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Updated: Aug 5, 2026
06:26
Isolation and Characterization of Intact Phycobilisome in Cyanobacteria
Published on: November 10, 2021
Calcium-induced PII oligomerization enhances physiological performance in the cyanobacterium Synechococcus elongatus
Neha Gupta1, Samujjal Bhattacharjee1, Ankit Srivastava1
1Laboratory of Microbial Genetics, Department of Botany, Institute of Science, Banaras Hindu University, Varanasi, 221005, India.
Archives of Microbiology
|July 28, 2026
Summary
Calcium ions (Ca²⁺) stabilize the PII protein in cyanobacteria, enhancing photosynthesis, growth, and stress resilience. This discovery reveals a new regulatory pathway for metabolic engineering in these organisms.
Area of Science:
- * Cyanobacterial physiology and metabolic regulation.
- * Molecular mechanisms of ion signaling.
Background:
- * Calcium (Ca²⁺) is a universal signaling ion, but its role in cyanobacteria is poorly understood.
- * The PII protein is a conserved regulator in cyanobacteria.
Purpose of the Study:
- * To investigate the link between Ca²⁺ availability and physiological responses in *Synechococcus elongatus* PCC 7942.
- * To elucidate the role of the PII protein in mediating Ca²⁺ effects.
Main Methods:
- * Physiological assays (cell viability, pigment accumulation, photosynthetic efficiency, ATP/ADP ratios).
- * Biochemical analyses (size-exclusion chromatography, Native PAGE, thermal aggregation assays).
- * Computational modeling to identify Ca²⁺-binding sites.
Main Results:
- * Ca²⁺ supplementation improved growth, photosynthesis, and energy status in wild-type cells, but not in PII-deficient mutants.
- * Ca²⁺ enhanced the stability of the PII trimer, with binding sites at subunit interfaces.
- * Stabilized PII improved carbon/nitrogen homeostasis, reduced storage pools, and mitigated oxidative stress.
Conclusions:
- * Ca²⁺ stabilizes the PII protein, linking calcium signaling to metabolic and physiological processes in cyanobacteria.
- * PII acts as an integrator of Ca²⁺ signals, impacting energy balance, photosynthesis, and stress resilience.
- * This Ca²⁺-PII regulatory axis is a potential target for metabolic engineering to enhance cyanobacterial biotechnology.
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