title: Crystal structure of the MukB hinge domain with coiled-coil stretches and its functional implications.
abstract: The structural maintenance of chromosomes (SMC) family proteins are commonly found in the multiprotein complexes involved in chromosome organization, including chromosome condensation and sister chromatid cohesion. These proteins are characterized by forming a V-shaped homo- or heterodimeric structure with two long coiled-coil arms having two ATPase head domains at the distal ends. The hinge domain, located in the middle of the coiled coil, forms the dimer interface. In addition to being the dimerization module, SMC hinges appear to play other roles, including the gateway function for DNA entry into the cohesin complex. Herein, we report the homodimeric structure of the hinge domain of Escherichia coli MukB, which forms a prokaryotic condensin complex with two non-SMC subunits, MukE and MukF. In contrast with SMC hinge of Thermotoga maritima which has a sizable central hole at the dimer interface, MukB hinge forms a constricted dimer interface lacking a hole. Under our assay conditions, MukB hinge does not interact with DNA in accordance with the absence of a notable positively charged surface patch. The function of MukB hinge appears to be limited to dimerization of two copies of MukB molecules.
authors.affiliation: Department of Biological Sciences, KAIST Institute for the Biocentury, Daejeon, Korea.
authors.forename: Bonsu
authors.initials: B
authors.lastname: Ku
authors.forename: Jae-Hong
authors.initials: JH
authors.lastname: Lim
authors.forename: Ho-Chul
authors.initials: HC
authors.lastname: Shin
authors.forename: Seong-Yeol
authors.initials: SY
authors.lastname: Shin
authors.forename: Byung-Ha
authors.initials: BH
authors.lastname: Oh
mesh_terms: D000595:Amino Acid Sequence; D002868:Chromosomal Proteins, Non-Histone / Q000737:chemistry* / Q000378:metabolism*; D018360:Crystallography, X-Ray; D004247:DNA; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D018583:Pliability; D011485:Protein Binding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid; D040681:Structural Homology, Protein; D013329:Structure-Activity Relationship; D020124:Thermotoga maritima / Q000737:chemistry
chemical_list: D002868:Chromosomal Proteins, Non-Histone; D029968:Escherichia coli Proteins; C067035:MukB protein, E coli; D004247:DNA