title: Physical and functional interaction between the condensin MukB and the decatenase topoisomerase IV in Escherichia coli.
abstract: Proper geometric and topological organization of DNA is essential for all chromosomal processes. Two classes of proteins play major roles in organizing chromosomes: condensin complexes and type II topoisomerases. In Escherichia coli, MukB, a structural maintenance of chromosome-like component of the bacterial condensin, and topoisomerase IV (Topo IV), a type II topoisomerase that decatenates the newly replicated daughter chromosomes, are both essential for chromosome segregation in rapidly growing cells. However, little is known about the interplay between MukB and Topo IV. Here we demonstrate a physical and functional interaction between MukB and ParC, a subunit of Topo IV, in vitro. The site of MukB interaction was located on the C-terminal domain of ParC and a loss-of-interaction mutant, ParC R705E R729A, was isolated. This variant retained full activity as a topoisomerase when reconstituted with ParE to form Topo IV. We show that MukB stimulates the superhelical DNA relaxation activity of wild-type Topo IV, but not that of Topo IV reconstituted with ParC R705E R729A.
authors.affiliation: Weill Cornell Graduate School of Medical Sciences, Memorial Sloan–Kettering Cancer Center, New York, NY 10065, USA.
authors.forename: Ryo
authors.initials: R
authors.lastname: Hayama
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: Marians
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism*; D019943:Amino Acid Substitution; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000378:metabolism*; D002876:Chromosomes, Bacterial / Q000235:genetics / Q000378:metabolism*; D004261:DNA Replication / Q000502:physiology; D027101:DNA Topoisomerase IV / Q000235:genetics / Q000378:metabolism*; D004269:DNA, Bacterial / Q000235:genetics / Q000378:metabolism; D004278:DNA, Superhelical / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D046912:Multiprotein Complexes / Q000235:genetics / Q000378:metabolism*; D020125:Mutation, Missense; D017434:Protein Structure, Tertiary
chemical_list: D002868:Chromosomal Proteins, Non-Histone; D004269:DNA, Bacterial; D004278:DNA, Superhelical; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C067035:MukB protein, E coli; D046912:Multiprotein Complexes; C108312:condensin complexes; D000251:Adenosine Triphosphatases; D027101:DNA Topoisomerase IV