title: The dimer state of GyrB is an active form: implications for the initial complex assembly and processive strand passage.
abstract: In a previous study, we presented the dimer structure of DNA gyrase B' domain (GyrB C-terminal domain) from Mycobacterium tuberculosis and proposed a 'sluice-like' model for T-segment transport. However, the role of the dimer structure is still not well understood. Cross-linking and analytical ultracentrifugation experiments showed that the dimer structure exists both in the B' protein and in the full-length GyrB in solution. The cross-linked dimer of GyrB bound GyrA very weakly, but bound dsDNA with a much higher affinity than that of the monomer state. Using cross-linking and far-western analyses, the dimer state of GyrB was found to be involved in the ternary GyrA-GyrB-DNA complex. The results of mutational studies reveal that the dimer structure represents a state before DNA cleavage. Additionally, these results suggest that the dimer might also be present between the cleavage and reunion steps during processive transport.
authors: State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China.
authors: Jinjun
authors: J
authors: Wu
authors: Zhiping
authors: Z
authors: Zhang
authors: Lesley A
authors: LA
authors: Mitchenall
authors: Anthony
authors: A
authors: Maxwell
authors: Jiaoyu
authors: J
authors: Deng
authors: Hongtai
authors: H
authors: Zhang
authors: Ying
authors: Y
authors: Zhou
authors: Yuan-Yuan
authors: YY
authors: Chen
authors: Da-Cheng
authors: DC
authors: Wang
authors: Xian-En
authors: XE
authors: Zhang
authors: Lijun
authors: L
authors: Bi
mesh_terms: D055162:Biocatalysis; D004247:DNA / Q000737:chemistry* / Q000378:metabolism; D053837:DNA Cleavage; D027081:DNA Gyrase / Q000737:chemistry* / Q000378:metabolism; D019281:Dimerization; D008958:Models, Molecular; D009169:Mycobacterium tuberculosis / Q000201:enzymology*; D017434:Protein Structure, Tertiary; D021122:Protein Subunits / Q000378:metabolism
chemical_list: D021122:Protein Subunits; D004247:DNA; D027081:DNA Gyrase