QUALITY CONTROL OF PHOTOSYSTEM II: HEAT-INDUCED CLEAVAGE OF THE REACTION CENTER D1 PROTEIN

摘要

Photosystem (PS) II is prone to various environmental stresses, the most prominent being strong visible light, and the behavior of the reaction center D1 protein under light stress has been studied extensively (Barber & Andersson 1992, Aro et al 1993,Yamamoto 2001). Another major stress to PS II is heat stress, however, only a limited number of studies have been reported with regards to this. Those studies that have been conducted include analysis of the changes in organization of PS II complexes inthe thylakoids (Gounaris et al 1983, Sundby et al 1986), release of extrinsic OEC subunits and Mn from PS II (Nash et al 1985), changes in the conformation of PS II (De Las Rivas & Barber 1997), and a rather preliminary study on degradation of the D1 protein (Singh & Singhal 1999). In the present work, we investigate cleavage of the D1 protein in detail under moderately elevated temperature conditions.