- Barbara Nawrot
- Department of Bioorganic Chemistry, Centre of Molecular and Macromolecular Studies of Polish Academy of Sciences, 90-363 Lodz, Poland.
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Wozniak LA, Janicka M, Bukowiecka-Matusiak M. Consequences ofP-Chirality in Chimeric 2′-O-Methyloligoribonucleotides with Stereoregular Methylphosphonothioate Linkages. European J Org Chem 2005. [DOI: 10.1002/ejoc.200500395] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Grazulis S, Manakova E, Roessle M, Bochtler M, Tamulaitiene G, Huber R, Siksnys V. Structure of the metal-independent restriction enzyme BfiI reveals fusion of a specific DNA-binding domain with a nonspecific nuclease. Proc Natl Acad Sci U S A 2005; 102:15797-802. [PMID: 16247004 PMCID: PMC1266039 DOI: 10.1073/pnas.0507949102] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Among all restriction endonucleases known to date, BfiI is unique in cleaving DNA in the absence of metal ions. BfiI represents a different evolutionary lineage of restriction enzymes, as shown by its crystal structure at 1.9-A resolution. The protein consists of two structural domains. The N-terminal catalytic domain is similar to Nuc, an EDTA-resistant nuclease from the phospholipase D superfamily. The C-terminal DNA-binding domain of BfiI exhibits a beta-barrel-like structure very similar to the effector DNA-binding domain of the Mg(2+)-dependent restriction enzyme EcoRII and to the B3-like DNA-binding domain of plant transcription factors. BfiI presumably evolved through domain fusion of a DNA-recognition element to a nonspecific nuclease akin to Nuc and elaborated a mechanism to limit DNA cleavage to a single double-strand break near the specific recognition sequence. The crystal structure suggests that the interdomain linker may act as an autoinhibitor controlling BfiI catalytic activity in the absence of a specific DNA sequence. A psi-blast search identified a BfiI homologue in a Mesorhizobium sp. BNC1 bacteria strain, a plant symbiont isolated from an EDTA-rich environment.
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Affiliation(s)
- Saulius Grazulis
- Laboratory of Protein-DNA Interaction, Institute of Biotechnology, Graiciuno 8, LT-02241 Vilnius, Lithuania.
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Nawrot B, Rębowska B, Cieślińska K, Stec WJ. New approach to the synthesis of oligodeoxyribonucleotides modified with phosphorothioates of predetermined sense of P-chirality. Tetrahedron Lett 2005. [DOI: 10.1016/j.tetlet.2005.07.158] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Ferreiro DU, Dellarole M, Nadra AD, de Prat-Gay G. Free energy contributions to direct readout of a DNA sequence. J Biol Chem 2005; 280:32480-4. [PMID: 16000299 DOI: 10.1074/jbc.m505706200] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The energetic contributions of individual DNA-contacting side chains to specific DNA recognition in the human papillomavirus 16 E2C-DNA complex is small (less than 1.0 kcal mol(-1)), independent of the physical and chemical nature of the interaction, and is strictly additive. The sum of the individual contributions differs 1.0 kcal mol(-1) from the binding energy of the wild-type protein. This difference corresponds to the contribution from the deformability of the DNA, known as "indirect readout." Thus, we can dissect the energetic contribution to DNA binding into 90% direct and 10% indirect readout components. The lack of high energy interactions indicates the absence of "hot spots," such as those found in protein-protein interfaces. These results are compatible with a highly dynamic and "wet" protein-DNA interface, yet highly specific and tight, where individual interactions are constantly being formed and broken.
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Affiliation(s)
- Diego U Ferreiro
- Instituto Leloir, Consejo Nacional de Investigaciones Científicas y Técnicas, and Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina
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Sapienza PJ, Dela Torre CA, McCoy WH, Jana SV, Jen-Jacobson L. Thermodynamic and kinetic basis for the relaxed DNA sequence specificity of "promiscuous" mutant EcoRI endonucleases. J Mol Biol 2005; 348:307-24. [PMID: 15811370 DOI: 10.1016/j.jmb.2005.02.051] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2004] [Revised: 02/15/2005] [Accepted: 02/17/2005] [Indexed: 11/18/2022]
Abstract
Promiscuous mutant EcoRI endonucleases produce lethal to sublethal effects because they cleave Escherichia coli DNA despite the presence of the EcoRI methylase. Three promiscuous mutant forms, Ala138Thr, Glu192Lys and His114Tyr, have been characterized with respect to their binding affinities and first-order cleavage rate constants towards the three classes of DNA sites: specific, miscognate (EcoRI*) and non-specific. We have made the unanticipated and counterintuitive observations that the mutant restriction endonucleases that exhibit relaxed specificity in vivo nevertheless bind more tightly than the wild-type enzyme to the specific recognition sequence in vitro, and show even greater preference for binding to the cognate GAATTC site over miscognate sites. Binding preference for EcoRI* over non-specific DNA is also improved. The first-order cleavage rate constants of the mutant enzymes are normal for the cognate site GAATTC, but are greater than those of the wild-type enzyme at EcoRI* sites. Thus, the mutant enzymes use two mechanisms to partially bypass the multiple fail-safe mechanisms that protect against cleavage of genomic DNA in cells carrying the wild-type EcoRI restriction-modification system: (a) binding to EcoRI* sites is more probable than for wild-type enzyme because non-specific DNA is less effective as a competitive inhibitor; (b) the combination of increased affinity and elevated cleavage rate constants at EcoRI* sites makes double-strand cleavage of these sites a more probable outcome than it is for the wild-type enzyme. Semi-quantitative estimates of rates of EcoRI* site cleavage in vivo, predicted using the binding and cleavage constants measured in vitro, are in accord with the observed lethal phenotypes associated with the three mutations.
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Affiliation(s)
- Paul J Sapienza
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
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