Complex formation of MukB, MukE and MukF proteins involved in chromosome partitioning in Escherichia coli

Yamazoe, Mitsuyoshi; Onogi, Toshinari; Sunako, Yumi; Niki, Hironori; Yamanaka, Kunitoshi; Ichimura, Toshiharu; Hiraga, Sota

doi:10.1093/emboj/18.21.5873

Cited by 119 publications

(122 citation statements)

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“…1A). Based on published data (17,20), the early elution time of MukF is expected due to dimerization and its non-globular asymmetric shape. The size exclusion chromatography profile showed some tailing of the MukF peak toward smaller molecular masses, suggesting either the equilibrium between various species or a nonideal interaction of MukF with the column resin.…”

Section: Resultsmentioning

confidence: 99%

“…Indeed, electron microscopy studies of MukB and MukBFE show that the MukE and MukF proteins mediate the formation of higher ordered structures that could work as chromatin scaffold (19). MukE forms a stable complex with MukF (20), but the stoichiometry and the biological relevance of such complex is still unclear. In the present work, we characterize the oligomerization states of MukE, MukF, and their complexes using size exclusion chromatography and analytical ultracentrifugation.…”

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confidence: 99%

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MukE and MukF Form Two Distinct High Affinity Complexes

Gloyd

Ghirlando

Matthews

et al. 2007

Journal of Biological Chemistry

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The MukBFE complex is essential for chromosome segregation and condensation in Escherichia coli. MukB is functionally related to the structural maintenance of chromosomes (SMC) proteins. Similar to SMCs, MukB requires accessory proteins (MukE and MukF) to form a functional complex for DNA segregation. MukF is a member of the kleisin family, which includes proteins that commonly mediate the interaction between SMCs and other accessory proteins, suggesting that the similarities between the MukBFE and the SMC complexes extend beyond MukB. Although SMCs have been carefully studied, little is known about the roles of their accessory components. In the present work, we characterize the oligomeric states of MukE and MukF using size exclusion chromatography and analytical ultracentrifugation. MukE self-associates to form dimers (K D 18 ؎ 3 M), which in turn interact with the MukF dimer to form two distinct high affinity complexes having 2:2 and 2:4 stoichiometries (F:E). Intermediate complexes are not found, and thus we propose that the equilibrium between these two complexes determines the formation of a functional MukBFE with stoichiometry 2:2:2.

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Section: Resultsmentioning

confidence: 99%

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confidence: 99%

MukE and MukF Form Two Distinct High Affinity Complexes

Gloyd

Ghirlando

Matthews

et al. 2007

Journal of Biological Chemistry

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“…To allow assessment of the role of ATP in MukB DNA binding, we developed a slightly different assay system. In experiments to be reported elsewhere, 4 using a large 11-kbp plasmid DNA, we have developed an assay to score MukB-mediated condensation of DNA. To remain consistent and to address the possibility that the large MukB protein might not interact with small plasmid DNAs in a manner reflective of how it interacts with chromosomal DNA, we used the same large, 11-kbp plasmid DNA in the experiments reported in this manuscript.…”

Section: Resultsmentioning

confidence: 99%

MukB-mediated Catenation of DNA Is ATP and MukEF Independent

Bahng

Hayama

Marians

2016

Journal of Biological Chemistry

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Edited by Patrick SungProperly condensed chromosomes are necessary for accurate segregation of the sisters after DNA replication. The Escherichia coli condesin is MukB, a structural maintenance of chromosomes (SMC)-like protein, which forms a complex with MukE and the kleisin MukF. MukB is known to be able to mediate knotting of a DNA ring, an intramolecular reaction. In our investigations of how MukB condenses DNA we discovered that it can also mediate catenation of two DNA rings, an intermolecular reaction. This activity of MukB requires DNA binding by the head domains of the protein but does not require either ATP or its partner proteins MukE or MukF. The ability of MukB to mediate DNA catenation underscores its potential for bringing distal regions of a chromosome together.The Escherichia coli chromosome is condensed about 1000-fold to fit into the nucleoid of the bacterium. A number of factors contribute to this extreme DNA condensation, among them are: DNA supercoiling, the binding of various nucleoid associated proteins like HU, Fis, and H-NS, and the binding of the structural maintenance of chromosomes (SMC) 3 -like condensin MukBEF (1, 2). SMC proteins act to manage the shape and behavior of chromosomes in both prokaryotes and eukaryotes (3). These proteins dimerize at a hinge region that is flanked by long coiled-coil regions that can be 40 -50 nm in length and that end in head domains that bind and hydrolyze ATP, as well as the bridging kleisin protein (MukF for the E. coli condensin (4)). The kleisin is then itself bound by another protein (MukE for the E. coli condensin (4)). There are three versions of the eukaryotic SMC proteins: the condensin, required for packaging of the chromosomes and comprised of SMC2 and SMC4; the cohesin, required for holding sister chromosomes together during mitosis and comprised of SMC1 and SMC3; and the SMC5-SMC6 complex, required for various aspects of DNA repair (3).It is generally acknowledged that the eukaryotic condensin and cohesin trap DNA topologically in the protein triangle formed by the SMC proteins and the kleisin (5, 6), although an alternative model for DNA binding for the eukaryotic cohesin exists (7). Recent reports suggest that the Bacillus subtilis SMC protein (8) and MukB (9) also trap chromosomes topologically. MukB binds linear and circular DNA in vitro and can induce negative supercoils and knots in relaxed circular DNA in the presence of a topoisomerase (10). Binding of MukB to chromosomal DNA in vivo requires ATP and MukEF (11, 12), although MukB DNA binding in vitro does not (10, 13).We (14) and the Burger and Oakley (15) labs have shown that the MukB hinge region interacts with the C-terminal ␤-propeller region of the ParC subunit of the cellular decatenase topoisomerase IV (Topo IV). We have reported (16) that this interaction stimulates the intramolecular activities of Topo IV, negative supercoil relaxation and knotting, but not the intermolecular activities of Topo IV, catenation/decatenation of DNA rings; whereas Berger, Oakley and colleag...

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“…As is the case for bacterial SMC proteins, two non-SMC accessory proteins, MukE and MukF, are required for full MukB function (29,30). Null mutations in the mukE or mukF genes, which are encoded within the same operon as MukB, result in a phenotype indistinguishable from that of a mukB − mutation (31).…”

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Escherichia coli condensin MukB stimulates topoisomerase IV activity by a direct physical interaction

Stewart

Berger

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

139

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In contrast to the current state of knowledge in the field of eukaryotic chromosome segregation, relatively little is known about the mechanisms coordinating the appropriate segregation of bacterial chromosomes. In Escherichia coli , the MukB/E/F complex and topoisomerase IV (Topo IV) are both crucial players in this process. Topo IV removes DNA entanglements following the replication of the chromosome, whereas MukB, a member of the structural maintenance of chromosomes protein family, serves as a bacterial condensin. We demonstrate here a direct physical interaction between the dimerization domain of MukB and the C-terminal domain of the ParC subunit of Topo IV. In addition, we find that MukB alters the activity of Topo IV in vitro. Finally, we isolate a MukB mutant, D692A, that is deficient in its interaction with ParC and show that this mutant fails to rescue the temperature-sensitive growth phenotype of a mukB - strain. These results show that MukB and Topo IV are linked physically and functionally and indicate that the activities of these proteins are not limited to chromosome segregation but likely also play a key role in the control of higher-order bacterial chromosome structure.

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Complex formation of MukB, MukE and MukF proteins involved in chromosome partitioning in Escherichia coli

Cited by 119 publications

References 35 publications

MukE and MukF Form Two Distinct High Affinity Complexes

MukE and MukF Form Two Distinct High Affinity Complexes

MukB-mediated Catenation of DNA Is ATP and MukEF Independent

Escherichia coli condensin MukB stimulates topoisomerase IV activity by a direct physical interaction

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