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Herlah B, Pavlin M, Perdih A. Molecular choreography: Unveiling the dynamic landscape of type IIA DNA topoisomerases before T-segment passage through all-atom simulations. Int J Biol Macromol 2024:131991. [PMID: 38714283 DOI: 10.1016/j.ijbiomac.2024.131991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Revised: 04/09/2024] [Accepted: 04/28/2024] [Indexed: 05/09/2024]
Abstract
Type IIA DNA topoisomerases are molecular nanomachines responsible for controlling topological states of DNA molecules. Here, we explore the dynamic landscape of yeast topoisomerase IIA during key stages of its catalytic cycle, focusing in particular on the events preceding the passage of the T-segment. To this end, we generated six configurations of fully catalytic yeast topo IIA, strategically inserted a T-segment into the N-gate in relevant configurations and performed all-atom simulations. The essential motion of topo IIA protein dimer was characterized by rotational gyrating-like movement together with sliding motion within the DNA-gate. Both appear to be inherent properties of the enzyme and an inbuilt feature that allows passage of the T-segment through the cleaved G-segment. Coupled dynamics of the N-gate and DNA-gate residues may be particularly important for controlled and smooth passage of the T-segment and consequently the prevention of DNA double-strand breaks. QTK loop residue Lys367, which interacts with ATP and ADP molecules, is involved in regulating the size and stability of the N-gate. The unveiled features of the simulated configurations provide insights into the catalytic cycle of type IIA topoisomerases and elucidate the molecular choreography governing their ability to modulate the topological states of DNA topology.
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Affiliation(s)
- Barbara Herlah
- Theory Department, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia; University of Ljubljana, Faculty of Pharmacy, Aškerčeva 7, 1000 Ljubljana, Slovenia
| | - Matic Pavlin
- Department of Catalysis and Chemical Reaction Engineering, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
| | - Andrej Perdih
- Theory Department, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia; University of Ljubljana, Faculty of Pharmacy, Aškerčeva 7, 1000 Ljubljana, Slovenia.
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Pavlin M, Herlah B, Valjavec K, Perdih A. Unveiling the interdomain dynamics of type II DNA topoisomerase through all-atom simulations: Implications for understanding its catalytic cycle. Comput Struct Biotechnol J 2023; 21:3746-3759. [PMID: 37602233 PMCID: PMC10436251 DOI: 10.1016/j.csbj.2023.07.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2023] [Revised: 07/01/2023] [Accepted: 07/19/2023] [Indexed: 08/22/2023] Open
Abstract
Type IIA DNA topoisomerases are complex molecular nanomachines that manage topological states of the DNA molecule in the cell and play a crucial role in cellular processes such as cell division and transcription. They are also established targets of cancer chemotherapy. Starting from the available crystal structure of a fully catalytic topoisomerase IIA homodimer from Saccharomyces cerevisiae, we constructed three states of this molecular motor primarily changing the configurations of the DNA segment bound in the DNA gate and performed μs-long all-atom molecular simulations. A comprehensive analysis revealed a sliding motion within the DNA gate and a teamwork between the N-gate and DNA gate that may be associated with the necessary molecular events that allow passage of the T-segment of DNA. The observed movement of the ATPase dimer relative to the DNA domain was reflected in different interaction patterns between the K-loops of the transducer domain and the B-A-B form of the bound DNA. Based on the obtained results, we mapped simulated configurations to the structures in the proposed catalytic cycle through which type IIA topoisomerases exert their function and discussed the possible transition events. The results extend our understanding of the mechanism of action of type IIA topoisomerases and provide an atomistic interpretation of some of the observed features of these molecular motors.
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Affiliation(s)
- Matic Pavlin
- Department of Catalysis and Chemical Reaction Engineering, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
| | - Barbara Herlah
- Theory Department, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
- University of Ljubljana, Faculty of Pharmacy, Aškerčeva 7, 1000 Ljubljana, Slovenia
| | - Katja Valjavec
- Theory Department, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
| | - Andrej Perdih
- Theory Department, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
- University of Ljubljana, Faculty of Pharmacy, Aškerčeva 7, 1000 Ljubljana, Slovenia
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Lenin B, Ramasubramanyan S, Vetrivel U, Chitipothu S. Virtual screening and multilevel precision-based prioritisation of natural inhibitors targeting the ATPase domain of human DNA topoisomerase II alpha. J Biomol Struct Dyn 2023; 41:15177-15195. [PMID: 36898858 DOI: 10.1080/07391102.2023.2187234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 02/25/2023] [Indexed: 03/12/2023]
Abstract
Human DNA topoisomerase II alpha (hTopIIα) is a classic chemotherapeutic drug target. The existing hTopIIα poisons cause numerous side effects such as the development of cardiotoxicity, secondary malignancies, and multidrug resistance. The use of catalytic inhibitors targeting the ATP-binding cavity of the enzyme is considered a safer alternative due to the less deleterious mechanism of action. Hence, in this study, we carried out high throughput structure-based virtual screening of the NPASS natural product database against the ATPase domain of hTopIIα and identified the five best ligand hits. This was followed by comprehensive validation through molecular dynamics simulations, binding free energy calculation and ADMET analysis. On stringent multilevel prioritization, we identified promising natural product catalytic inhibitors that showed high binding affinity and stability within the ligand-binding cavity and may serve as ideal hits for anticancer drug development.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Barathi Lenin
- Centre for Bioinformatics, Kamalnayan Bajaj Institute for Research in Vision and Ophthalmology, Vision Research Foundation, Chennai, Tamil Nadu, India
| | - Sharada Ramasubramanyan
- RS Mehta Jain Department of Biochemistry and Cell Biology, Kamalnayan Bajaj Institute for Research in Vision and Ophthalmology, Vision Research Foundation, Chennai, Tamil Nadu, India
| | - Umashankar Vetrivel
- Centre for Bioinformatics, Kamalnayan Bajaj Institute for Research in Vision and Ophthalmology, Vision Research Foundation, Chennai, Tamil Nadu, India
- National Institute of Traditional Medicine, Indian Council of Medical Research, Belagavi, Karnataka, India
| | - Srujana Chitipothu
- Centre for Bioinformatics, Kamalnayan Bajaj Institute for Research in Vision and Ophthalmology, Vision Research Foundation, Chennai, Tamil Nadu, India
- Central Research Instrumentation Facility, Kamalnayan Bajaj Institute for Research in Vision and Ophthalmology, Vision Research Foundation, Chennai, Tamil Nadu, India
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Ogrizek M, Janežič M, Valjavec K, Perdih A. Catalytic Mechanism of ATP Hydrolysis in the ATPase Domain of Human DNA Topoisomerase IIα. J Chem Inf Model 2022; 62:3896-3909. [PMID: 35948041 PMCID: PMC9400105 DOI: 10.1021/acs.jcim.2c00303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
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Human DNA topoisomerase IIα is a biological nanomachine
that
regulates the topological changes of the DNA molecule and is considered
a prime target for anticancer drugs. Despite intensive research, many
atomic details about its mechanism of action remain unknown. We investigated
the ATPase domain, a segment of the human DNA topoisomerase IIα,
using all-atom molecular simulations, multiscale quantum mechanics/molecular
mechanics (QM/MM) calculations, and a point mutation study. The results
suggested that the binding of ATP affects the overall dynamics of
the ATPase dimer. Reaction modeling revealed that ATP hydrolysis favors
the dissociative substrate-assisted reaction mechanism with the catalytic
Glu87 serving to properly position and polarize the lytic water molecule.
The point mutation study complemented our computational results, demonstrating
that Lys378, part of the important QTK loop, acts as a stabilizing
residue. The work aims to pave the way to a deeper understanding of
these important molecular motors and to advance the development of
new therapeutics.
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Affiliation(s)
- Mitja Ogrizek
- National Institute of Chemistry, Hajdrihova 19, SI-1001 Ljubljana, Slovenia
| | - Matej Janežič
- National Institute of Chemistry, Hajdrihova 19, SI-1001 Ljubljana, Slovenia
| | - Katja Valjavec
- National Institute of Chemistry, Hajdrihova 19, SI-1001 Ljubljana, Slovenia
| | - Andrej Perdih
- National Institute of Chemistry, Hajdrihova 19, SI-1001 Ljubljana, Slovenia.,Faculty of Pharmacy, University of Ljubljana, Aškerčeva 7, SI 1000 Ljubljana, Slovenia
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Dutta S, Kundu S, Saha A, Nandi N. Dynamics of the active site loops in catalyzing aminoacylation reaction in seryl and histidyl tRNA synthetases. J Biomol Struct Dyn 2017; 36:878-892. [PMID: 28317434 DOI: 10.1080/07391102.2017.1301272] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Aminoacylation reaction is the first step of protein biosynthesis. The catalytic reorganization at the active site of aminoacyl tRNA synthetases (aaRSs) is driven by the loop motions. There remain lacunae of understanding concerning the catalytic loop dynamics in aaRSs. We analyzed the functional loop dynamics in seryl tRNA synthetase from Methanopyrus kandleri (mkSerRS) and histidyl tRNA synthetases from Thermus thermophilus (ttHisRS), respectively, using molecular dynamics. Results confirm that the motif 2 loop and other active site loops are flexible spots within the catalytic domain. Catalytic residues of the loops form a network of interaction with the substrates to form a reactive state. The loops undergo transitions between closed state and open state and the relaxation of the constituent residues occurs in femtosecond to nanosecond time scale. Order parameters are higher for constituent catalytic residues which form a specific network of interaction with the substrates to form a reactive state compared to the Gly residues within the loop. The development of interaction is supported from mutation studies where the catalytic domain with mutated loop exhibits unfavorable binding energy with the substrates. During the open-close motion of the loops, the catalytic residues make relaxation by ultrafast librational motion as well as fast diffusive motion and subsequently relax rather slowly via slower diffusive motion. The Gly residues act as a hinge to facilitate the loop closing and opening by their faster relaxation behavior. The role of bound water is analyzed by comparing implicit solvent-based and explicit solvent-based simulations. Loops fail to form catalytically competent geometry in absence of water. The present result, for the first time reveals the nature of the active site loop dynamics in aaRS and their influence on catalysis.
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Affiliation(s)
- Saheb Dutta
- a Department of Chemistry , University of Kalyani , Kalyani , 741235 , India
| | - Soumya Kundu
- a Department of Chemistry , University of Kalyani , Kalyani , 741235 , India
| | - Amrita Saha
- a Department of Chemistry , University of Kalyani , Kalyani , 741235 , India
| | - Nilashis Nandi
- a Department of Chemistry , University of Kalyani , Kalyani , 741235 , India
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Affiliation(s)
- Saheb Dutta
- Department
of Chemistry, University of Kalyani, Kalyani, Nadia, West Bengal 741235, India
| | - Nilashis Nandi
- Department
of Chemistry, University of Kalyani, Kalyani, Nadia, West Bengal 741235, India
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Pogorelčnik B, Brvar M, Žegura B, Filipič M, Solmajer T, Perdih A. Discovery of Mono- and Disubstituted 1H-Pyrazolo[3,4]pyrimidines and 9H-Purines as Catalytic Inhibitors of Human DNA Topoisomerase IIα. ChemMedChem 2014; 10:345-59. [DOI: 10.1002/cmdc.201402459] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Indexed: 11/07/2022]
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Abstract
Topoisomerases are essential enzymes that are involved in DNA metabolism. Topoisomerase II generates transient DNA strand breaks that are stabilized by anticancer drugs, such as doxorubicin, causing an accumulation of DNA damage. However, doxorubicin causes cardiac toxicity and, like etoposide and other topoisomerase II-targeted agents, can induce DNA damage, resulting in secondary cancers. The cannabinoid quinone HU-331 has been identified as a potential anticancer drug that demonstrates more potency in cancer cells with less off-target toxicity than that of doxorubicin. Reports indicate that HU-331 does not promote cell death via apoptosis, cell cycle arrest, caspase activation, or DNA strand breaks. However, the precise mechanism of action is poorly understood. We employed biochemical assays to study the mechanism of action of HU-331 against purified topoisomerase IIα. These assays examined DNA binding, cleavage, ligation, relaxation, and ATPase activities of topoisomerase IIα. Our results demonstrate that HU-331 inhibits topoisomerase IIα-mediated DNA relaxation at micromolar levels. We find that HU-331 does not induce DNA strand breaks in vitro. When added prior to the DNA substrate, HU-331 blocks DNA cleavage and relaxation activities of topoisomerase IIα in a redox-sensitive manner. The action of HU-331 can be blocked, but not reversed, by the presence of dithiothreitol. Our results also show that HU-331 inhibits the ATPase activity of topoisomerase IIα using a noncompetitive mechanism. Preliminary binding studies also indicate that HU-331 decreases the ability of topoisomerase IIα to bind DNA. In summary, HU-331 inhibits relaxation activity without poisoning DNA cleavage. This action is sensitive to reducing agents and appears to involve noncompetitive inhibition of the ATPase activity and possibly inhibition of DNA binding. These studies provide a promising foundation for the exploration of HU-331 as a catalytic inhibitor of topoisomerase IIα.
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Affiliation(s)
- Kellie M Regal
- Department of Pharmaceutical Sciences, Lipscomb University College of Pharmacy and Health Sciences , Nashville, Tennessee 37204-3951, United States
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Stanger FV, Dehio C, Schirmer T. Structure of the N-terminal Gyrase B fragment in complex with ADP⋅Pi reveals rigid-body motion induced by ATP hydrolysis. PLoS One 2014; 9:e107289. [PMID: 25202966 PMCID: PMC4159350 DOI: 10.1371/journal.pone.0107289] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Accepted: 08/12/2014] [Indexed: 11/18/2022] Open
Abstract
Type II DNA topoisomerases are essential enzymes that catalyze topological rearrangement of double-stranded DNA using the free energy generated by ATP hydrolysis. Bacterial DNA gyrase is a prototype of this family and is composed of two subunits (GyrA, GyrB) that form a GyrA2GyrB2 heterotetramer. The N-terminal 43-kDa fragment of GyrB (GyrB43) from E. coli comprising the ATPase and the transducer domains has been studied extensively. The dimeric fragment is competent for ATP hydrolysis and its structure in complex with the substrate analog AMPPNP is known. Here, we have determined the remaining conformational states of the enzyme along the ATP hydrolysis reaction path by solving crystal structures of GyrB43 in complex with ADP⋅BeF3, ADP⋅Pi, and ADP. Upon hydrolysis, the enzyme undergoes an obligatory 12° domain rearrangement to accommodate the 1.5 Å increase in distance between the γ- and β-phosphate of the nucleotide within the sealed binding site at the domain interface. Conserved residues from the QTK loop of the transducer domain (also part of the domain interface) couple the small structural change within the binding site with the rigid body motion. The domain reorientation is reflected in a significant 7 Å increase in the separation of the two transducer domains of the dimer that would embrace one of the DNA segments in full-length gyrase. The observed conformational change is likely to be relevant for the allosteric coordination of ATP hydrolysis with DNA binding, cleavage/re-ligation and/or strand passage.
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Affiliation(s)
- Frédéric V. Stanger
- Focal Area Structural Biology and Biophysics, Biozentrum, University of Basel, Basel, Switzerland
- Focal Area Infection Biology, Biozentrum, University of Basel, Basel, Switzerland
| | - Christoph Dehio
- Focal Area Infection Biology, Biozentrum, University of Basel, Basel, Switzerland
| | - Tilman Schirmer
- Focal Area Structural Biology and Biophysics, Biozentrum, University of Basel, Basel, Switzerland
- * E-mail:
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Balaña-Fouce R, Alvarez-Velilla R, Fernández-Prada C, García-Estrada C, Reguera RM. Trypanosomatids topoisomerase re-visited. New structural findings and role in drug discovery. Int J Parasitol Drugs Drug Resist 2014; 4:326-37. [PMID: 25516844 PMCID: PMC4266802 DOI: 10.1016/j.ijpddr.2014.07.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
There is an urgent need of new treatments against trypanosomatids-borne diseases. DNA topoisomerases are pointed as potential drug targets against unicellular parasites. Trypanosomatids have a full set of DNA topoisomerases in both nucleus and kinetoplast. TopII and TopIII are located in the kinetoplast and fully involved in kDNA replication. Tritryps TopIB differ in structure from mammalian’s pointing to an attractive target.
The Trypanosomatidae family, composed of unicellular parasites, causes severe vector-borne diseases that afflict human populations worldwide. Chagas disease, sleeping sickness, as well as different sorts of leishmaniases are amongst the most important infectious diseases produced by Trypanosoma cruzi, Trypanosoma brucei and Leishmania spp., respectively. All these infections are closely related to weak health care services in low-income populations of less developed and least economically developed countries. Search for new therapeutic targets in order to hit these pathogens is of paramount priority, as no effective vaccine is currently in use against any of these parasites. Furthermore, present-day chemotherapy comprises old-fashioned drugs full of important side effects. Besides, they are prone to produce tolerance and resistance as a consequence of their continuous use for decades. DNA topoisomerases (Top) are ubiquitous enzymes responsible for solving the torsional tensions caused during replication and transcription processes, as well as in maintaining genomic stability during DNA recombination. As the inhibition of these enzymes produces cell arrest and triggers cell death, Top inhibitors are among the most effective and most widely used drugs in both cancer and antibacterial therapies. Top relaxation and decatenation activities, which are based on a common nicking–closing cycle involving one or both DNA strands, have been pointed as a promising drug target. Specific inhibitors that bind to the interface of DNA-Top complexes can stabilize Top-mediated transient DNA breaks. In addition, important structural differences have been found between Tops from the Trypanosomatidae family members and Tops from the host. Such dissimilarities make these proteins very interesting for drug design and molecular intervention. The present review is a critical update of the last findings regarding trypanosomatid’s Tops, their new structural features, their involvement both in the physiology and virulence of these parasites, as well as their use as promising targets for drug discovery.
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Affiliation(s)
- Rafael Balaña-Fouce
- Departamento de Ciencias Biomédicas, Universidad de León, Campus de Vegazana s/n, 24071 León, Spain
| | - Raquel Alvarez-Velilla
- Departamento de Ciencias Biomédicas, Universidad de León, Campus de Vegazana s/n, 24071 León, Spain
| | | | - Carlos García-Estrada
- Departamento de Ciencias Biomédicas, Universidad de León, Campus de Vegazana s/n, 24071 León, Spain
| | - Rosa M Reguera
- Departamento de Ciencias Biomédicas, Universidad de León, Campus de Vegazana s/n, 24071 León, Spain
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Roldan JLO, Blackledge M, van Nuland NAJ, Azuaga AI. Solution structure, dynamics and thermodynamics of the three SH3 domains of CD2AP. J Biomol NMR 2011; 50:103-117. [PMID: 21519904 DOI: 10.1007/s10858-011-9505-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2010] [Accepted: 02/24/2011] [Indexed: 05/30/2023]
Abstract
CD2 associated protein (CD2AP) is an adaptor protein that plays an important role in cell to cell union needed for the kidney function. It contains three N-terminal SH3 domains that are able to interact among others with CD2, ALIX, c-Cbl and Ubiquitin. To understand the role of the individual SH3 domains of this adaptor protein we have performed a complete structural, thermodynamic and dynamic characterization of the separate domains using NMR and DSC. The energetic contributions to the stability and the backbone dynamics have been related to the structural features of each domain using the structure-based FoldX algorithm. We have found that the N-terminal SH3 domain of both adaptor proteins CD2AP and CIN85 are the most stable SH3 domains that have been studied until now. This high stability is driven by a more extensive network of intra-molecular interactions. We believe that this increased stabilization of N-terminal SH3 domains in adaptor proteins is crucial to maintain the necessary conformation to establish the proper interactions critical for the recruitment of their natural targets.
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Affiliation(s)
- Jose L Ortega Roldan
- Departamento de Química Física e Instituto de Biotecnología, Universidad de Granada, Fuentenueva s/n, Spain
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Abstract
Type II topoisomerases are essential enzymes that regulate DNA under- and overwinding and remove knots and tangles from the genetic material. In order to carry out their critical physiological functions, these enzymes utilize a double-stranded DNA passage mechanism that requires them to generate a transient double-stranded break. Consequently, while necessary for cell survival, type II topoisomerases also have the capacity to fragment the genome. This feature of the prokaryotic and eukaryotic enzymes, respectively, is exploited to treat a variety of bacterial infections and cancers in humans. All type II topoisomerases require divalent metal ions for catalytic function. These metal ions function in two separate active sites and are necessary for the ATPase and DNA cleavage/ligation activities of the enzymes. ATPase activity is required for the strand passage process and utilizes the metal-dependent binding and hydrolysis of ATP to drive structural rearrangements in the protein. Both the DNA cleavage and ligation activities of type II topoisomerases require divalent metal ions and appear to utilize a novel variant of the canonical two-metal-ion phosphotransferase/hydrolase mechanism to facilitate these reactions. This article will focus primarily on eukaryotic type II topoisomerases and the roles of metal ions in the catalytic functions of these enzymes.
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Affiliation(s)
- Joseph E Deweese
- Department of Pharmaceutical Sciences, Lipscomb University College of Pharmacy, Nashville, TN 37204-3951, USA
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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 DOI: 10.1007/s00018-010-0299-5] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [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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