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Physical Sciences and Mathematics

Marshall University

Chemistry Faculty Research

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Full-Text Articles in Life Sciences

Damped Oscillating Phosphoryl Transfer Reaction In The Cyanobacterial Circadian Clock, Hye In Jang, Pyonghwa Kim, Yongick Kim Mar 2023

Damped Oscillating Phosphoryl Transfer Reaction In The Cyanobacterial Circadian Clock, Hye In Jang, Pyonghwa Kim, Yongick Kim

Chemistry Faculty Research

Most organisms have circadian clocks to ensure the metabolic cycle to resonate with the rhythmic environmental changes without “damping,” or losing robustness. Cyanobacteria is the oldest and simplest form of life that is known to harbor this biological intricacy. Its KaiABC-based central oscillator proteins can be reconstituted inside a test tube, and the post-translational modification cycle occurs with 24 h periodicity. KaiC’s two major phosphorylation sites, Ser-431 and Thr-432, become phosphorylated and dephosphorylated by interacting with KaiA and KaiB, respectively. Here, we mutate Thr-432 into Ser to find the oscillatory phosphoryl transfer reaction damps. Previously, this mutant KaiC was reported …


The Circadian Clock—A Molecular Tool For Survival In Cyanobacteria, Pyonghwa Kim, Manpreet Kaur, Hye-In Jang, Yongick Kim Dec 2020

The Circadian Clock—A Molecular Tool For Survival In Cyanobacteria, Pyonghwa Kim, Manpreet Kaur, Hye-In Jang, Yongick Kim

Chemistry Faculty Research

Cyanobacteria are photosynthetic organisms that are known to be responsible for oxygenating Earth’s early atmosphere. Having evolved to ensure optimal survival in the periodic light/dark cycle on this planet, their genetic codes are packed with various tools, including a sophisticated biological timekeeping system. Among the cyanobacteria is Synechococcus elongatus PCC 7942, the simplest clock-harboring organism with a powerful genetic tool that enabled the identification of its intricate timekeeping mechanism. The three central oscillator proteins—KaiA, KaiB, and KaiC—drive the 24 h cyclic gene expression rhythm of cyanobacteria, and the “ticking” of the oscillator can be reconstituted inside a test tube just …