title: DNA Gyrase of Deinococcus radiodurans is characterized as Type II bacterial topoisomerase and its activity is differentially regulated by PprA in vitro.
abstract: The multipartite genome of Deinococcus radiodurans forms toroidal structure. It encodes topoisomerase IB and both the subunits of DNA gyrase (DrGyr) while lacks other bacterial topoisomerases. Recently, PprA a pleiotropic protein involved in radiation resistance in D. radiodurans has been suggested for having roles in cell division and genome maintenance. In vivo interaction of PprA with topoisomerases has also been shown. DrGyr constituted from recombinant gyrase A and gyrase B subunits showed decatenation, relaxation and supercoiling activities. Wild type PprA stimulated DNA relaxation activity while inhibited supercoiling activity of DrGyr. Lysine133 to glutamic acid (K133E) and tryptophane183 to arginine (W183R) replacements resulted loss of DNA binding activity in PprA and that showed very little effect on DrGyr activities in vitro. Interestingly, wild type PprA and its K133E derivative continued interacting with GyrA in vivo while W183R, which formed relatively short oligomers did not interact with GyrA. The size of nucleoid in PprA mutant (1.9564 ± 0.324 µm) was significantly bigger than the wild type (1.6437 ± 0.345 µm). Thus, we showed that DrGyr confers all three activities of bacterial type IIA family DNA topoisomerases, which are differentially regulated by PprA, highlighting the significant role of PprA in DrGyr activity regulation and genome maintenance in D. radiodurans.
authors: Molecular Biology Division, Bhabha Atomic Research Centre, Mumbai, 400084, India.
authors: Swathi
authors: S
authors: Kota
authors: Molecular Biology Division, Bhabha Atomic Research Centre, Mumbai, 400084, India.
authors: Yogendra S
authors: YS
authors: Rajpurohit
authors: Molecular Biology Division, Bhabha Atomic Research Centre, Mumbai, 400084, India.|Department of Radiation Oncology, Houston Methodist Research Institute, Houston Methodist Hospital, Houston, TX, 77030, USA.
authors: Vijaya K
authors: VK
authors: Charaka
authors: Ion Beam Mutagenesis Research Group, Quantum Beam Science Center, Japan Atomic Energy Agency, Takasaki, Gunma, 370-1292, Japan.
authors: Katsuya
authors: K
authors: Satoh
authors: Radiation Microbiology Laboratory, Department of Life Sciences, Toyo University, Itakura, Gunma, 374-0193, Japan.
authors: Issay
authors: I
authors: Narumi
authors: Molecular Biology Division, Bhabha Atomic Research Centre, Mumbai, 400084, India. hsmisra@barc.gov.in.
authors: Hari S
authors: HS
authors: Misra
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D027081:DNA Gyrase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011088:DNA Ligases / Q000378:metabolism; D034301:Deinococcus / Q000201:enzymology* / Q000235:genetics; D009154:Mutation; D011485:Protein Binding; D000072417:Protein Domains; D021122:Protein Subunits / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D021122:Protein Subunits; D027081:DNA Gyrase; D011088:DNA Ligases
keywords: DNA gyrase; Deinococcus; Genome maintenance; PprA; Radioresistance