2E1N

Crystal structure of the Cyanobacterium circadian clock modifier Pex

2E1N の概要

• エントリーDOI: 10.2210/pdb2e1n/pdb
• 分子名称: Pex, SULFATE ION (3 entities in total)
• 機能のキーワード: circadian clock, dna binding protein, circadian clock protein
• 由来する生物種: Synechococcus elongatus PCC 7942
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 32540.48

構造登録者

Arita, K.,Shimizu, T. (登録日: 2006-10-26, 公開日: 2006-11-28, 最終更新日: 2024-03-13)

主引用文献

Arita, K.,Hashimoto, H.,Igari, K.,Akaboshi, M.,Kutsuna, S.,Sato, M.,Shimizu, T.
Structural and Biochemical Characterization of a Cyanobacterium Circadian Clock-modifier Protein
J.Biol.Chem., 282:1128-1135, 2007

PubMed Abstract: 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.

PubMed: 17098741
DOI: 10.1074/jbc.M608148200

実験手法

X-RAY DIFFRACTION (1.8 Å)