title: Deacetylation of topoisomerase I is an important physiological function of E. coli CobB.
abstract: Escherichia coli topoisomerase I (TopA), a regulator of global and local DNA supercoiling, is modified by Nε-Lysine acetylation. The NAD+-dependent protein deacetylase CobB can reverse both enzymatic and non-enzymatic lysine acetylation modification in E. coli. Here, we show that the absence of CobB in a ΔcobB mutant reduces intracellular TopA catalytic activity and increases negative DNA supercoiling. TopA expression level is elevated as topA transcription responds to the increased negative supercoiling. The slow growth phenotype of the ΔcobB mutant can be partially compensated by further increase of intracellular TopA level via overexpression of recombinant TopA. The relaxation activity of purified TopA is decreased by in vitro non-enzymatic acetyl phosphate mediated lysine acetylation, and the presence of purified CobB protects TopA from inactivation by such non-enzymatic acetylation. The specific activity of TopA expressed from His-tagged fusion construct in the chromosome is inversely proportional to the degree of in vivo lysine acetylation during growth transition and growth arrest. These findings demonstrate that E. coli TopA catalytic activity can be modulated by lysine acetylation-deacetylation, and prevention of TopA inactivation from excess lysine acetylation and consequent increase in negative DNA supercoiling is an important physiological function of the CobB protein deacetylase.
authors.affiliation: Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, USA.|Biomolecular Sciences Institute, Florida International University, Miami, FL 33199, USA.
authors.forename: Qingxuan
authors.initials: Q
authors.lastname: Zhou
authors.affiliation: Transcription Control Section, RNA Biology Laboratory, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA.
authors.forename: Yan Ning
authors.initials: YN
authors.lastname: Zhou
authors.affiliation: Transcription Control Section, RNA Biology Laboratory, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA.
authors.forename: Ding Jun
authors.initials: DJ
authors.lastname: Jin
authors.affiliation: Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, USA.|Biomolecular Sciences Institute, Florida International University, Miami, FL 33199, USA.
authors.forename: Yuk-Ching
authors.initials: YC
authors.lastname: Tse-Dinh
mesh_terms: D000107:Acetylation; D055162:Biocatalysis; D002876:Chromosomes, Bacterial / Q000378:metabolism; D004264:DNA Topoisomerases, Type I / Q000378:metabolism*; D004269:DNA, Bacterial / Q000378:metabolism; D004278:DNA, Superhelical / Q000378:metabolism; D004587:Electrophoresis, Agar Gel; D004926:Escherichia coli / Q000254:growth & development / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000378:metabolism*; D008239:Lysine / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D010641:Phenotype; D011485:Protein Binding; D040901:Proteomics; D011994:Recombinant Proteins / Q000378:metabolism; D037761:Sirtuins / Q000378:metabolism*; D012995:Solubility
chemical_list: D004269:DNA, Bacterial; D004278:DNA, Superhelical; D029968:Escherichia coli Proteins; D011994:Recombinant Proteins; D037761:Sirtuins; C483998:cobB protein, E Coli; D004264:DNA Topoisomerases, Type I; D008239:Lysine