The role of MukE in assembling a functional MukBEF complex.
The role of MukE in assembling a functional MukBEF complex.
复制标题
DOI：
10.1016/j.jmb.2011.08.009
复制
发表时间：
2011-09-30
影响因子：
5.6
通讯作者：
Guarné A
中科院分区：
文献类型：
--
作者：
Gloyd M;Ghirlando R;Guarné A
MukB-MukE-MukF蛋白复合物是大肠杆菌染色体凝聚和分离所必需的。该复合物的中心组分MukB蛋白在功能和结构上与普遍存在的SMC（染色体结构维持）蛋白相关。以类似于SMC的方式，MukB需要两个辅助蛋白（MukE和MukF）的结合才能发挥其功能。MukF是桥接MukB和MukE之间相互作用的组成型二聚体。虽然MukB可以自己浓缩DNA，但它需要MukF和MukE来确保正确的染色体分离。在这里，我们提出了一个新的结构的E。coliMukE-MukF复合物，其中复杂的晶体包装相互作用揭示了一个替代的MukE二聚化界面，跨越蛋白质的N-和C-末端翼螺旋结构域。该结构还揭示了由MukE介导的相邻MukE-MukF复合物之间的额外交联相互作用。包含这些表面之一上的点突变的MukE变体不影响MukB-MukE-MukF复合物的组装，并且还不能恢复mukE：：kan菌株的温度敏感性，这表明该表面可能介导MukB-MukE-MukF复合物之间的关键蛋白质-蛋白质相互作用。由于MukE的二聚化界面与MukB-MukE-MukF复合物中与MukB相互作用的蛋白质区域重叠，因此我们认为竞争性MukB-MukE和MukE-MukE相互作用可能调节细菌凝聚素高级结构的形成。
The MukB-MukE-MukF protein complex is essential for chromosome condensation and segregation in Escherichia coli. The central component of this complex, the MukB protein, is related functionally and structurally to the ubiquitous SMC (structural maintenance of chromosomes) proteins. In a manner similar to SMC, MukB requires the association of two accessory proteins (MukE and MukF) for its function. MukF is a constitutive dimer that bridges the interaction between MukB and MukE. While MukB can condense DNA on its own, it requires MukF and MukE to ensure proper chromosome segregation. Here, we present a novel structure of the E. coli MukE-MukF complex, in which the intricate crystal packing interactions reveal an alternative MukE dimerization interface spanning both N- and C-terminal winged helix domains of the protein. The structure also unveils additional cross-linking interactions between adjacent MukE-MukF complexes mediated by MukE. A variant of MukE encompassing point mutations on one of these surfaces does not affect assembly of the MukB-MukE-MukF complex and yet cannot restore the temperature sensitivity of the mukE::kan strain, suggesting that this surface may mediate critical protein-protein interactions between MukB-MukE-MukF complexes. Since the dimerization interface of MukE overlaps with the region of the protein that interacts with MukB in the MukB-MukE-MukF complex, we suggest that competing MukB-MukE and MukE-MukE interactions may regulate the formation of higher order structures of bacterial condensin.
登录
查看更多内容
DOI：
10.1107/s0907444904019158
发表时间：
2004-12-01
影响因子：
2.2
作者：
Emsley, P;Cowtan, K
通讯作者：
Cowtan, K
影响因子：
16
作者：
Haering, CH;Löwe, J;Nasmyth, K
通讯作者：
Nasmyth, K
影响因子：
3.4
作者：
Schuck, P
通讯作者：
Schuck, P
影响因子：
--
作者：
Mascarenhas, J;Volkov, AV;Graumann, PL
通讯作者：
Graumann, PL
影响因子：
4.8
作者：
Gloyd, Melanie;Ghirlando, Rodolfo;Guarne, Alba
通讯作者：
Guarne, Alba