PMID:20724474

Citation	Zhang, S, Frankel, LK and Bricker, TM (2010) The Sll0606 protein is required for photosystem II assembly/stability in the cyanobacterium Synechocystis sp. PCC 6803. J. Biol. Chem. 285:32047-54
Abstract	An insertional transposon mutation in the sll0606 gene was found to lead to a loss of photoautotrophy but not photoheterotrophy in the cyanobacterium Synechocystis sp. PCC 6803. Complementation analysis of this mutant (Tsll0606) indicated that an intact sll0606 gene could fully restore photoautotrophic growth. Gene organization in the vicinity of sll0606 indicates that it is not contained in an operon. No electron transport activity was detected in Tsll0606 using water as an electron donor and 2,6-dichlorobenzoquinone as an electron acceptor, indicating that Photosystem II (PS II) was defective. Electron transport activity using dichlorophenol indolephenol plus ascorbate as an electron donor to methyl viologen, however, was the same as observed in the control strain. This indicated that electron flow through Photosystem I was normal. Fluorescence induction and decay parameters verified that Photosystem II was highly compromised. The quantum yield for energy trapping by Photosystem II (F(V)/F(M)) in the mutant was less than 10% of that observed in the control strain. The small variable fluorescence yield observed after a single saturating flash exhibited aberrant Q(A)(-) reoxidation kinetics that were insensitive to dichloromethylurea. Immunological analysis indicated that whereas the D2 and CP47 proteins were modestly affected, the D1 and CP43 components were dramatically reduced. Analysis of two-dimensional blue native/lithium dodecyl sulfate-polyacrylamide gels indicated that no intact PS II monomer or dimers were observed in the mutant. The CP43-less PS II monomer did accumulate to detectable levels. Our results indicate that the Sll0606 protein is required for the assembly/stability of a functionally competent Photosystem II.
Links	PubMed PMC2952206 Online version:10.1074/jbc.M110.166983
Keywords	Electron Transport; Genetic Complementation Test; Photosynthetic Reaction Center Complex Proteins/genetics; Photosynthetic Reaction Center Complex Proteins/metabolism; Photosystem II Protein Complex/metabolism; Protein Stability; Synechocystis/cytology; Synechocystis/genetics; Synechocystis/metabolism
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
SYNY3:Q55723		GO:0010207: photosystem II assembly	ECO:0000315:		P		Figure 2 and Table 1. "No oxygen-evolving activity was observed in Tsll0606 cells when using ... as electron acceptors"	complete

References

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