2 research outputs found
New insights Into the evolution of the electron transfer from cytochrome f to photosystem I in the green and red branches of photosynthetic eukaryotes
In cyanobacteria and most green algae of the eukaryotic green lineage, the copper-protein plastocyanin (Pc) alternatively replaces the heme-protein cytochrome c6 (Cc6) as the soluble electron carrier from cytochrome f (Cf) to photosystem I (PSI). The functional and structural equivalence of 'green' Pc and Cc6 has been well established, representing an example of convergent evolution of two unrelated proteins. However, plants only produce Pc, despite having evolved from green algae. On the other hand, Cc6 is the only soluble donor available in most species of the red lineage of photosynthetic organisms, which includes, among others, red algae and diatoms. Interestingly, Pc genes have been identified in oceanic diatoms, probably acquired by horizontal gene transfer from green algae. However, the mechanisms that regulate the expression of a functional Pc in diatoms are still unclear. In the green eukaryotic lineage, the transfer of electrons from Cf to PSI has been characterized in depth. The conclusion is that in the green lineage, this process involves strong electrostatic interactions between partners, which ensure a high affinity and an efficient electron transfer (ET) at the cost of limiting the turnover of the process. In the red lineage, recent kinetic and structural modeling data suggest a different strategy, based on weaker electrostatic interactions between partners, with lower affinity and less efficient ET, but favoring instead the protein exchange and the turnover of the process. Finally, in diatoms the interaction of the acquired green-Type Pc with both Cf and PSI may not yet be optimized.Ministerio de EconomÃa, Industria y Competitividad BIO2015-64169-P, BIO2016-79930-RJunta de AndalucÃa PAIDI BIO-02
New insights into the evolution of the electron transfer from cytochrome f to photosystem i in the green and red branches of photosynthetic eukaryotes
In cyanobacteria and most green algae of the eukaryotic
green lineage, the copper-protein plastocyanin (Pc) alternatively
replaces the heme-protein cytochrome c6 (Cc6) as the
soluble electron carrier from cytochrome f (Cf) to photosystem
I (PSI). The functional and structural equivalence of
‘green’ Pc and Cc6 has been well established, representing an
example of convergent evolution of two unrelated proteins.
However, plants only produce Pc, despite having evolved
from green algae. On the other hand, Cc6 is the only soluble
donor available in most species of the red lineage of photosynthetic
organisms, which includes, among others, red
algae and diatoms. Interestingly, Pc genes have been identified
in oceanic diatoms, probably acquired by horizontal
gene transfer from green algae. However, the mechanisms
that regulate the expression of a functional Pc in diatoms are
still unclear. In the green eukaryotic lineage, the transfer of
electrons from Cf to PSI has been characterized in depth.
The conclusion is that in the green lineage, this process
involves strong electrostatic interactions between partners,
which ensure a high affinity and an efficient electron transfer
(ET) at the cost of limiting the turnover of the process. In the
red lineage, recent kinetic and structural modeling data suggest
a different strategy, based on weaker electrostatic interactions
between partners, with lower affinity and less efficient
ET, but favoring instead the protein exchange and the
turnover of the process. Finally, in diatoms the interaction of
the acquired green-type Pc with both Cf and PSI may not yet
be optimized.Peer reviewe