Barbato R, Friso G, de Laureto P P, Frizzo A, Rigoni F, Giacometti G M
Dipartimento di Biologia dell'Università di Padova, Italy.
FEBS Lett. 1992 Oct 12;311(1):33-6. doi: 10.1016/0014-5793(92)81360-x.
When isolated photosystem II reaction centers from spinach are exposed to photoinhibitory light in the presence of an electron acceptor, breakdown products of the D2 protein at 28, 25, 23, 18, 9, 5 and 4.5 kDa are detected by immunoblotting with a monospecific anti-D2 polyclonal antibody. In a time-course experiment the 23 and 4.5 kDa fragments show a transient appearance, whilst the others are photoaccumulated. The regions of the D2 protein containing the cleavage sites for the 28 and 18 kDa photoinduced fragments have been identified. Significant degradation of D2 takes place only in the presence of an electron acceptor, and breakdown of the protein is partially prevented by serine-type protease inhibitors.
当来自菠菜的分离的光系统II反应中心在电子受体存在的情况下暴露于光抑制光时，用单特异性抗D2多克隆抗体通过免疫印迹检测到28、25、23、18、9、5和4.5 kDa的D2蛋白降解产物。在时间进程实验中，23和4.5 kDa的片段呈现短暂出现，而其他片段则光积累。已经确定了D2蛋白中包含28和18 kDa光诱导片段切割位点的区域。D2的显著降解仅在电子受体存在时发生，并且丝氨酸型蛋白酶抑制剂可部分阻止该蛋白的降解。
