Pressure accelerates the circadian clock of cyanobacteria

• Published in: Scientific reports Vol. 9; no. 1; pp. 12395 - 8
• Main Authors: Kitahara, Ryo, Oyama, Katsuaki, Kawamura, Takahiro, Mitsuhashi, Keita, Kitazawa, Soichiro, Yasunaga, Kazuhiro, Sagara, Natsuno, Fujimoto, Megumi, Terauchi, Kazuki
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 27.08.2019; Nature Publishing Group
• Subjects: 631/57/2272/2273; 631/57/2272/2276; 631/57/2272/951; 82; Adenosine triphosphatase; Adenosine Triphosphate - metabolism; Allosteric properties; Allosteric Regulation; ATP; Bacterial Proteins - chemistry; Bacterial Proteins - metabolism; Catalytic Domain; Circadian Clocks - genetics; Circadian rhythm; Circadian Rhythm Signaling Peptides and Proteins - chemistry; Circadian Rhythm Signaling Peptides and Proteins - metabolism; Circadian rhythms; Contraction; Cyanobacteria; Cyanobacteria - genetics; Cyanobacteria - metabolism; Humanities and Social Sciences; Hydrolysis; Hydrostatic Pressure; Kinetics; multidisciplinary; Phosphorylation; Pressure; Science; Science (multidisciplinary); Spectrometry, Fluorescence; Temperature tolerance; Thermodynamics
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-019-48693-1

Although organisms are exposed to various pressure and temperature conditions, information remains limited on how pressure affects biological rhythms. This study investigated how hydrostatic pressure affects the circadian clock (KaiA, KaiB, and KaiC) of cyanobacteria. While the circadian rhythm is inherently robust to temperature change, KaiC phosphorylation cycles that were accelerated from 22 h at 1 bar to 14 h at 200 bars caused the circadian-period length to decline. This decline was caused by the pressure-induced enhancement of KaiC ATPase activity and allosteric effects. Because ATPase activity was elevated in the CI and CII domains of KaiC, while ATP hydrolysis had negative activation volumes (Δ V ≠ ), both domains played key roles in determining the period length of the KaiC phosphorylation cycle. The thermodynamic contraction of the structure of the active site during the transition state might have positioned catalytic residues and lytic water molecules favourably to facilitate ATP hydrolysis. Internal cavities might represent sources of compaction and structural rearrangement in the active site. Overall, the data indicate that pressure differences could alter the circadian rhythms of diverse organisms with evolved thermotolerance, as long as enzymatic reactions defining period length have a specific activation volume.