The assembly of the photosystem II intermediate RC47 in plants involves the cooperation of the eukaryotic factor DEAP2 with PAM68The assembly of the photosystem II intermediate RC47 in plants involves the cooperation of the eukaryotic factor DEAP2 with PAM68

ABSTRACT: The initial step of oxygenic photosynthesis is the thermodynamically challenging extraction of electrons from water and release of molecular oxygen. This light-driven process, which allows for the life on Earth as we know it, is catalyzed by photosystem (PS) II in the thylakoid membrane of photosynthetic organisms. The biogenesis of PSII requires a controlled step-wise assembly process of which the early steps are considered to be highly conserved between plants and their cyanobacterial progenitors. The assembly process requires auxiliary proteins, which are likewise conserved. In the present work, we show that in plants, an important assembly step, in which the PSII reaction center (RC) is assembled with the intrinsic antenna protein CP47 to form RC47, requires the function of a eukaryotic factor. This factor, we named DEAP2 for decreased electron transport at PSII, works in concert with the conserved PAM68 assembly factor. deap2 mutants showed similar defects in PSII accumulation and assembly as pam68. The combined lack of both proteins results in a loss of functional PSII and inability of plants to grow photoautotrophically on soil. While overexpression of DEAP2 partially rescued the pam68 PSII accumulation phenotype, this was not reciprocal. We show DEAP2 to accumulate at twenty times higher levels than PAM68, together suggesting that both proteins have distinct functions. In summary, our results uncover eukaryotic adjustments to the PSII assembly process, which involve changes in the function of PAM68 and addition of DEAP2 as a stabilizing factor of the progression from RC to RC47.

ORGANISM(S): Arabidopsis Thaliana (mouse-ear Cress)

SUBMITTER: Iris Finkemeier 

PROVIDER: PXD041948 | JPOST Repository | Wed Nov 01 00:00:00 GMT 2023

REPOSITORIES: jPOST