1
|
Madeddu F, Di Martino J, Pieroni M, Del Buono D, Bottoni P, Botta L, Castrignanò T, Saladino R. Molecular Docking and Dynamics Simulation Revealed the Potential Inhibitory Activity of New Drugs against Human Topoisomerase I Receptor. Int J Mol Sci 2022; 23:ijms232314652. [PMID: 36498979 PMCID: PMC9737192 DOI: 10.3390/ijms232314652] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 11/13/2022] [Accepted: 11/15/2022] [Indexed: 11/25/2022] Open
Abstract
Human Topoisomerase I (hTop1p) is a ubiquitous enzyme that relaxes supercoiled DNA through a conserved mechanism involving transient breakage, rotation, and binding. Htop1p is the molecular target of the chemotherapeutic drug camptothecin (CPT). It causes the hTop1p-DNA complex to slow down the binding process and clash with the replicative machinery during the S phase of the cell cycle, forcing cells to activate the apoptotic response. This gives hTop1p a central role in cancer therapy. Recently, two artesunic acid derivatives (compounds c6 and c7) have been proposed as promising inhibitors of hTop1p with possible antitumor activity. We used several computational approaches to obtain in silico confirmations of the experimental data and to form a comprehensive dynamic description of the ligand-receptor system. We performed molecular docking analyses to verify the ability of the two new derivatives to access the enzyme-DNA interface, and a classical molecular dynamics simulation was performed to assess the capacity of the two compounds to maintain a stable binding pose over time. Finally, we calculated the noncovalent interactions between the two new derivatives and the hTop1p receptor in order to propose a possible inhibitory mechanism like that adopted by CPT.
Collapse
Affiliation(s)
- Francesco Madeddu
- Department of Computer Science, “Sapienza” University of Rome, Piazzale Aldo Moro, 5, 00185 Rome, Italy
| | - Jessica Di Martino
- Department of Ecological and Biological Sciences, Tuscia University, Largo dell’Università snc, 01100 Viterbo, Italy
| | - Michele Pieroni
- Department of Computer Science, “Sapienza” University of Rome, Piazzale Aldo Moro, 5, 00185 Rome, Italy
| | - Davide Del Buono
- Department of Ecological and Biological Sciences, Tuscia University, Largo dell’Università snc, 01100 Viterbo, Italy
| | - Paolo Bottoni
- Department of Computer Science, “Sapienza” University of Rome, Piazzale Aldo Moro, 5, 00185 Rome, Italy
| | - Lorenzo Botta
- Department of Ecological and Biological Sciences, Tuscia University, Largo dell’Università snc, 01100 Viterbo, Italy
| | - Tiziana Castrignanò
- Department of Ecological and Biological Sciences, Tuscia University, Largo dell’Università snc, 01100 Viterbo, Italy
- Correspondence:
| | - Raffaele Saladino
- Department of Ecological and Biological Sciences, Tuscia University, Largo dell’Università snc, 01100 Viterbo, Italy
| |
Collapse
|
2
|
Dasari JB, Soren BC, Ottaviani A, Tesauro C, Marino S, Messina B, Fiorani P. Swapping of The N-Terminal Domain of Human Topoisomerase 1B with the Corresponding Plasmodium Falciparum Counterpart Strongly Impairs Enzyme Activity. Rep Biochem Mol Biol 2020; 8:366-375. [PMID: 32582794 PMCID: PMC7275839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 06/03/2019] [Indexed: 06/11/2023]
Abstract
BACKGROUND DNA topoisomerases 1B are a class of ubiquitous enzyme that solves the topological problems associated with biological processes such as replication, transcription and recombination. Numerous sequence alignment of topoisomerase 1B from different species shows that the lengths of different domains as well as their amino acids sequences are quite different. In the present study a hybrid enzyme, generated by swapping the N-terminal of Plasmodium falciparum into the corresponding domain of the human, has been characterized. METHODS The chimeric enzyme was generated using different sets of PCR. The in vitro characterization was carried out using different DNA substrate including radio-labelled oligonucleotides. RESULTS The chimeric enzyme displayed slower relaxation activity, cleavage and re-ligation kinetics strongly perturbed when compared to the human enzyme. CONCLUSION These results indicate that the N-terminal domain has a crucial role in modulating topoisomerase activity in different species.
Collapse
Affiliation(s)
- Jagadish Babu Dasari
- Department of Biology, University of Rome Tor Vergata, Via Della Ricerca Scientifica 1, 00133 Rome, Italy.
| | - Bini Chhetri Soren
- Department of Biology, University of Rome Tor Vergata, Via Della Ricerca Scientifica 1, 00133 Rome, Italy.
| | - Alessio Ottaviani
- Department of Biology, University of Rome Tor Vergata, Via Della Ricerca Scientifica 1, 00133 Rome, Italy.
- Institute of Translational Pharmacology, National Research Council, CNR, Via Del Fosso del Cavaliere 100, Rome 00133, Italy.
| | - Cinzia Tesauro
- Department of Biology, University of Rome Tor Vergata, Via Della Ricerca Scientifica 1, 00133 Rome, Italy.
- Present address: Department of Molecular Biology and Genetics, University of Aarhus, C.F MøllersAllè 3, 8000 Aarhus C, Denmark.
| | - Simona Marino
- Department of Biology, University of Rome Tor Vergata, Via Della Ricerca Scientifica 1, 00133 Rome, Italy.
| | - Beatrice Messina
- Department of Biology, University of Rome Tor Vergata, Via Della Ricerca Scientifica 1, 00133 Rome, Italy.
| | - Paola Fiorani
- Department of Biology, University of Rome Tor Vergata, Via Della Ricerca Scientifica 1, 00133 Rome, Italy.
- Institute of Translational Pharmacology, National Research Council, CNR, Via Del Fosso del Cavaliere 100, Rome 00133, Italy.
| |
Collapse
|
3
|
Wang Z, D'Annessa I, Tesauro C, Ottaviani A, Soren BC, Dasari JB, Messina B, Thareparambil A, Fiorani P. The human DNA topoisomerase I mutant Gly717Asp: Higher religation rate is not always associated with camptothecin resistance. Arch Biochem Biophys 2019; 663:165-172. [PMID: 30653963 DOI: 10.1016/j.abb.2019.01.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 01/07/2019] [Accepted: 01/09/2019] [Indexed: 11/15/2022]
Abstract
DNA topoisomerases are key enzyme responsible for modulating the topological state of the DNA by breaking and rejoining of DNA strand. Characterization of a Gly717Asp mutation in the human topoisomerase was performed using several catalytic assays. The mutant enzyme was shown to have comparable cleavage and fast religation rate as compared to the wild-type protein. Addition of the anticancer drug camptothecin significantly reduced the religation step. The simulative approaches and analysis of the cleavage/religation equilibrium indicate that the mutation is able to modify the architecture of the drug binding site, increasing the persistence of the drug for the enzyme-DNA covalent complex. Taken together these results indicate that the structure modification of the drug binding site is the key reason for the increasing CPT persistence and furthermore provide the possibility for new anti-cancer drug discovery.
Collapse
Affiliation(s)
- Zhenxing Wang
- Movement System Injury and Repair Research Center, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
| | - Ilda D'Annessa
- Department of Biology, University of Rome Tor Vergata, Via Della Ricerca Scientifica 1, 00133, Rome, Italy
| | - Cinzia Tesauro
- Department of Biology, University of Rome Tor Vergata, Via Della Ricerca Scientifica 1, 00133, Rome, Italy
| | - Alessio Ottaviani
- Department of Biology, University of Rome Tor Vergata, Via Della Ricerca Scientifica 1, 00133, Rome, Italy
| | - Bini Chhetri Soren
- Department of Biology, University of Rome Tor Vergata, Via Della Ricerca Scientifica 1, 00133, Rome, Italy
| | - Jagadish Babu Dasari
- Department of Biology, University of Rome Tor Vergata, Via Della Ricerca Scientifica 1, 00133, Rome, Italy
| | - Beatrice Messina
- Department of Biology, University of Rome Tor Vergata, Via Della Ricerca Scientifica 1, 00133, Rome, Italy
| | - Anil Thareparambil
- Department of Biology, University of Rome Tor Vergata, Via Della Ricerca Scientifica 1, 00133, Rome, Italy
| | - Paola Fiorani
- Department of Biology, University of Rome Tor Vergata, Via Della Ricerca Scientifica 1, 00133, Rome, Italy; Institute of Translational Pharmacology, National Research Council, CNR, Via Del Fosso del Cavaliere 100, Rome, 00133, Italy.
| |
Collapse
|
4
|
Cinelli MA. Topoisomerase 1B poisons: Over a half-century of drug leads, clinical candidates, and serendipitous discoveries. Med Res Rev 2018; 39:1294-1337. [PMID: 30456874 DOI: 10.1002/med.21546] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2018] [Revised: 10/08/2018] [Accepted: 10/09/2018] [Indexed: 12/17/2022]
Abstract
Topoisomerases are DNA processing enzymes that relieve supercoiling (torsional strain) in DNA, are necessary for normal cellular division, and act by nicking (and then religating) DNA strands. Type 1B topoisomerase (Top1) is overexpressed in certain tumors, and the enzyme has been extensively investigated as a target for cancer chemotherapy. Various chemical agents can act as "poisons" of the enzyme's religation step, leading to Top1-DNA lesions, DNA breakage, and eventual cellular death. In this review, agents that poison Top1 (and have thus been investigated for their anticancer properties) are surveyed, including natural products (such as camptothecins and indolocarbazoles), semisynthetic camptothecin and luotonin derivatives, and synthetic compounds (such as benzonaphthyridines, aromathecins, and indenoisoquinolines), as well as targeted therapies and conjugates. Top1 has also been investigated as a therapeutic target in certain viral and parasitic infections, as well as autoimmune, inflammatory, and neurological disorders, and a summary of literature describing alternative indications is also provided. This review should provide both a reference for the medicinal chemist and potentially offer clues to aid in the development of new Top1 poisons.
Collapse
Affiliation(s)
- Maris A Cinelli
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan
| |
Collapse
|
5
|
Zhang P, Zhang L, Zhang Y, Mao L, Jiang H. Substitutions in Spodoptera exigua topoisomerase I modulate its relaxation activity and camptothecin sensitivity. PEST MANAGEMENT SCIENCE 2017; 73:1179-1186. [PMID: 27643798 DOI: 10.1002/ps.4440] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 08/25/2016] [Accepted: 09/12/2016] [Indexed: 06/06/2023]
Abstract
BACKGROUND Topoisomerase I (Top I) is referred as the cellular target of the camptothecins (CPTs) which are now being explored as potential pesticides for insect control. Three amino acid substitutions, including L530P, A653T and S729T, in Top Is of insects were found in our previous studies. In order to investigate the effect of these three substitutions, a comparative analysis was conducted between the wild-type and mutant Top Is in Spodoptera exigua Hübner. RESULTS The optimal salt concentration of A653T and S729T was 150 mm, which is consistent with that of the wild-type Top I, while the mutant L530P showed maximum relaxation activity at a lower KCl concentration (100 mm). The mutated L530P and A653T Top Is showed a higher relaxation efficiency owing to an increased relaxation velocity toward the negatively supercoiled plasmid pBR322 DNA, which rendered L530P and A653T resistant to CPTs, whereas mutant S729T exhibited sensitivity to CPTs as a result of a decreased relaxation activity toward plasmid pBR322 DNA. CONCLUSIONS These results suggested that the polymorphism in Top I of insects was related to the biological activity of CPTs, which provided the basic information for reasonable usage of CPTs to control insect pests. © 2016 Society of Chemical Industry.
Collapse
Affiliation(s)
- Pei Zhang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Lan Zhang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yanning Zhang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Liangang Mao
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Hongyun Jiang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| |
Collapse
|
6
|
Affiliation(s)
- Giovanni Capranico
- Department
of Pharmacy and Biotechnology, University of Bologna, Via Belmeloro
8/2, 40126 Bologna, Italy
| | - Jessica Marinello
- Department
of Pharmacy and Biotechnology, University of Bologna, Via Belmeloro
8/2, 40126 Bologna, Italy
| | - Giovanni Chillemi
- SCAI
SuperComputing Applications and Innovation Department, Cineca, Via dei Tizii 6, 00185 Rome, Italy
| |
Collapse
|
7
|
Guruge AG, Udawatte C, Weerasinghe S. An In Silico Approach of Coumarin-Derived Inhibitors for Human DNA Topoisomerase I. Aust J Chem 2016. [DOI: 10.1071/ch16232] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Human topoisomerase I (Htopo I) is a vital target for anti-cancer agents; however, available anti-cancer agents are linked with several limitations. Therefore, designing novel inhibitors for Htopo I is significant. The rationale behind the current study is to identify novel coumarin inhibitors for Htopo I using in silico approaches and predict drug leads for in vitro studies. Using molecular docking and molecular dynamics, the binding affinities of 75 coumarins were compared with a known Htopo I inhibitor, topotecan. Docking studies predict three coumarins T1L25, T2L25, and T3L25 as most potent inhibitors for Htopo I. T2L25 gives the best grid score (–295 kJ mol–1), which is very comparable with that of topotecan (–302 kJ mol–1). The binding of these coumarins occurs preferentially via a planar geometry, and ligands bind at the binding site parallel to the axis of base pairing. NHCOCH3-substituted ligands are more favourable for binding when compared with the other substitute groups considered. The binding free energies calculated from molecular mechanics Poisson–Boltzmann surface area (MM-PBSA) method imply that T3L25 possesses the highest binding affinity when compared with the other two ligands. However, T1L25 and T2L25 have comparable binding free energies according to MM-PBSA calculations. Additionally, other calculated properties also support the suitability of these three derivatives as inhibitors for Htopo I. Therefore, the current study theoretically predicts three coumarin derivatives T1L25, T2L25, and T3L25 as potent inhibitors for Htopo I. These findings could lead to exploring novel non-camptothecin inhibitors for Htopo I.
Collapse
|
8
|
Huang NL, Lin JH. Recovery of the poisoned topoisomerase II for DNA religation: coordinated motion of the cleavage core revealed with the microsecond atomistic simulation. Nucleic Acids Res 2015; 43:6772-86. [PMID: 26150421 PMCID: PMC4538842 DOI: 10.1093/nar/gkv672] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 06/19/2015] [Indexed: 01/24/2023] Open
Abstract
Type II topoisomerases resolve topological problems of DNA double helices by passing one duplex through the reversible double-stranded break they generated on another duplex. Despite the wealth of information in the cleaving operation, molecular understanding of the enzymatic DNA ligation remains elusive. Topoisomerase poisons are widely used in anti-cancer and anti-bacterial therapy and have been employed to entrap the intermediates of topoisomerase IIβ with religatable DNA substrate. We removed drug molecules from the structure and conducted molecular dynamics simulations to investigate the enzyme-mediated DNA religation. The drug-unbound intermediate displayed transitions toward the resealing-compliant configuration: closing distance between the cleaved DNA termini, B-to-A transformation of the double helix, and restoration of the metal-binding motif. By mapping the contact configurations and the correlated motions between enzyme and DNA, we identified the indispensable role of the linker preceding winged helix domain (WHD) in coordinating the movements of TOPRIM, the nucleotide-binding motifs, and the bound DNA substrate during gate closure. We observed a nearly vectorial transition in the recovery of the enzyme and identified the previously uncharacterized roles of Asn508 and Arg677 in DNA rejoining. Our findings delineate the dynamic mechanism of the DNA religation conducted by type II topoisomerases.
Collapse
Affiliation(s)
- Nan-Lan Huang
- Research Center for Applied Sciences, Academia Sinica, Nangang, Taipei 11529, Taiwan
| | - Jung-Hsin Lin
- Research Center for Applied Sciences, Academia Sinica, Nangang, Taipei 11529, Taiwan Institute of Biomedical Sciences, Academia Sinica, Nangang, Taipei 11529, Taiwan School of Pharmacy, National Taiwan University, Taipei 10050, Taiwan
| |
Collapse
|
9
|
The human topoisomerase 1B Arg634Ala mutation results in camptothecin resistance and loss of inter-domain motion correlation. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2013; 1834:2712-21. [DOI: 10.1016/j.bbapap.2013.09.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Revised: 09/23/2013] [Accepted: 09/25/2013] [Indexed: 11/22/2022]
|
10
|
Siu FM, Pommier Y. Sequence selectivity of the cleavage sites induced by topoisomerase I inhibitors: a molecular dynamics study. Nucleic Acids Res 2013; 41:10010-9. [PMID: 24021629 PMCID: PMC3905861 DOI: 10.1093/nar/gkt791] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Topoisomerase IB (Top1) inhibitors, such as camptothecin (CPT), stabilize the Top1-DNA cleavage complex in a DNA sequence-dependent manner. The sequence selectivity of Top1 inhibitors is important for targeting specific genomic sequences of therapeutic value. However, the molecular mechanisms underlying this selectivity remain largely unknown. We performed molecular dynamics simulations to delineate structural, dynamic and energetic features that contribute to the differential sequence selectivity of the Top1 inhibitors. We found the sequence selectivity of CPT to be highly correlated with the drug binding energies, dynamic and structural properties of the linker domain. Chemical insights, gained by per-residue binding energy analysis revealed that the non-polar interaction between CPT and nucleotide at the +1 position of the cleavage site was the major (favorable) contributor to the total binding energy. Mechanistic insights gained by a potential of mean force analysis implicated that the drug dissociation step was associated with the sequence selectivity. Pharmaceutical insights gained by our molecular dynamics analyses explained why LMP-776, an indenoisoquinoline derivative under clinical development at the National Institutes of Health, displays different sequence selectivity when compared with camptothecin and its clinical derivatives.
Collapse
Affiliation(s)
- Fung-Ming Siu
- Center for High Performance Computing, Institute of Advanced Computing and Digital Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, 1068 Xueyuan Boulevard, University Town of Shenzhen, Xili Nanshan, Shenzhen 518055, China, Department of Chemistry and Institutes of Molecular Technology for Drug Discovery and Synthesis, State Key Laboratory of Synthetic Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong and Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
| | | |
Collapse
|
11
|
Arnò B, D’Annessa I, Tesauro C, Zuccaro L, Ottaviani A, Knudsen B, Fiorani P, Desideri A. Replacement of the human topoisomerase linker domain with the plasmodial counterpart renders the enzyme camptothecin resistant. PLoS One 2013; 8:e68404. [PMID: 23844196 PMCID: PMC3699648 DOI: 10.1371/journal.pone.0068404] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2013] [Accepted: 05/29/2013] [Indexed: 12/17/2022] Open
Abstract
A human/plasmodial hybrid enzyme, generated by swapping the human topoisomerase IB linker domain with the corresponding domain of the Plasmodium falciparum enzyme, has been produced and characterized. The hybrid enzyme displays a relaxation activity comparable to the human enzyme, but it is characterized by a much faster religation rate. The hybrid enzyme is also camptothecin resistant. A 3D structure of the hybrid enzyme has been built and its structural-dynamical properties have been analyzed by molecular dynamics simulation. The analysis indicates that the swapped plasmodial linker samples a conformational space much larger than the corresponding domain in the human enzyme. The large linker conformational variability is then linked to important functional properties such as an increased religation rate and a low drug reactivity, demonstrating that the linker domain has a crucial role in the modulation of the topoisomerase IB activity.
Collapse
Affiliation(s)
- Barbara Arnò
- Department of Biology and Interuniversity Consortium, National Institute Biostructure and Biosystem (INBB), University of Rome Tor Vergata, Rome, Italy
| | - Ilda D’Annessa
- Department of Biology and Interuniversity Consortium, National Institute Biostructure and Biosystem (INBB), University of Rome Tor Vergata, Rome, Italy
| | - Cinzia Tesauro
- Department of Biology and Interuniversity Consortium, National Institute Biostructure and Biosystem (INBB), University of Rome Tor Vergata, Rome, Italy
| | - Laura Zuccaro
- Department of Biology and Interuniversity Consortium, National Institute Biostructure and Biosystem (INBB), University of Rome Tor Vergata, Rome, Italy
| | - Alessio Ottaviani
- Department of Biology and Interuniversity Consortium, National Institute Biostructure and Biosystem (INBB), University of Rome Tor Vergata, Rome, Italy
| | - Birgitta Knudsen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Paola Fiorani
- Institute of Translational Pharmacology, National Research Council, CNR, Rome, Italy
| | - Alessandro Desideri
- Department of Biology and Interuniversity Consortium, National Institute Biostructure and Biosystem (INBB), University of Rome Tor Vergata, Rome, Italy
- * E-mail:
| |
Collapse
|
12
|
Ucuncuoglu N, Andricioaei I, Sari L. Insights from simulations into the mechanism of human topoisomerase I: Explanation for a seeming controversy in experiments. J Mol Graph Model 2013; 44:286-96. [DOI: 10.1016/j.jmgm.2013.07.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Revised: 07/01/2013] [Accepted: 07/05/2013] [Indexed: 11/27/2022]
|
13
|
A kinetic clutch governs religation by type IB topoisomerases and determines camptothecin sensitivity. Proc Natl Acad Sci U S A 2012; 109:16125-30. [PMID: 22991469 DOI: 10.1073/pnas.1206480109] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Type IB topoisomerases (Top1Bs) relax excessive DNA supercoiling associated with replication and transcription by catalyzing a transient nick in one strand to permit controlled rotation of the DNA about the intact strand. The natural compound camptothecin (CPT) and the cancer chemotherapeutics derived from it, irinotecan and topotecan, are highly specific inhibitors of human nuclear Top1B (nTop1). Previous work on vaccinia Top1B led to an elegant model that describes a straightforward dependence of rotation and religation on the torque caused by supercoiling. Here, we used a single-molecule DNA supercoil relaxation assay to measure the torque dependence of nTop1 and its inhibition by CPT. For comparison, we also examined mitochondrial Top1B and an N-terminal deletion mutant of nTop1. Despite substantial sequence homology in their core domains, nTop1 and mitochondrial Top1B exhibit dramatic differences in sensitivity to torque and CPT, with the N-terminal deletion mutant of nTop1 showing intermediate characteristics. In particular, nTop1 displays nearly torque-independent religation probability, distinguishing it from other Top1B enzymes studied to date. Kinetic modeling reveals a hitherto unobserved torque-independent transition linking the DNA rotation and religation phases of the enzymatic cycle. The parameters of this transition determine the torque sensitivity of religation and the efficiency of CPT binding. This "kinetic clutch" mechanism explains the molecular basis of CPT sensitivity and more generally provides a framework with which to interpret Top1B activity and inhibition.
Collapse
|
14
|
Ishikawa T, Krzysko KA, Kowalska-Loth B, Skrajna AM, Czubaty A, Girstun A, Cieplak MK, Lesyng B, Staron K. Activities of topoisomerase I in its complex with SRSF1. Biochemistry 2012; 51:1803-16. [PMID: 22320324 DOI: 10.1021/bi300043t] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Human DNA topoisomerase I (topo I) catalyzes DNA relaxation and phosphorylates SRSF1. Whereas the structure of topo I complexed with DNA has been resolved, the structure of topo I in the complex with SRSF1 and structural determinants of topo I activities in this complex are not known. The main obstacle to resolving the structure is a contribution of unfolded domains of topo I and SRSF1 in formation of the complex. To overcome this difficulty, we employed a three-step strategy: identifying the interaction regions, modeling the complex, and validating the model with biochemical methods. The binding sites in both topo I and SRSF1 are localized in the structured regions as well as in the unfolded domains. One observes cooperation between the binding sites in topo I but not in SRSF1. Our results indicate two features of the unfolded RS domain of SRSF1 containing phosphorylated residues that are critical for the kinase activity of topo I: its spatial arrangement relative to topo I and the organization of its sequence. The efficiency of phosphorylation of SRSF1 depends on the length and flexibility of the spacer between the two RRM domains that uniquely determine an arrangement of the RS domain relative to topo I. The spacer also influences inhibition of DNA nicking, a prerequisite for DNA relaxation. To be phosphorylated, the RS domain has to include a short sequence recognized by topo I. A lack of this sequence in the mutants of SRSF1 or its spatial inaccessibility in SRSF9 makes them inadequate as topo I/kinase substrates.
Collapse
Affiliation(s)
- Takao Ishikawa
- Institute of Biochemistry, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland
| | | | | | | | | | | | | | | | | |
Collapse
|
15
|
Mancini G, D'Annessa I, Coletta A, Sanna N, Chillemi G, Desideri A. Structural and dynamical effects induced by the anticancer drug topotecan on the human topoisomerase I - DNA complex. PLoS One 2010; 5:e10934. [PMID: 20532182 PMCID: PMC2880615 DOI: 10.1371/journal.pone.0010934] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2010] [Accepted: 05/06/2010] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Human topoisomerase I catalyzes the relaxation of DNA supercoils in fundamental cell processes like transcription, replication and chromosomal segregation. It is the only target of the camptothecin family of anticancer drugs. Among these, topotecan has been used to treat lung and ovarian carcinoma for several years. Camptothecins reversibly binds to the covalent intermediate DNA-enzyme, stabilizing the cleavable complex and reducing the religation rate. The stalled complex then collides with the progression of the replication fork, producing lethal double strand DNA breaks and eventually cell death. METHODOLOGY/PRINCIPAL FINDINGS Long lasting molecular dynamics simulations of the DNA-topoisomerase I binary complex and of the DNA-topoisomerase-topotecan ternary complex have been performed and compared. The conformational space sampled by the binary complex is reduced by the presence of the drug, as observed by principal component and cluster analyses. This conformational restraint is mainly due to the reduced flexibility of residues 633-643 (the region connecting the linker to the core domain) that causes an overall mobility loss in the ternary complex linker domain. During the simulation, DNA/drug stacking interactions are fully maintained, and hydrogen bonds are maintained with the enzyme. Topotecan keeps the catalytic residue Lys532 far from the DNA, making it unable to participate to the religation reaction. Arg364 is observed to interact with both the B and E rings of topotecan with two stable direct hydrogen bonds. An interesting constrain exerted by the protein on the geometrical arrangement of topotecan is also observed. CONCLUSIONS/SIGNIFICANCE Atomistic-scale understanding of topotecan interactions with the DNA-enzyme complex is fundamental to the explaining of its poisonous effect and of the drug resistance observed in several single residue topoisomerase mutants. We observed significant alterations due to topotecan in both short-range interactions and long-range protein domain communications.
Collapse
Affiliation(s)
- Giordano Mancini
- CASPUR Inter-University Consortium for the Application of Super-Computing for Universities and Research, Rome, Italy
| | - Ilda D'Annessa
- CASPUR Inter-University Consortium for the Application of Super-Computing for Universities and Research, Rome, Italy
- Department of Biology and Centro di Bioinformatica e Biostatistica, University of Rome Tor Vergata, Rome, Italy
| | - Andrea Coletta
- Department of Biology and Centro di Bioinformatica e Biostatistica, University of Rome Tor Vergata, Rome, Italy
| | - Nico Sanna
- CASPUR Inter-University Consortium for the Application of Super-Computing for Universities and Research, Rome, Italy
| | - Giovanni Chillemi
- CASPUR Inter-University Consortium for the Application of Super-Computing for Universities and Research, Rome, Italy
- * E-mail: (GC); (AD)
| | - Alessandro Desideri
- Department of Biology and Centro di Bioinformatica e Biostatistica, University of Rome Tor Vergata, Rome, Italy
- * E-mail: (GC); (AD)
| |
Collapse
|
16
|
Fiorani P, Tesauro C, Mancini G, Chillemi G, D'Annessa I, Graziani G, Tentori L, Muzi A, Desideri A. Evidence of the crucial role of the linker domain on the catalytic activity of human topoisomerase I by experimental and simulative characterization of the Lys681Ala mutant. Nucleic Acids Res 2009; 37:6849-58. [PMID: 19767617 PMCID: PMC2777420 DOI: 10.1093/nar/gkp669] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
The functional and structural-dynamical properties of the Lys681Ala mutation in the human topoisomerase IB linker domain have been investigated by catalytic assays and molecular dynamics simulation. The mutant is characterized by a comparable cleavage and a strongly reduced religation rate when compared to the wild type protein. The mutant also displays perturbed linker dynamics, as shown by analysis of the principal components of the motion, and a reduced electrostatic interaction with DNA. Inspection of the inter atomic distances in proximity of the active site shows that in the mutant the distance between the amino group of Lys532 side chain and the 5′ OH of the scissile phosphate is longer than the wild type enzyme, providing an atomic explanation for the reduced religation rate of the mutant. Taken together these results indicate the existence of a long range communication between the linker domain and the active site region and points out the crucial role of the linker in the modulation of the catalytic activity.
Collapse
Affiliation(s)
- Paola Fiorani
- Department of Biology, University of Rome Tor Vergata, CNR National Research Council, INFM National Institute for the Physics of Matter, Rome 00133, Italy
| | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Sanna N, Chillemi G, Gontrani L, Grandi A, Mancini G, Castelli S, Zagotto G, Zazza C, Barone V, Desideri A. UV-vis spectra of the anticancer camptothecin family drugs in aqueous solution: specific spectroscopic signatures unraveled by a combined computational and experimental study. J Phys Chem B 2009; 113:5369-75. [PMID: 19334673 DOI: 10.1021/jp809801y] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The ultraviolet-visible absorption spectrum of camptothecin (CPT) has been been recorded in aqueous solution at pH 5.3, where the equilibrium among the different CPT forms is shifted toward the lactonic one. Time-dependent density functional theory (TD-DFT) computations lead to a remarkable reproduction of the experimental spectrum only upon addition of explicit water molecules in interaction with specific moieties of the camptothecin molecule. Molecular dynamics (MD) simulations enforcing boundary periodic conditions for CPT embedded with 865 water molecules, with a force field derived from DFT computations, show that the experimental spectrum is due to the contributions of CPT molecules with different solvation patterns. A similar solvent effect is observed for several CPT derivatives, including the clinically relevant SN-38 and topotecan drugs. The quantitative agreement between TD-DFT/MD computations and experimental data allow us to identify specific spectroscopic signatures diagnostic of the drug environment and to develop procedures that can be used to monitor the drug-DNA/protein interaction.
Collapse
Affiliation(s)
- Nico Sanna
- CASPUR, Consortium for Supercomputing in Research, Via dei Tizii 6, 00185 Roma, Italy.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
18
|
Szklarczyk O, Staroń K, Cieplak M. Native state dynamics and mechanical properties of human topoisomerase I within a structure-based coarse-grained model. Proteins 2009; 77:420-31. [DOI: 10.1002/prot.22450] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
19
|
Abstract
DNA topoisomerases are a diverse set of essential enzymes responsible for maintaining chromosomes in an appropriate topological state. Although they vary considerably in structure and mechanism, the partnership between topoisomerases and DNA has engendered commonalities in how these enzymes engage nucleic acid substrates and control DNA strand manipulations. All topoisomerases can harness the free energy stored in supercoiled DNA to drive their reactions; some further use the energy of ATP to alter the topology of DNA away from an enzyme-free equilibrium ground state. In the cell, topoisomerases regulate DNA supercoiling and unlink tangled nucleic acid strands to actively maintain chromosomes in a topological state commensurate with particular replicative and transcriptional needs. To carry out these reactions, topoisomerases rely on dynamic macromolecular contacts that alternate between associated and dissociated states throughout the catalytic cycle. In this review, we describe how structural and biochemical studies have furthered our understanding of DNA topoisomerases, with an emphasis on how these complex molecular machines use interfacial interactions to harness and constrain the energy required to manage DNA topology.
Collapse
|
20
|
Chillemi G, D'Annessa I, Fiorani P, Losasso C, Benedetti P, Desideri A. Thr729 in human topoisomerase I modulates anti-cancer drug resistance by altering protein domain communications as suggested by molecular dynamics simulations. Nucleic Acids Res 2008; 36:5645-51. [PMID: 18765473 PMCID: PMC2553568 DOI: 10.1093/nar/gkn558] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
The role of Thr729 in modulating the enzymatic function of human topoisomerase I has been characterized by molecular dynamics (MD) simulation. In detail, the structural–dynamical behaviour of the Thr729Lys and the Thr729Pro mutants have been characterized because of their in vivo and in vitro functional properties evidenced in the accompanying paper. Both mutants can bind to the DNA substrate and are enzymatically active, but while Thr729Lys is resistant even at high concentration of the camptothecin (CPT) anti-cancer drug, Thr729Pro shows only a mild reduction in drug sensitivity and in DNA binding. MD simulations show that the Thr729Lys mutation provokes a structural perturbation of the CPT-binding pocket. On the other hand, the Thr729Pro mutant maintains the wild-type structural scaffold, only increasing its rigidity. The simulations also show the complete abolishment, in the Thr729Lys mutant, of the protein communications between the C-terminal domain (where the active Tyr723 is located) and the linker domain, that plays an essential role in the control of the DNA rotation, thus explaining the distributive mode of action displayed by this mutant.
Collapse
Affiliation(s)
- Giovanni Chillemi
- CASPUR Inter-University Consortium for the Application of Super-Computing for Universities and Research, Via dei Tizii 6, Rome 00185, Italy.
| | | | | | | | | | | |
Collapse
|
21
|
Chillemi G, Bruselles A, Fiorani P, Bueno S, Desideri A. The open state of human topoisomerase I as probed by molecular dynamics simulation. Nucleic Acids Res 2007; 35:3032-8. [PMID: 17439970 PMCID: PMC1888835 DOI: 10.1093/nar/gkm199] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The open state of human topoisomerase I has been probed by molecular dynamics simulation, starting from the coordinates of the closed structure of the protein complexed with DNA, after elimination of the 22-bp DNA duplex oligonucleotide. A repulsion force between the two lips of the protein has been introduced for a short time to induce destabilization of the local minimum, after which an unperturbed simulation has been carried out for 10 ns. The simulation shows that the protein undergoes a large conformational change due to rearrangements in the orientation of the protein domains, which however move as a coherent unit, fully maintaining their secondary and tertiary structures. Despite movements between the domains as large as 80-90 A, the catalytic pentad remains preassembled, the largest deviation of the active site backbone atoms from the starting crystallographic structure being only 1.7 A. Electrostatic calculation of the open protein structure shows that the protein displays a vast positive region with the active site residues located nearly at its center, in a conformation perfectly suited to interact with the negatively charged supercoiled DNA substrate.
Collapse
Affiliation(s)
- Giovanni Chillemi
- CASPUR Inter-University Consortium for the Application of Super-Computing for Universities and Research, Via dei Tizii 6, Rome 00185, Italy and INFM National Institute for the Physics of Matter, interdisciplinary Centre of Bioinformatics and Biostatistics and Department of Biology, University of Rome Tor Vergata, Via Della Ricerca Scientifica, Rome 00133, Italy
| | - Alessandro Bruselles
- CASPUR Inter-University Consortium for the Application of Super-Computing for Universities and Research, Via dei Tizii 6, Rome 00185, Italy and INFM National Institute for the Physics of Matter, interdisciplinary Centre of Bioinformatics and Biostatistics and Department of Biology, University of Rome Tor Vergata, Via Della Ricerca Scientifica, Rome 00133, Italy
| | - Paola Fiorani
- CASPUR Inter-University Consortium for the Application of Super-Computing for Universities and Research, Via dei Tizii 6, Rome 00185, Italy and INFM National Institute for the Physics of Matter, interdisciplinary Centre of Bioinformatics and Biostatistics and Department of Biology, University of Rome Tor Vergata, Via Della Ricerca Scientifica, Rome 00133, Italy
| | - Susana Bueno
- CASPUR Inter-University Consortium for the Application of Super-Computing for Universities and Research, Via dei Tizii 6, Rome 00185, Italy and INFM National Institute for the Physics of Matter, interdisciplinary Centre of Bioinformatics and Biostatistics and Department of Biology, University of Rome Tor Vergata, Via Della Ricerca Scientifica, Rome 00133, Italy
| | - Alessandro Desideri
- CASPUR Inter-University Consortium for the Application of Super-Computing for Universities and Research, Via dei Tizii 6, Rome 00185, Italy and INFM National Institute for the Physics of Matter, interdisciplinary Centre of Bioinformatics and Biostatistics and Department of Biology, University of Rome Tor Vergata, Via Della Ricerca Scientifica, Rome 00133, Italy
- *To whom correspondence should be addressed. +39 0672594376+39 062022798
| |
Collapse
|
22
|
Losasso C, Cretaio E, Palle K, Pattarello L, Bjornsti MA, Benedetti P. Alterations in linker flexibility suppress DNA topoisomerase I mutant-induced cell lethality. J Biol Chem 2007; 282:9855-9864. [PMID: 17276985 DOI: 10.1074/jbc.m608200200] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Eukaryotic DNA topoisomerase I (Top1p) catalyzes changes in DNA topology via the formation of a covalent enzyme-DNA intermediate, which is reversibly stabilized by the anticancer agent camptothecin (CPT). Crystallographic studies of the 70-kDa C terminus of human Top1p bound to duplex DNA describe a monomeric protein clamp circumscribing the DNA helix. The structures, which lack the N-terminal domain, comprise the conserved clamp, an extended linker domain, and the conserved C-terminal active site Tyr domain. CPT bound to the covalent Top1p-DNA complex limits linker flexibility, allowing structural determination of this domain. We previously reported that mutation of Ala(653) to Pro in the linker increases the rate of enzyme-catalyzed DNA religation, thereby rendering Top1A653Pp resistant to CPT (Fiorani, P., Bruselles, A., Falconi, M., Chillemi, G., Desideri, A., and Benedetti P. (2003) J. Biol. Chem. 278, 43268-43275). Molecular dynamics studies suggested mutation-induced increases in linker flexibility alter Top1p catalyzed DNA religation. To address the functional consequences of linker flexibility on enzyme catalysis and drug sensitivity, we investigated the interactions of the A653P linker mutation with a self-poisoning T718A mutation within the active site of Top1p. The A653P mutation suppressed the lethal phenotype of Top1T718Ap in yeast, yet did not restore enzyme sensitivity to CPT. However, the specific activity of the double mutant was decreased in vivo and in vitro, consistent with a decrease in DNA binding. These findings support a model where changes in the flexibility or orientation of the linker alter the geometry of the active site and thereby the kinetics of DNA cleavage/religation catalyzed by Top1p.
Collapse
Affiliation(s)
- Carmen Losasso
- Department of Biology, University of Padua, Padua 35131, Italy
| | - Erica Cretaio
- Department of Biology, University of Padua, Padua 35131, Italy
| | - Komaraiah Palle
- Department of Molecular Pharmacology, St. Jude Children's Research Hospital, Memphis, Tennessee 38104
| | - Luca Pattarello
- Department of Biology, University of Padua, Padua 35131, Italy
| | - Mary-Ann Bjornsti
- Department of Molecular Pharmacology, St. Jude Children's Research Hospital, Memphis, Tennessee 38104
| | - Piero Benedetti
- Department of Biology, University of Padua, Padua 35131, Italy.
| |
Collapse
|
23
|
Sanna N, Chillemi G, Grandi A, Castelli S, Desideri A, Barone V. New Hints on the pH-Driven Tautomeric Equilibria of the Topotecan Anticancer Drug in Aqueous Solutions from an Integrated Spectroscopic and Quantum-Mechanical Approach. J Am Chem Soc 2005; 127:15429-36. [PMID: 16262406 DOI: 10.1021/ja052637u] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The equilibria between the different forms of the topotecan anticancer drug have been studied at moderately acidic and physiological pH by an integrated computational tool rooted in the density functional theory and its time-dependent extension together with the polarizable continuum model. The results allow an unbiased selection between the different possible tautomeric forms and provide invaluable complements to experimental data. The ultraviolet-visible topotecan spectrum, recorded at moderately acidic pH, is accurately reproduced only by TD-DFT computations including solvent effects. Comparison of the experimental and calculated bands of the UV-vis spectrum at physiological pH indicates the presence of an equilibrium among different forms that is tuned by the microenvironment embedding the drug. The quantitative agreement between TD-DFT/PCM computations and experiments allows the identification of unequivocal spectroscopic signatures for different forms of topotecan.
Collapse
Affiliation(s)
- Nico Sanna
- CASPUR, Consortium for Supercomputing in Research, Via dei Tizii 6/b, 00185 Rome, Italy
| | | | | | | | | | | |
Collapse
|
24
|
Chillemi G, Fiorani P, Castelli S, Bruselles A, Benedetti P, Desideri A. Effect on DNA relaxation of the single Thr718Ala mutation in human topoisomerase I: a functional and molecular dynamics study. Nucleic Acids Res 2005; 33:3339-50. [PMID: 15944452 PMCID: PMC1145191 DOI: 10.1093/nar/gki642] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
The functional and dynamical properties of the human topoisomerase I Thr718Ala mutant have been compared to that of the wild-type enzyme using functional assays and molecular dynamics (MD) simulations. At physiological ionic strength, the cleavage and religation rates, evaluated on oligonucleotides containing the preferred topoisomerase I DNA sequence, are almost identical for the wild-type and the mutated enzymes, as is the cleavage/religation equilibrium. On the other hand, the Thr718Ala mutant shows a decreased efficiency in a DNA plasmid relaxation assay. The MD simulation, carried out on the enzyme complexed with its preferred DNA substrate, indicates that the mutant has a different dynamic behavior compared to the wild-type enzyme. Interestingly, no changes are observed in the proximity of the mutation site, whilst a different flexibility is detected in regions contacting the DNA scissile strand, such as the linker and the V-shaped α helices. Taken together, the functional and simulation results indicate a direct communication between the mutation site and regions located relatively far away, such as the linker domain, that with their altered flexibility confer a reduced DNA relaxation efficiency. These results provide evidence that the comprehension of the topoisomerase I dynamical properties are an important element in the understanding of its complex catalytic cycle.
Collapse
Affiliation(s)
- Giovanni Chillemi
- CASPUR Interuniversities Consortium for Supercomputing ApplicationsVia dei Tizii 6b, Rome 00185, Italy
| | - Paola Fiorani
- Department of Biology, National Institute for the Physics of Matter, University of Rome Tor VergataVia Della Ricerca Scientifica, Rome 00133, Italy
| | - Silvia Castelli
- Department of Biology, National Institute for the Physics of Matter, University of Rome Tor VergataVia Della Ricerca Scientifica, Rome 00133, Italy
| | - Alessandro Bruselles
- CASPUR Interuniversities Consortium for Supercomputing ApplicationsVia dei Tizii 6b, Rome 00185, Italy
- Department of Biology, National Institute for the Physics of Matter, University of Rome Tor VergataVia Della Ricerca Scientifica, Rome 00133, Italy
| | - Piero Benedetti
- Department of Biology, University of PaduaVia Ugo Bassi 58/B, Padua 35131, Italy
| | - Alessandro Desideri
- Department of Biology, National Institute for the Physics of Matter, University of Rome Tor VergataVia Della Ricerca Scientifica, Rome 00133, Italy
- To whom correspondence should be addressed. Tel: +39 06 72594376; Fax: +39 06 2022798;
| |
Collapse
|
25
|
Leppard JB, Champoux JJ. Human DNA topoisomerase I: relaxation, roles, and damage control. Chromosoma 2005; 114:75-85. [PMID: 15830206 DOI: 10.1007/s00412-005-0345-5] [Citation(s) in RCA: 161] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2005] [Revised: 03/29/2005] [Accepted: 03/30/2005] [Indexed: 11/28/2022]
Abstract
Human DNA topoisomerase I is an essential enzyme involved in resolving the torsional stress associated with DNA replication, transcription, and chromatin condensation. The catalytic cycle of the enzyme consists of DNA cleavage to form a covalent enzyme-DNA intermediate, DNA relaxation, and finally, re-ligation of the phosphate backbone to restore the continuity of the DNA. Structure/function studies have elucidated a flexible enzyme that relaxes DNA through coordinated, controlled movements of distinct enzyme domains. The cellular roles of topoisomerase I are apparent throughout the nucleus, but the concentration of processes acting on ribosomal DNA results in topoisomerase I accumulation in the nucleolus. Although the activity of topoisomerase I is required in these processes, the enzyme can also have a deleterious effect on cells. In the event that the final re-ligation step of the reaction cycle is prevented, the covalent topoisomerase I-DNA intermediate becomes a toxic DNA lesion that must be repaired. The complexities of the relaxation reaction, the cellular roles, and the pathways that must exist to repair topoisomerase I-mediated DNA damage highlight the importance of continued study of this essential enzyme.
Collapse
Affiliation(s)
- John B Leppard
- Department of Microbiology, School of Medicine, University of Washington, P.O. Box 357242, 1959 N.E. Pacific St., Seattle, WA 98195-7242, USA
| | | |
Collapse
|