PsbY is required for prevention of photodamage to photosystem II in a PsbM-lacking mutant of Synechocystis sp. PCC 6803 |
| |
Authors: | S. Biswas J. J. Eaton-Rye |
| |
Affiliation: | 1.Department of Biochemistry,University of Otago,Dunedin,New Zealand |
| |
Abstract: | The PsbM (3.9 kDa) and PsbY (4.2 kDa) proteins are membrane-spanning, single-helix, subunits associated with the chlorophyll-binding CP47 pre-complex of photosystem II (PSII). Removal of PsbM resulted in accumulation of PSII pre-assembly complexes and impaired electron transfer between the primary (QA) and secondary (QB) plastoquinone electron acceptors of PSII indicating that the QB-binding site and bicarbonate binding to the non-heme iron were altered in this strain. Removal of PsbY alone had only a minor impact on PSII activity but deleting PsbY in the ΔPsbM background led to additional modification of the acceptor side resulting in ΔPsbM:ΔPsbY cells being susceptible to photodamage and this required protein synthesis for recovery. Addition of bicarbonate was able to compensate for the light-induced damage in ΔPsbM:ΔPsbY cells potentially re-occupying the modified bicarbonate-binding site in the ΔPsbM:ΔPsbY strain and complementation of ΔPsbM:ΔPsbY cells with the psbY gene restored the ΔPsbM phenotype. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |