Universität zu Köln

Wiegard, Anika ORCID: 0000-0001-9674-0510, Koebler, Christin, Oyama, Katsuaki, Doerrich, Anja K., Azai, Chihiro, Terauchi, Kazuki, Wilde, Annegret ORCID: 0000-0003-0935-8415 and Axmann, Ilka M. (2020). Synechocystis KaiC3 Displays Temperature- and KaiB-Dependent ATPase Activity and Is Important for Growth in Darkness. J. Bacteriol., 202 (4). WASHINGTON: AMER SOC MICROBIOLOGY. ISSN 1098-5530

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Abstract

Cyanobacteria form a heterogeneous bacterial group with diverse lifestyles, acclimation strategies, and differences in the presence of circadian clock proteins. In Synechococcus elongatus PCC 7942, a unique posttranslational KaiABC oscillator drives circadian rhythms. ATPase activity of KaiC correlates with the period of the clock and mediates temperature compensation. Synechocystis sp. strain PCC 6803 expresses additional Kai proteins, of which KaiB3 and KaiC3 proteins were suggested to fine-tune the standard KaiAB1C1 oscillator. In the present study, we therefore characterized the enzymatic activity of KaiC3 as a representative of nonstandard KaiC homologs in vitro. KaiC3 displayed ATPase activity lower than that of the Synechococcus elongatus PCC 7942 KaiC protein. ATP hydrolysis was temperature dependent. Hence, KaiC3 is missing a defining feature of the model cyanobacterial circadian oscillator. Yeast two-hybrid analysis showed that KaiC3 interacts with KaiB3, KaiC1, and KaiB1. Further, KaiB3 and KaiB1 reduced in vitro ATP hydrolysis by KaiC3. Spot assays showed that chemoheterotrophic growth in constant darkness is completely abolished after deletion of Delta kaiAB1C1 and reduced in the absence of kaiC3. We therefore suggest a role for adaptation to darkness for KaiC3 as well as a cross talk between the KaiC1- and KaiC3-based systems. IMPORTANCE The circadian clock influences the cyanobacterial metabolism, and deeper understanding of its regulation will be important for metabolic optimizations in the context of industrial applications. Due to the heterogeneity of cyanobacteria, characterization of clock systems in organisms apart from the circadian model Synechococcus elongatus PCC 7942 is required. Synechocystis sp. strain PCC 6803 represents a major cyanobacterial model organism and harbors phylogenetically diverged homologs of the clock proteins, which are present in various other noncyanobacterial prokaryotes. By our in vitro studies we unravel the interplay of the multiple Synechocystis Kai proteins and characterize enzymatic activities of the nonstandard clock homolog KaiC3. We show that the deletion of kaiC3 affects growth in constant darkness, suggesting its involvement in the regulation of nonphotosynthetic metabolic pathways.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Wiegard, Anika UNSPECIFIED orcid.org/0000-0001-9674-0510 UNSPECIFIED Koebler, Christin UNSPECIFIED UNSPECIFIED UNSPECIFIED Oyama, Katsuaki UNSPECIFIED UNSPECIFIED UNSPECIFIED Doerrich, Anja K. UNSPECIFIED UNSPECIFIED UNSPECIFIED Azai, Chihiro UNSPECIFIED UNSPECIFIED UNSPECIFIED Terauchi, Kazuki UNSPECIFIED UNSPECIFIED UNSPECIFIED Wilde, Annegret UNSPECIFIED orcid.org/0000-0003-0935-8415 UNSPECIFIED Axmann, Ilka M. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-347647
DOI:	10.1128/JB.00478-19
Journal or Publication Title:	J. Bacteriol.
Volume:	202
Number:	4
Date:	2020
Publisher:	AMER SOC MICROBIOLOGY
Place of Publication:	WASHINGTON
ISSN:	1098-5530
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language CIRCADIAN CLOCK PROTEIN; CYANOBACTERIAL CLOCK; OSCILLATOR; PHOSPHORYLATION; COMPENSATION; EXPRESSION; DIVERSITY; MECHANISM; SUBSTRAIN; GENES Multiple languages Microbiology Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/34764