title: Purification of GidA protein, a novel topoisomerase II inhibitor produced by Streptomyces flavoviridis.
abstract: The presence of topoisomerase II inhibition activities in the intracellular extract of Streptomyces flavoviridis was investigated. One active compound inhibiting relaxation activity of topoisomerase II was determined to be a protein. This active principle was purified to homogeneity by gel filtration followed by ion exchange chromatography. The apparent molecular mass was 42 kDa as determined by SDS-PAGE. MALDI TOF peptide mass fingerprinting analysis confirmed this topoisomerase II inhibitor, as glucose-inhibited division protein A (GidA) by MOWSE score of 72. The effects of purified GidA protein on DNA relaxation and decatenation by topoisomerase II were investigated. It inhibited topoisomerase II activity and acted as a topoisomerase poison that significantly stabilized the covalent DNA-topoisomerase II reaction intermediate "cleavable complex", as observed with etoposide. Collectively, these findings indicate that GidA is a potent inhibitor of topoisomerase II enzyme, which can be exploited for rational drug design in human carcinomas.
authors.affiliation: Department of Microbial Biotechnology, School of Biotechnology and Genetic Engineering, Bharathiar University, Coimbatore, 641046, Tamil Nadu, India.
authors.forename: Antony K
authors.initials: AK
authors.lastname: Teresa Infanta S
authors.forename: S D
authors.initials: SD
authors.lastname: Nisshanthini
authors.forename: M
authors.initials: M
authors.lastname: Palaniswamy
authors.forename: J
authors.initials: J
authors.lastname: Angayarkanni
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D004247:DNA / Q000378:metabolism; D004250:DNA Topoisomerases, Type II / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*; D008970:Molecular Weight; D011485:Protein Binding; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013302:Streptomyces / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D004791:Enzyme Inhibitors; C108512:glucose-inhibited division protein A, bacteria; D004247:DNA; D004250:DNA Topoisomerases, Type II