Rapid interchange between two distinct forms of cyanobacterial photosystem II reaction-center protein D1 in response to photoinhibition.

摘要: Abstract We have studied photoinhibition of photosynthesis in the cyanobacterium Synechococcus sp. PCC 7942, which possesses two distinct forms photosystem II reaction-center protein D1 (D1:1 and D1:2). We report here that when cells adapted to a growth irradiance 50 mumol.m-2.s-1 are exposed an 500 mumol.m-2.s-1, normally predominant form (D1:1) is rapidly replaced with alternative D1:2. This interchange not only complete within first hour but also fully reversible once returned mumol.m-2 x s-1. By using mutant synthesizes D1:1, we show failure replace D1:1 D1:2 during results severe loss photosynthetic activity as well diminished capacity recover after stress period. believe this between may constitute active component protection mechanism unique among organisms enables cyanobacteria effectively cope from photoinhibition.