title: Investigating direct interaction between Escherichia coli topoisomerase I and RecA.
abstract: Protein-protein interactions are of special importance in cellular processes, including replication, transcription, recombination, and repair. Escherichia coli topoisomerase I (EcTOP1) is primarily involved in the relaxation of negative DNA supercoiling. E. coli RecA, the key protein for homologous recombination and SOS DNA-damage response, has been shown to stimulate the relaxation activity of EcTOP1. The evidence for their direct protein-protein interaction has not been previously established. We report here the direct physical interaction between E. coli RecA and topoisomerase I. We demonstrated the RecA-topoisomerase I interaction via pull-down assays, and surface plasmon resonance measurements. Molecular docking supports the observation that the interaction involves the topoisomerase I N-terminal domains that form the active site. Our results from pull-down assays showed that ATP, although not required, enhances the RecA-EcTOP1 interaction. We propose that E. coli RecA physically interacts with topoisomerase I to modulate the chromosomal DNA supercoiling.
authors.affiliation: Department of Chemistry and Biochemistry, Florida International University, Miami, Florida, USA.
authors.forename: Srikanth
authors.initials: S
authors.lastname: Banda
authors.affiliation: Department of Oncology, Georgetown University, Washington, District of Columbia, USA.
authors.forename: Purushottam Babu
authors.initials: PB
authors.lastname: Tiwari
authors.affiliation: Department of Physics, Florida International University, Miami, Florida, USA.
authors.forename: Yesim
authors.initials: Y
authors.lastname: Darici
authors.affiliation: Department of Chemistry and Biochemistry, Florida International University, Miami, Florida, USA.|Biomolecular Sciences Institute, Florida International University, Miami, Florida, USA.
authors.forename: Yuk-Ching
authors.initials: YC
authors.lastname: Tse-Dinh
mesh_terms: D020134:Catalytic Domain / Q000235:genetics; D004264:DNA Topoisomerases, Type I / Q000235:genetics*; D004278:DNA, Superhelical / Q000235:genetics*; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism; D059765:Homologous Recombination / Q000235:genetics; D062105:Molecular Docking Simulation; D011938:Rec A Recombinases / Q000235:genetics*; D013014:SOS Response, Genetics / Q000235:genetics; D020349:Surface Plasmon Resonance
chemical_list: D004278:DNA, Superhelical; D011938:Rec A Recombinases; D004264:DNA Topoisomerases, Type I
keywords: DNA topoisomerase I; Molecular docking; Protein–protein interactions; Pull-down assay; RecA; SPR