Crystal structure of DNA gyrase B' domain sheds lights on the mechanism for T-segment navigation.
DNA gyrase is an indispensible marvelous molecular machine in manipulating the DNA topology for the prokaryotes. In the 'two-gate' mechanism of DNA topoisomerase, T-segment navigation from N- to DNA-gate is a critical step, but the structural basis supporting this scheme is unclear. The crystal structure of DNA gyrase B' subfragment from Mycobacterium tuberculosis reveals an intrinsic homodimer. The two subunits, each consisting of a Tail and a Toprim domain, are tightly packed one another to form a 'crab-like' organization never observed previously from yeast topo II. Structural comparisons show two orientational alterations of the Tail domain, which may be dominated by a 43-residue peptide at the B' module C-terminus. A highly conserved pentapeptide mediates large-scale intrasubunit conformational change as a hinge point. Mutational studies highlight the significant roles of a negatively charge cluster on a groove at dimer interface. On the basis of structural analysis and mutation experiments, a sluice-like model for T-segment transport is proposed.
Fu
Guangsen
G
National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, People's Republic of China.
Wu
Jinjun
J
Liu
Wei
W
Zhu
Deyu
D
Hu
Yonglin
Y
Deng
Jiaoyu
J
Zhang
Xian-En
XE
Bi
Lijun
L
Wang
Da-Cheng
DC
D018360:Crystallography, X-Ray; D027081:DNA Gyrase / Q000737:chemistry* / Q000235:genetics; D019281:Dimerization; D008958:Models, Molecular; D009154:Mutation; D009169:Mycobacterium tuberculosis / Q000201:enzymology; D017434:Protein Structure, Tertiary; D021122:Protein Subunits / Q000737:chemistry / Q000235:genetics; D055672:Static Electricity
D021122:Protein Subunits; D027081:DNA Gyrase