Reconstitution of circadian oscillation of cyanobacterial KaiC phosphorylation in vitro.
Kai proteins globally regulate circadian gene expression of cyanobacteria. The KaiC phosphorylation cycle, which persists even without transcription or translation, is assumed to be a basic timing process of the circadian clock. We have reconstituted the self-sustainable oscillation of KaiC phosphorylation in vitro by incubating KaiC with KaiA, KaiB, and adenosine triphosphate. The period of the in vitro oscillation was stable despite temperature change (temperature compensation), and the circadian periods observed in vivo in KaiC mutant strains were consistent with those measured in vitro. The enigma of the circadian clock can now be studied in vitro by examining the interactions between three Kai proteins.
Nakajima
Masato
M
Division of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan.
Imai
Keiko
K
Ito
Hiroshi
H
Nishiwaki
Taeko
T
Murayama
Yoriko
Y
Iwasaki
Hideo
H
Oyama
Tokitaka
T
Kondo
Takao
T
D000255:Adenosine Triphosphate; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002940:Circadian Rhythm; D056925:Circadian Rhythm Signaling Peptides and Proteins; D005798:Genes, Bacterial; D049449:Luminescence; D009154:Mutation; D010766:Phosphorylation; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D046940:Synechococcus / Q000235:genetics / Q000378:metabolism*; D013696:Temperature
D001426:Bacterial Proteins; D056925:Circadian Rhythm Signaling Peptides and Proteins; C114269:KaiA protein, cyanobacteria; C114270:KaiB protein, cyanobacteria; C114271:KaiC protein, cyanobacteria; D011994:Recombinant Proteins; D000255:Adenosine Triphosphate