Psbo Degradation by Deg Proteases under Reducing Conditions
DegP/HtrA proteases are ATP-independent serine endopeptidases widely distributed in nearly all organisms. As yet, their physiological role in oxygenic photosynthetic organisms is unclear, although it has been widely speculated that they participate in the Photosystem Ⅱ repair cycle. Here, we investigated the ability of Deg proteases to degrade PsbO according to its redox state. A sample of purified PsbO or Photosystem Ⅱ complex was incubated together with recombinant Deg proteases of Synechocystis sp. PCC 6803 (HhoA, HhoB or HtrA). The reducing media was conferred by the Escherichia coli thioredoxin/thioredoxin reductase system. The results obtained showed that HhoA is able to hydrolyze reduced PsbO while HhoB and HtrA are not. HhoA was active against free PsbO of spinach as well as PsbO of Synechocystis attached to Photosystem Ⅱ, only under reducing conditions. The finding that all three Deg proteases of Synechocystis co-purify with Photosystem Ⅱ supports the hypothesis of PsbO as a substrate for Deg proteases in vivo.
Deg proteases PsbO Protein degradation Thioredoxin Synechocystis Sp. PCC 6803
Irma N Roberts Helder Miranda L(a)m Xu(a)n T(a)m Thomas Kieselbach Christiane Funk
Department of Chemistry and Ume(a)Plant Science Centre, Ume(a) University, SE - 901 87 Ume(a), Swede Department of Chemistry and Ume(a) Plant Science Centre, Ume(a) University, SE - 901 87 Ume(a), Swed
国际会议
15th International Conference on Photosynthesis(第15届国际光合作用大会)
北京
英文
599-602
2010-08-22（万方平台首次上网日期，不代表论文的发表时间）