The PsbH protein, a small subunit of the photosystem II complex (PSII), was identified as a 6-kDa protein band in the PSII core and subcore (CP47-D1-D2-cyt b-559) from the wild-type strain of the cyanobacterium Synechocystis PCC 6803. The protein was missing in the D1-D2-cytochrome b-559 complex and also in all PSII complexes isolated from IC7, a mutant lacking the psbH gene. The following properties of PSII in the mutant contrasted with those in wild-type: (a) CP47 was released during nondenaturing electrophoresis of the PSII core isolated from IC7; (b) depletion of CO2 resulted in a reversible decrease of the QA- reoxidation rate in the IC7 cells; (c) light-induced decrease in PSII activity, measured as 2,5-dimethyl-benzoquinone-supported Hill reaction, was strongly dependent on the HCO3- concentration in the IC7 cells; and (d) illumination of the IC7 cells lead to an extensive oxidation, fragmentation and cross-linking of the D1 protein. We did not find any evidence for phosphorylation of the PsbH protein in the wild-type strain. The results showed that in the PSII complex of Synechocystis attachment of CP47 to the D1-D2 heterodimer appears weakened and binding of bicarbonate on the PSII acceptor side is destabilized in the absence of the PsbH protein.

Photosynthesis Research Centre University of South Bohemia Ceské Budejovice Czech Republic

Citace poskytuje Crossref.org

The antenna-like domain of the cyanobacterial ferrochelatase can bind chlorophyll and carotenoids in an energy-dissipative configuration

The Ribosome-Bound Protein Pam68 Promotes Insertion of Chlorophyll into the CP47 Subunit of Photosystem II

The Psb27 assembly factor binds to the CP43 complex of photosystem II in the cyanobacterium Synechocystis sp. PCC 6803

Psb28 protein is involved in the biogenesis of the photosystem II inner antenna CP47 (PsbB) in the cyanobacterium Synechocystis sp. PCC 6803

Importance of the cyanobacterial Gun4 protein for chlorophyll metabolism and assembly of photosynthetic complexes

Role of the PsbI protein in photosystem II assembly and repair in the cyanobacterium Synechocystis sp. PCC 6803

The exposed N-terminal tail of the D1 subunit is required for rapid D1 degradation during photosystem II repair in Synechocystis sp PCC 6803

Autotrophic cells of the Synechocystis psbH deletion mutant are deficient in synthesis of CP47 and accumulate inactive PS II core complexes

Electron microscopy in structural studies of Photosystem II