Stoichiometric interactions between cyanobacterial clock proteins KaiA and KaiC

被引：50

作者：

Hayashi, F

Ito, H

Fujita, M

Iwase, R

Uzumaki, T

Ishiura, M ^{[1
]}

机构：

[1] Nagoya Univ, Ctr Gene Res, Nagoya, Aichi 4648602, Japan

[2] Nagoya Univ, BRAIN, Nagoya, Aichi 4648602, Japan

[3] Hitachi High Technol Corp, Customer Ctr, Atsugi, Kanagawa 2430123, Japan

[4] Nagoya Univ, Grad Sch Sci, Div Biol Sci, Nagoya, Aichi 4648602, Japan

来源：

BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS | 2004年 / 316卷 / 01期

基金：

日本学术振兴会;

关键词：

cyanobacteria; clock; KaiA; KaiC; interaction; stoichiometry; phosphorylation; IAsys;

D O I：

10.1016/j.bbrc.2004.02.034

中图分类号：

Q5 [生物化学]; Q7 [分子生物学];

学科分类号：

071010 ; 081704 ;

摘要：

We determined the stoichiometry of KaiA-KaiC interactions. Using immunoblotting and two-dimensional Native- and SDS-PAGE (2DNS-PAGE) analysis, we demonstrated that the reaction products of KaiA-KaiC interactions in the presence of ATP consisted of only phosphorylated KaiC whereas in the presence of the unhydrolyzable analogue 5'-adenylylimidodiphosphate (AMPPNP) they consisted of KaiA and KaiC. In the presence of ATP, the KE (molar ratio of KaiA dimer to KaiC hexamer giving half saturation in the enhancement of KaiC phosphorylation) was 0.25, and IAsys affinity biosensor analysis demonstrated that I molecule of KaiA dimer interacted with 1 molecule of KaiC hexamer. In the presence of AMPPNP, the ratio of KaiA dimer to KaiC hexamer in KaiA-KaiC complexes was determined to be 2 by 2DNS-PAGE, Native-PAGE/Scatchard plot, and IAsys analyses. These results suggest that 2 molecules of KaiA dimer can interact with I molecule of KaiC hexamer, and that interactions of at least I molecule of KaiA dimer with 1 molecule of KaiC hexamer are enough to enhance the phosphorylation of KaiC by KaiA at an almost saturated level. (C) 2004 Elsevier Inc. All rights reserved.

引用

页码：195 / 202

页数：8

共 22 条

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