MISC

2007年1月

Structural and biochemical characterization of a cyanobacterium circadian clock-modifier protein

JOURNAL OF BIOLOGICAL CHEMISTRY
  • Kyouhei Arita
  • ,
  • Hiroshi Hashimoto
  • ,
  • Kumiko Igari
  • ,
  • Mayuko Akaboshi
  • ,
  • Shinsuke Kutsuna
  • ,
  • Mamoru Sato
  • ,
  • Toshiyuki Shimizu

282
2
開始ページ
1128
終了ページ
1135
記述言語
英語
掲載種別
DOI
10.1074/jbc.M608148200
出版者・発行元
AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC

Circadian clocks are self-sustained biochemical oscillators. The oscillator of cyanobacteria comprises the products of three kai genes (kaiA, kaiB, and kaiC). The autophosphorylation cycle of KaiC oscillates robustly in the cell with a 24-h period and is essential for the basic timing of the cyanobacterial circadian clock. Recently, period extender (pex), mutants of which show a short period phenotype, was classified as a resetting-related gene. In fact, pex mRNA and the pex protein (Pex) increase during the dark period, and a pex mutant subjected to diurnal light-dark cycles shows a 3-h advance in rhythm phase. Here, we report the x-ray crystallographic analysis and biochemical characterization of Pex from cyanobacterium Synechococcus elongatus PCC 7942. The molecule has an (alpha+beta) structure with a winged-helix motif and is indicated to function as a dimer. The subunit arrangement in the dimer is unique and has not been seen in other winged-helix proteins. Electrophoresis mobility shift assay using a 25-base pair complementary oligonucleotide incorporating the kaiA upstream sequence demonstrates that Pex has an affinity for the double-stranded DNA. Furthermore, mutation analysis shows that Pex uses the wing region to recognize the DNA. The in vivo rhythm assay of Pex shows that the constitutive expression of the pex gene harboring the mutation that fails to bind to DNA lacks the period-prolongation activity in the pex-deficient Synechococcus, suggesting that Pex is a DNA-binding transcription factor.

Web of Science ® 被引用回数 : 22

リンク情報
DOI
https://doi.org/10.1074/jbc.M608148200
CiNii Articles
http://ci.nii.ac.jp/naid/80018730357
PubMed
https://www.ncbi.nlm.nih.gov/pubmed/17098741
Web of Science
https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=JSTA_CEL&SrcApp=J_Gate_JST&DestLinkType=FullRecord&KeyUT=WOS:000243295200037&DestApp=WOS_CPL