Cyt c6-3: A new isoform of photosynthetic Cyt c6 exclusive to heterocyst-forming cyanobacteria
|Torrado Maya, Alejandro
Valladares Ruiz, Ana
Puerto Galán, Leonor
Hervás Morón, Manuel
Navarro Carruesco, José Antonio
Molina Heredia, Fernando Publio
|Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular
|All known cyanobacteria contain Cyt c6, a small soluble electron carrier protein whose main function is to transfer electrons from the Cyt b6 f complex to PSI, although it is also involved in respiration. We have previously ...
All known cyanobacteria contain Cyt c6, a small soluble electron carrier protein whose main function is to transfer electrons from the Cyt b6 f complex to PSI, although it is also involved in respiration. We have previously described a second isoform of this protein, the Cyt c6-like, whose function remains unknown. Here we describe a third isoform of Cyt c6 (here called Cytc6-3), which is only found in heterocyst- forming filamentous cyanobacteria. Cyt c6-3 is expressed in vegetative cells but is specifically repressed in heterocysts cells under diazotrophic growth conditions. Although there is a close structural similarity between Cyt c6-3 and Cyt c6 related to the general protein folding, Cyt c6-3 presents differential electrostatic surface features as compared with Cyt c6, its expression is not copper dependent and has a low reactivity towards PSI. According to the different expression pattern, functional reactivity and structural properties, Cyt c6-3 has to play an as yet to be defined regulatory role related to heterocyst differentiation.
|Torrado Maya, A., Valladares Ruiz, A., Puerto Galán, L., Hervás Morón, M., Navarro Carruesco, J.A. y Molina Heredia, F.P. (2017). Cyt c6-3: A new isoform of photosynthetic Cyt c6 exclusive to heterocyst-forming cyanobacteria. Plant and Cell Physiology, 58 (2), 256-265.