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Ruan S, Tu CH, Bourne CR. Friend or Foe: Protein Inhibitors of DNA Gyrase. BIOLOGY 2024; 13:84. [PMID: 38392303 PMCID: PMC10886550 DOI: 10.3390/biology13020084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 01/20/2024] [Accepted: 01/26/2024] [Indexed: 02/24/2024]
Abstract
DNA gyrase is essential for the successful replication of circular chromosomes, such as those found in most bacterial species, by relieving topological stressors associated with unwinding the double-stranded genetic material. This critical central role makes gyrase a valued target for antibacterial approaches, as exemplified by the highly successful fluoroquinolone class of antibiotics. It is reasonable that the activity of gyrase could be intrinsically regulated within cells, thereby helping to coordinate DNA replication with doubling times. Numerous proteins have been identified to exert inhibitory effects on DNA gyrase, although at lower doses, it can appear readily reversible and therefore may have regulatory value. Some of these, such as the small protein toxins found in plasmid-borne addiction modules, can promote cell death by inducing damage to DNA, resulting in an analogous outcome as quinolone antibiotics. Others, however, appear to transiently impact gyrase in a readily reversible and non-damaging mechanism, such as the plasmid-derived Qnr family of DNA-mimetic proteins. The current review examines the origins and known activities of protein inhibitors of gyrase and highlights opportunities to further exert control over bacterial growth by targeting this validated antibacterial target with novel molecular mechanisms. Furthermore, we are gaining new insights into fundamental regulatory strategies of gyrase that may prove important for understanding diverse growth strategies among different bacteria.
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Affiliation(s)
- Shengfeng Ruan
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK 73019, USA
| | - Chih-Han Tu
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK 73019, USA
| | - Christina R Bourne
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK 73019, USA
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2
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Evaluating the Potential for Cross-Interactions of Antitoxins in Type II TA Systems. Toxins (Basel) 2020; 12:toxins12060422. [PMID: 32604745 PMCID: PMC7354431 DOI: 10.3390/toxins12060422] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 06/18/2020] [Accepted: 06/19/2020] [Indexed: 01/21/2023] Open
Abstract
The diversity of Type-II toxin–antitoxin (TA) systems in bacterial genomes requires tightly controlled interaction specificity to ensure protection of the cell, and potentially to limit cross-talk between toxin–antitoxin pairs of the same family of TA systems. Further, there is a redundant use of toxin folds for different cellular targets and complexation with different classes of antitoxins, increasing the apparent requirement for the insulation of interactions. The presence of Type II TA systems has remained enigmatic with respect to potential benefits imparted to the host cells. In some cases, they play clear roles in survival associated with unfavorable growth conditions. More generally, they can also serve as a “cure” against acquisition of highly similar TA systems such as those found on plasmids or invading genetic elements that frequently carry virulence and resistance genes. The latter model is predicated on the ability of these highly specific cognate antitoxin–toxin interactions to form cross-reactions between chromosomal antitoxins and invading toxins. This review summarizes advances in the Type II TA system models with an emphasis on antitoxin cross-reactivity, including with invading genetic elements and cases where toxin proteins share a common fold yet interact with different families of antitoxins.
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3
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Wang EX, Liu Y, Ma Q, Dong XT, Ding MZ, Yuan YJ. Synthetic cell–cell communication in a three-species consortium for one-step vitamin C fermentation. Biotechnol Lett 2019; 41:951-961. [DOI: 10.1007/s10529-019-02705-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 07/02/2019] [Indexed: 01/04/2023]
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4
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Crystal Structure of VapBC-1 from Nontypeable Haemophilus influenzae and the Effect of PIN Domain Mutations on Survival during Infection. J Bacteriol 2019; 201:JB.00026-19. [PMID: 30936373 DOI: 10.1128/jb.00026-19] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 03/29/2019] [Indexed: 12/15/2022] Open
Abstract
Toxin-antitoxin (TA) gene pairs have been identified in nearly all bacterial genomes sequenced to date and are thought to facilitate persistence and antibiotic tolerance. TA loci are classified into various types based upon the characteristics of their antitoxins, with those in type II expressing proteic antitoxins. Many toxins from type II modules are ribonucleases that maintain a PilT N-terminal (PIN) domain containing conserved amino acids considered essential for activity. The vapBC (virulence-associated protein) TA system is the largest subfamily in this class and has been linked to pathogenesis of nontypeable Haemophilus influenzae (NTHi). In this study, the crystal structure of the VapBC-1 complex from NTHi was determined to 2.20 Å resolution. Based on this structure, aspartate-to-asparagine and glutamate-to-glutamine mutations of four conserved residues in the PIN domain of the VapC-1 toxin were constructed and the effects of the mutations on protein-protein interactions, growth of Escherichia coli, and pathogenesis ex vivo were tested. Finally, a novel model system was designed and utilized that consists of an NTHi ΔvapBC-1 strain complemented in cis with the TA module containing a mutated or wild-type toxin at an ectopic site on the chromosome. This enabled the analysis of the effect of PIN domain toxin mutants in tandem with their wild-type antitoxin under the control of the vapBC-1 native promoter and in single copy. This is the first report of a system facilitating the study of TA mutant operons in the background of NTHi during infections of primary human tissues ex vivo IMPORTANCE Herein the crystal structure of the VapBC-1 complex from nontypeable Haemophilus influenzae (NTHi) is described. Our results show that some of the mutations in the PIN domain of the VapC-1 toxin were associated with decreased toxicity in E. coli, but the mutants retained the ability to homodimerize and to heterodimerize with the wild-type cognate antitoxin, VapB-1. A new system was designed and constructed to quantify the effects of these mutations on NTHi survival during infections of primary human tissues ex vivo Any mutation to a conserved amino acid in the PIN domain significantly decreased the number of survivors compared to that of the in cis wild-type toxin under the same conditions.
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5
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Vandervelde A, Drobnak I, Hadži S, Sterckx YGJ, Welte T, De Greve H, Charlier D, Efremov R, Loris R, Lah J. Molecular mechanism governing ratio-dependent transcription regulation in the ccdAB operon. Nucleic Acids Res 2017; 45:2937-2950. [PMID: 28334797 PMCID: PMC5389731 DOI: 10.1093/nar/gkx108] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Revised: 01/25/2017] [Accepted: 02/06/2017] [Indexed: 02/06/2023] Open
Abstract
Bacteria can become transiently tolerant to several classes of antibiotics. This phenomenon known as persistence is regulated by small genetic elements called toxin-antitoxin modules with intricate yet often poorly understood self-regulatory features. Here, we describe the structures of molecular complexes and interactions that drive the transcription regulation of the ccdAB toxin-antitoxin module. Low specificity and affinity of the antitoxin CcdA2 for individual binding sites on the operator are enhanced by the toxin CcdB2, which bridges the CcdA2 dimers. This results in a unique extended repressing complex that spirals around the operator and presents equally spaced DNA binding sites. The multivalency of binding sites induces a digital on-off switch for transcription, regulated by the toxin:antitoxin ratio. The ratio at which this switch occurs is modulated by non-specific interactions with the excess chromosomal DNA. Altogether, we present the molecular mechanisms underlying the ratio-dependent transcriptional regulation of the ccdAB operon.
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Affiliation(s)
- Alexandra Vandervelde
- Structural Biology Brussels, Department of Bioengineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussel, Belgium
- Center for Structural Biology, Vlaams Instituut voor Biotechnologie, B-1050 Brussel, Belgium
| | - Igor Drobnak
- Department of Physical Chemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, 1000 Ljubljana, Slovenia
| | - San Hadži
- Structural Biology Brussels, Department of Bioengineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussel, Belgium
- Center for Structural Biology, Vlaams Instituut voor Biotechnologie, B-1050 Brussel, Belgium
- Department of Physical Chemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, 1000 Ljubljana, Slovenia
| | - Yann G.-J. Sterckx
- Center for Structural Biology, Vlaams Instituut voor Biotechnologie, B-1050 Brussel, Belgium
- Research Unit for Cellular and Molecular Immunology (CMIM), VUB, Pleinlaan 2, B-1050 Brussel, Belgium
| | - Thomas Welte
- Dynamic Biosensors GmbH, Lochhamer Strasse 15, D-82152 Martinsried, Germany
| | - Henri De Greve
- Structural Biology Brussels, Department of Bioengineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussel, Belgium
- Center for Structural Biology, Vlaams Instituut voor Biotechnologie, B-1050 Brussel, Belgium
| | - Daniel Charlier
- Research Group of Microbiology, Department of Bioengineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussel, Belgium
| | - Rouslan Efremov
- Structural Biology Brussels, Department of Bioengineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussel, Belgium
- Center for Structural Biology, Vlaams Instituut voor Biotechnologie, B-1050 Brussel, Belgium
| | - Remy Loris
- Structural Biology Brussels, Department of Bioengineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussel, Belgium
- Center for Structural Biology, Vlaams Instituut voor Biotechnologie, B-1050 Brussel, Belgium
| | - Jurij Lah
- Department of Physical Chemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, 1000 Ljubljana, Slovenia
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Structure, Biology, and Therapeutic Application of Toxin-Antitoxin Systems in Pathogenic Bacteria. Toxins (Basel) 2016; 8:toxins8100305. [PMID: 27782085 PMCID: PMC5086665 DOI: 10.3390/toxins8100305] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 10/17/2016] [Accepted: 10/18/2016] [Indexed: 01/09/2023] Open
Abstract
Bacterial toxin–antitoxin (TA) systems have received increasing attention for their diverse identities, structures, and functional implications in cell cycle arrest and survival against environmental stresses such as nutrient deficiency, antibiotic treatments, and immune system attacks. In this review, we describe the biological functions and the auto-regulatory mechanisms of six different types of TA systems, among which the type II TA system has been most extensively studied. The functions of type II toxins include mRNA/tRNA cleavage, gyrase/ribosome poison, and protein phosphorylation, which can be neutralized by their cognate antitoxins. We mainly explore the similar but divergent structures of type II TA proteins from 12 important pathogenic bacteria, including various aspects of protein–protein interactions. Accumulating knowledge about the structure–function correlation of TA systems from pathogenic bacteria has facilitated a novel strategy to develop antibiotic drugs that target specific pathogens. These molecules could increase the intrinsic activity of the toxin by artificially interfering with the intermolecular network of the TA systems.
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7
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Zaychikova MV, Zakharevich NV, Sagaidak MO, Bogolubova NA, Smirnova TG, Andreevskaya SN, Larionova EE, Alekseeva MG, Chernousova LN, Danilenko VN. Mycobacterium tuberculosis Type II Toxin-Antitoxin Systems: Genetic Polymorphisms and Functional Properties and the Possibility of Their Use for Genotyping. PLoS One 2015; 10:e0143682. [PMID: 26658274 PMCID: PMC4680722 DOI: 10.1371/journal.pone.0143682] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 11/08/2015] [Indexed: 12/05/2022] Open
Abstract
Various genetic markers such as IS-elements, DR-elements, variable number tandem repeats (VNTR), single nucleotide polymorphisms (SNPs) in housekeeping genes and other groups of genes are being used for genotyping. We propose a different approach. We suggest the type II toxin-antitoxin (TA) systems, which play a significant role in the formation of pathogenicity, tolerance and persistence phenotypes, and thus in the survival of Mycobacterium tuberculosis in the host organism at various developmental stages (colonization, infection of macrophages, etc.), as the marker genes. Most genes of TA systems function together, forming a single network: an antitoxin from one pair may interact with toxins from other pairs and even from other families. In this work a bioinformatics analysis of genes of the type II TA systems from 173 sequenced genomes of M. tuberculosis was performed. A number of genes of type II TA systems were found to carry SNPs that correlate with specific genotypes. We propose a minimally sufficient set of genes of TA systems for separation of M. tuberculosis strains at nine basic genotype and for further division into subtypes. Using this set of genes, we genotyped a collection consisting of 62 clinical isolates of M. tuberculosis. The possibility of using our set of genes for genotyping using PCR is also demonstrated.
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Affiliation(s)
- Marina V. Zaychikova
- Vavilov Institute of General Genetics, Russian Academy of Sciences, Moscow, Russia
- Scientific Research Center for Biotechnology of Antibiotics "BIOAN", Moscow, Russia
| | | | - Maria O. Sagaidak
- Vavilov Institute of General Genetics, Russian Academy of Sciences, Moscow, Russia
- State University, Moscow Institute of Physics and Technology, Moscow, Russia
| | | | | | | | | | - Maria G. Alekseeva
- Vavilov Institute of General Genetics, Russian Academy of Sciences, Moscow, Russia
| | | | - Valery N. Danilenko
- Vavilov Institute of General Genetics, Russian Academy of Sciences, Moscow, Russia
- Scientific Research Center for Biotechnology of Antibiotics "BIOAN", Moscow, Russia
- * E-mail:
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8
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Demidenok OI, Goncharenko AV. Bacterial toxin-antitoxin systems and perspectives for their application in medicine. APPL BIOCHEM MICRO+ 2013. [DOI: 10.1134/s0003683813060070] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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9
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Mruk I, Kobayashi I. To be or not to be: regulation of restriction-modification systems and other toxin-antitoxin systems. Nucleic Acids Res 2013; 42:70-86. [PMID: 23945938 PMCID: PMC3874152 DOI: 10.1093/nar/gkt711] [Citation(s) in RCA: 164] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
One of the simplest classes of genes involved in programmed death is that containing the toxin–antitoxin (TA) systems of prokaryotes. These systems are composed of an intracellular toxin and an antitoxin that neutralizes its effect. These systems, now classified into five types, were initially discovered because some of them allow the stable maintenance of mobile genetic elements in a microbial population through postsegregational killing or the death of cells that have lost these systems. Here, we demonstrate parallels between some TA systems and restriction–modification systems (RM systems). RM systems are composed of a restriction enzyme (toxin) and a modification enzyme (antitoxin) and limit the genetic flux between lineages with different epigenetic identities, as defined by sequence-specific DNA methylation. The similarities between these systems include their postsegregational killing and their effects on global gene expression. Both require the finely regulated expression of a toxin and antitoxin. The antitoxin (modification enzyme) or linked protein may act as a transcriptional regulator. A regulatory antisense RNA recently identified in an RM system can be compared with those RNAs in TA systems. This review is intended to generalize the concept of TA systems in studies of stress responses, programmed death, genetic conflict and epigenetics.
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Affiliation(s)
- Iwona Mruk
- Department of Microbiology, University of Gdansk, Wita Stwosza 59, Gdansk, 80-308, Poland, Department of Medical Genome Sciences, Graduate School of Frontier Sciences, University of Tokyo, Tokyo 108-8639, Japan and Institute of Medical Science, University of Tokyo, Tokyo 108-8639, Japan
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10
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Drobnak I, De Jonge N, Haesaerts S, Vesnaver G, Loris R, Lah J. Energetic Basis of Uncoupling Folding from Binding for an Intrinsically Disordered Protein. J Am Chem Soc 2013; 135:1288-94. [DOI: 10.1021/ja305081b] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Igor Drobnak
- Department of Physical Chemistry,
Faculty of Chemistry and Chemical Technology, University of Ljubljana, Askerceva 5, 1000 Ljubljana, Slovenia
| | - Natalie De Jonge
- Molecular Recognition Unit,
Department of Structural Biology, VIB,
Pleinlaan 2, B-1050 Brussel, Belgium
- Structural Biology Brussels, Department
of Biotechnology, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussel, Belgium
| | - Sarah Haesaerts
- Molecular Recognition Unit,
Department of Structural Biology, VIB,
Pleinlaan 2, B-1050 Brussel, Belgium
- Structural Biology Brussels, Department
of Biotechnology, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussel, Belgium
| | - Gorazd Vesnaver
- Department of Physical Chemistry,
Faculty of Chemistry and Chemical Technology, University of Ljubljana, Askerceva 5, 1000 Ljubljana, Slovenia
| | - Remy Loris
- Molecular Recognition Unit,
Department of Structural Biology, VIB,
Pleinlaan 2, B-1050 Brussel, Belgium
- Structural Biology Brussels, Department
of Biotechnology, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussel, Belgium
| | - Jurij Lah
- Department of Physical Chemistry,
Faculty of Chemistry and Chemical Technology, University of Ljubljana, Askerceva 5, 1000 Ljubljana, Slovenia
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11
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Kim KS, Lee JY, Kwon SY, Yang HJ, Choi EK, Shin MH, Ahn KS, Um JY, Lee JH, Jang HJ. Comparative transcriptomic analysis of the multi-targeted effects of the herbal extracts against Escherichia coli O157:H7. BIOCHIP JOURNAL 2012. [DOI: 10.1007/s13206-012-6410-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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12
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Kim KS, Lim DJ, Yang HJ, Choi EK, Shin MH, Ahn KS, Jung SH, Um JY, Jung HJ, Lee JH, Lee SG, Jung SK, Jang HJ. The multi-targeted effects of Chrysanthemum herb extract against Escherichia coli O157:H7. Phytother Res 2012; 27:1398-406. [PMID: 23255247 DOI: 10.1002/ptr.4859] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2012] [Revised: 09/04/2012] [Accepted: 09/20/2012] [Indexed: 01/15/2023]
Abstract
The Chrysanthemum lavandulifolium extract, which includes chrysoeriol, sudachitin, and acacetin, has excellent antibiotic effects on Escherichia coli O157:H7 (E. coli O157). A notable point is that the antibiotic targets of the herb extract are similar to the targets of commonly used antibiotic drugs, including bacterial cell wall biosynthesis, bacterial protein synthesis, and bacterial DNA replication and repair. In addition, the herbal antibiotic inhibits the etiological factors that contribute to the pathogenic property. The herbal sample was extracted and fractionated and then inoculated through a disk diffusion method to confirm its antibiotic effect against E. coli O157. Total RNA was isolated from the affected bacterial cells, and its expression level was analyzed through a microarray analysis. To confirm the accuracy of the microarray data, a real-time PCR was performed. Three active compounds, chrysoeriol, sudachitin, and acacetin, were identified with a high-performance liquid chromatography-electrospray ionization/mass spectrometry chromatogram, and the disk diffusion study confirmed that chrysoeriol and sudachitin contribute to the antibiotic properties of the herb extract. The results demonstrate that the multi-target efficacy of the herbal sample may indicate the potential for the development of more effective and safer drugs that will act as substitutes for existing antibiotics.
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Affiliation(s)
- Ki-Suk Kim
- College of Oriental Medicine, Institute of Oriental Medicine, Kyung Hee University, Heogi-dong, Dongdaemun-gu, Seoul 130-701, Republic of Korea
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13
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De Jonge N, Simic M, Buts L, Haesaerts S, Roelants K, Garcia-Pino A, Sterckx Y, De Greve H, Lah J, Loris R. Alternative interactions define gyrase specificity in the CcdB family. Mol Microbiol 2012; 84:965-78. [DOI: 10.1111/j.1365-2958.2012.08069.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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14
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Marušič J, Podlipnik Č, Jevševar S, Kuzman D, Vesnaver G, Lah J. Recognition of human tumor necrosis factor α (TNF-α) by therapeutic antibody fragment: energetics and structural features. J Biol Chem 2012; 287:8613-20. [PMID: 22262846 DOI: 10.1074/jbc.m111.318451] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Human tumor necrosis factor α (TNF-α) exists in its functional state as a homotrimeric protein and is involved in inflammation processes and immune response of a human organism. Overproduction of TNF-α results in the development of chronic autoimmune diseases that can be successfully treated by inhibitors such as monoclonal antibodies. However, the nature of antibody-TNF-α recognition remains elusive due to insufficient understanding of its molecular driving forces. Therefore, we studied the energetics of binding of a therapeutic antibody fragment (Fab) to the native and non-native forms of TNF-α by employing calorimetric and spectroscopic methods. Global thermodynamic analysis of data obtained from the corresponding binding and urea-induced denaturation experiments has been supported by structural modeling. We demonstrate that the observed high affinity binding of Fab to TNF-α is an enthalpy-driven process due mainly to specific noncovalent interactions taking place at the TNF-α-Fab binding interface. It is coupled to entropically unfavorable conformational changes and accompanied by entropically favorable solvation contributions. Moreover, the three-state model analysis of TNF-α unfolding shows that at physiological concentrations, TNF-α may exist not only as a biologically active trimer but also as an inactive monomer. It further suggests that even small changes of TNF-α concentration could have a considerable effect on the TNF-α activity. We believe that this study sets the energetic basis for understanding of TNF-α inhibition by antibodies and its unfolding linked with the concentration-dependent activity regulation.
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Affiliation(s)
- Jaka Marušič
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Aškerčeva 5, 1000 Ljubljana, Slovenia
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15
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Hayes F, Van Melderen L. Toxins-antitoxins: diversity, evolution and function. Crit Rev Biochem Mol Biol 2011; 46:386-408. [PMID: 21819231 DOI: 10.3109/10409238.2011.600437] [Citation(s) in RCA: 196] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Genes for toxin-antitoxin (TA) complexes are widespread in prokaryote genomes, and species frequently possess tens of plasmid and chromosomal TA loci. The complexes are categorized into three types based on genetic organization and mode of action. The toxins universally are proteins directed against specific intracellular targets, whereas the antitoxins are either proteins or small RNAs that neutralize the toxin or inhibit toxin synthesis. Within the three types of complex, there has been extensive evolutionary shuffling of toxin and antitoxin genes leading to considerable diversity in TA combinations. The intracellular targets of the protein toxins similarly are varied. Numerous toxins, many of which are sequence-specific endoribonucleases, dampen protein synthesis levels in response to a range of stress and nutritional stimuli. Key resources are conserved as a result ensuring the survival of individual cells and therefore the bacterial population. The toxin effects generally are transient and reversible permitting a set of dynamic, tunable responses that reflect environmental conditions. Moreover, by harboring multiple toxins that intercede in protein synthesis in response to different physiological cues, bacteria potentially sense an assortment of metabolic perturbations that are channeled through different TA complexes. Other toxins interfere with the action of topoisomersases, cell wall assembly, or cytoskeletal structures. TAs also play important roles in bacterial persistence, biofilm formation and multidrug tolerance, and have considerable potential both as new components of the genetic toolbox and as targets for novel antibacterial drugs.
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Affiliation(s)
- Finbarr Hayes
- Faculty of Life Sciences and Manchester Interdisciplinary Biocentre, The University of Manchester, Manchester, UK.
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16
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Andjelković U, Lah J. Thermodynamics and structural features of the yeast Saccharomyces cerevisiae external invertase isoforms in guanidinium-chloride solutions. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2011; 59:727-732. [PMID: 21182261 DOI: 10.1021/jf103441p] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Recently, four external invertase isoforms (EINV1, EINV2, EINV3, and EINV4) have been isolated from S. cerevisiae. However, there is nothing known about their structural features and thermodynamics of unfolding. Since this information is essential for understanding their functioning at the molecular level as well as applicable in the food industry, we investigated guanidinium-chloride induced structural changes of the isoforms by CD and fluorescence spectroscopy. The resulting unfolding curves measured for each isoform at different temperatures were described simultaneously by a reversible two-state model to obtain the corresponding thermodynamic parameters. Here, we show that they are different for different isoforms and demonstrate that they correlate with the surface charge density of the native isoforms which follows the order EINV1 < EINV2 < EINV3 < EINV4. It appears that at physiological temperatures the thermodynamic stability of the isoforms follows the same order, while above 55 °C, the order is the opposite EINV1 > EINV2 > EINV3 ≈ EINV4. This suggests that increasing the efficiency of the food industry processes involving invertase would require the application of EINV3 and/or EINV4 at physiological temperatures and EINV1 at elevated temperatures.
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Affiliation(s)
- Uros Andjelković
- Department of Chemistry, Institute for Chemistry, Technology and Metallurgy, University of Belgrade, Studentski trg 12-16, 11000 Belgrade, Serbia
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17
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Falconer RJ, Collins BM. Survey of the year 2009: applications of isothermal titration calorimetry. J Mol Recognit 2010; 24:1-16. [DOI: 10.1002/jmr.1073] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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18
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Yuan J, Sterckx Y, Mitchenall LA, Maxwell A, Loris R, Waldor MK. Vibrio cholerae ParE2 poisons DNA gyrase via a mechanism distinct from other gyrase inhibitors. J Biol Chem 2010; 285:40397-408. [PMID: 20952390 PMCID: PMC3001019 DOI: 10.1074/jbc.m110.138776] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
DNA gyrase is an essential bacterial enzyme required for the maintenance of chromosomal DNA topology. This enzyme is the target of several protein toxins encoded in toxin-antitoxin (TA) loci as well as of man-made antibiotics such as quinolones. The genome of Vibrio cholerae, the cause of cholera, contains three putative TA loci that exhibit modest similarity to the RK2 plasmid-borne parDE TA locus, which is thought to target gyrase although its mechanism of action is uncharacterized. Here we investigated the V. cholerae parDE2 locus. We found that this locus encodes a functional proteic TA pair that is active in Escherichia coli as well as V. cholerae. ParD2 co-purified with ParE2 and interacted with it directly. Unlike many other antitoxins, ParD2 could prevent but not reverse ParE2 toxicity. ParE2, like the unrelated F-encoded toxin CcdB and quinolones, targeted the GyrA subunit and stalled the DNA-gyrase cleavage complex. However, in contrast to other gyrase poisons, ParE2 toxicity required ATP, and it interfered with gyrase-dependent DNA supercoiling but not DNA relaxation. ParE2 did not bind GyrA fragments bound by CcdB and quinolones, and a set of strains resistant to a variety of known gyrase inhibitors all exhibited sensitivity to ParE2. Together, our findings suggest that ParE2 and presumably its many plasmid- and chromosome-encoded homologues inhibit gyrase in a different manner than previously described agents.
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Affiliation(s)
- Jie Yuan
- Channing Laboratory, Brigham and Women's Hospital, Harvard Medical School, Tufts University School of Medicine, Boston, Massachusetts 02115, USA
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Diago-Navarro E, Hernandez-Arriaga AM, López-Villarejo J, Muñoz-Gómez AJ, Kamphuis MB, Boelens R, Lemonnier M, Díaz-Orejas R. parD toxin-antitoxin system of plasmid R1 - basic contributions, biotechnological applications and relationships with closely-related toxin-antitoxin systems. FEBS J 2010; 277:3097-117. [DOI: 10.1111/j.1742-4658.2010.07722.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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20
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Sissi C, Palumbo M. In front of and behind the replication fork: bacterial type IIA topoisomerases. Cell Mol Life Sci 2010; 67:2001-24. [PMID: 20165898 PMCID: PMC11115839 DOI: 10.1007/s00018-010-0299-5] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2009] [Revised: 01/26/2010] [Accepted: 02/01/2010] [Indexed: 01/03/2023]
Abstract
Topoisomerases are vital enzymes specialized in controlling DNA topology, in particular supercoiling and decatenation, to properly handle nucleic acid packing and cell dynamics. The type IIA enzymes act by cleaving both strands of a double helix and having another strand from the same or another molecule cross the DNA gate before a re-sealing event completes the catalytic cycle. Here, we will consider the two types of IIA prokaryotic topoisomerases, DNA Gyrase and Topoisomerase IV, as crucial regulators of bacterial cell cycle progression. Their synergistic action allows control of chromosome packing and grants occurrence of functional transcription and replication processes. In addition to displaying a fascinating molecular mechanism of action, which transduces chemical energy into mechanical energy by means of large conformational changes, these enzymes represent attractive pharmacological targets for antibacterial chemotherapy.
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Affiliation(s)
- Claudia Sissi
- Department of Pharmaceutical Sciences, University of Padova, Via Marzolo 5, 35131, Padua, Italy.
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De Jonge N, Hohlweg W, Garcia-Pino A, Respondek M, Buts L, Haesaerts S, Lah J, Zangger K, Loris R. Structural and thermodynamic characterization of Vibrio fischeri CcdB. J Biol Chem 2010; 285:5606-13. [PMID: 19959472 PMCID: PMC2820787 DOI: 10.1074/jbc.m109.068429] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2009] [Revised: 10/31/2009] [Indexed: 11/06/2022] Open
Abstract
CcdB(Vfi) from Vibrio fischeri is a member of the CcdB family of toxins that poison covalent gyrase-DNA complexes. In solution CcdB(Vfi) is a dimer that unfolds to the corresponding monomeric components in a two-state fashion. In the unfolded state, the monomer retains a partial secondary structure. This observation correlates well with the crystal and NMR structures of the protein, which show a dimer with a hydrophobic core crossing the dimer interface. In contrast to its F plasmid homologue, CcdB(Vfi) possesses a rigid dimer interface, and the apparent relative rotations of the two subunits are due to structural plasticity of the monomer. CcdB(Vfi) shows a number of non-conservative substitutions compared with the F plasmid protein in both the CcdA and the gyrase binding sites. Although variation in the CcdA interaction site likely determines toxin-antitoxin specificity, substitutions in the gyrase-interacting region may have more profound functional implications.
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Affiliation(s)
- Natalie De Jonge
- From Structural Biology Brussels and
- the Department of Molecular and Cellular Interactions, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium
| | - Walter Hohlweg
- the Institute of Chemistry, University of Graz, Heinrichstrasse 28, 8010 Graz, Austria, and
| | - Abel Garcia-Pino
- From Structural Biology Brussels and
- the Department of Molecular and Cellular Interactions, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium
| | - Michal Respondek
- the Institute of Chemistry, University of Graz, Heinrichstrasse 28, 8010 Graz, Austria, and
| | - Lieven Buts
- From Structural Biology Brussels and
- the Department of Molecular and Cellular Interactions, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium
| | - Sarah Haesaerts
- From Structural Biology Brussels and
- the Department of Molecular and Cellular Interactions, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium
| | - Jurij Lah
- the Faculty of Chemistry and Chemical Technology, University of Ljubljana, Askerceva 5, 1000 Ljubljana, Slovenia
| | - Klaus Zangger
- the Institute of Chemistry, University of Graz, Heinrichstrasse 28, 8010 Graz, Austria, and
| | - Remy Loris
- From Structural Biology Brussels and
- the Department of Molecular and Cellular Interactions, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium
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