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The dimer state of GyrB is an active form: implications for the initial complex assembly and processive strand passage

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 ultra...

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Detalles Bibliográficos
Autores principales: Wu, Jinjun, Zhang, Zhiping, Mitchenall, Lesley A., Maxwell, Anthony, Deng, Jiaoyu, Zhang, Hongtai, Zhou, Ying, Chen, Yuan-yuan, Wang, Da-Cheng, Zhang, Xian-En, Bi, Lijun
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Oxford University Press 2011
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3201873/
https://www.ncbi.nlm.nih.gov/pubmed/21745817
http://dx.doi.org/10.1093/nar/gkr553
Descripción
Sumario: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.