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標題: Twisting of the DNA-binding surface by a beta-strand-bearing proline modulates DNA gyrase activity
作者: Hsieh, T.J.
Yen, T.J.
Lin, T.S.
Chang, H.T.
Huang, S.Y.
Hsu, C.H.
Farh, L.
Chan, N.L.
關鍵字: c-terminal domain;escherichia-coli;crystal-structure;ii;topoisomerase;protein;enzyme;chromosome;mechanism;iv
Project: Nucleic Acids Research
期刊/報告no:: Nucleic Acids Research, Volume 38, Issue 12, Page(s) 4173-4181.
DNA gyrase is the only topoisomerase capable of introducing (-) supercoils into relaxed DNA. The C-terminal domain of the gyrase A subunit (GyrA-CTD) and the presence of a gyrase-specific 'GyrA-box' motif within this domain are essential for this unique (-) supercoiling activity by allowing gyrase to wrap DNA around itself. Here we report the crystal structure of Xanthomonas campestris GyrA-CTD and provide the first view of a canonical GyrA-box motif. This structure resembles the GyrA-box-disordered Escherichia coli GyrA-CTD, both adopting a non-planar beta-pinwheel fold composed of six seemingly spirally arranged beta-sheet blades. Interestingly, structural analysis revealed that the non-planar architecture mainly stems from the tilted packing seen between blades 1 and 2, with the packing geometry likely being defined by a conserved and unusual beta-strand-bearing proline. Consequently, the GyrA-box-containing blade 1 is placed at an angled spatial position relative to the other DNA-binding blades, and an abrupt bend is introduced into the otherwise flat DNA-binding surface. Mutagenesis studies support that the proline-induced structural twist contributes directly to gyrase's (-) supercoiling activity. To our knowledge, this is the first demonstration that a beta-strand-bearing proline may impact protein function. Potential relevance of beta-strand-bearing proline to disease phenylketonuria is also noted.
ISSN: 0305-1048
DOI: 10.1093/nar/gkg153
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