Residues E318 and E319 of KaiC protein are indispensable for its phosphorylation, with E318 providing catalytic function and E319 mediating Mg2+ coordination.
Molecular dynamics simulations revealed that mutations at residues 318 and 319 reduce the stability of the KaiC protein, particularly the CII domain, increase solvent accessibility of phosphorylation sites, weaken rigidity near the ATP-binding pocket, and disrupt the Mg2+ coordination network. The study concludes that efficient KaiC phosphorylation requires the catalytic function of E318 and the Mg2+ coordination mediation by E319, both of which are indispensable.
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Residues E318 and E319 of KaiC protein are indispensable for its phosphorylation, with E318 providing catalytic function and E319 mediating Mg2+ coordination. The current body of evidence comprises 1 study. EvidenceHub rates the overall confidence at 24/100 (low).
The Claim
Residues E318 and E319 of KaiC protein are indispensable for its phosphorylation, with E318 providing catalytic function and E319 mediating Mg2+ coordination.
This conclusion is most relevant to: KaiC protein from cyanobacteria (in silico study).
What the Research Shows
The conclusion draws on 1 linked study. Highlights from the cited literature:
- ▸Regulation mechanism study of residues E318/319 for KaiC protein phosphorylation. (Biophysical journal, 2026) —
How It Works
The proposed biological pathway:
- ▸Mutations at E318/E319 reduce overall protein stability, especially in the CII domain
- ▸Phosphorylation sites become more accessible to solvent
- ▸Rigidity of residues near the ATP-binding pocket is weakened
- ▸Mg2+ coordination network is disrupted
- ▸Result: Phosphorylation is completely inhibited, as E318 is required for catalysis and E319 for Mg2+ coordination
Who Might Benefit
Evidence fit by population:
- ▸KaiC protein from cyanobacteria (in silico study)
Recommended Dose
N/A
Limitations & Caveats
Important context when interpreting this evidence:
- ▸Study is based on molecular dynamics simulations, not experimental validation in vivo
- ▸Findings are specific to cyanobacterial KaiC and may not directly translate to human circadian clock proteins
Frequently Asked Questions
What is the role of residue E318 in KaiC phosphorylation?▼
E318 provides catalytic function essential for efficient phosphorylation of KaiC.
How does residue E319 contribute to KaiC phosphorylation?▼
E319 mediates the coordination of Mg2+, which is necessary for the phosphorylation reaction.
What happens when residues 318 and 319 are mutated?▼
Mutations at these residues completely inhibit KaiC phosphorylation by reducing protein stability, increasing solvent accessibility of phosphorylation sites, weakening ATP-binding pocket rigidity, and disrupting Mg2+ coordination.
Could this research help with sleep disorders?▼
Yes, understanding the molecular mechanism of the cyanobacterial circadian clock may provide new intervention strategies for circadian rhythm disorders such as sleep disorders and metabolic syndrome.
References
- 1.Guo W, Zhao Y, Ke X, Feng H, Li A, Yan Y, Zhao Y. “Regulation mechanism study of residues E318/319 for KaiC protein phosphorylation..” Biophysical journal, 2026. PMID: 42324775 DOI: 10.1016/j.bpj.2026.06.023