Department of Regulation Biology, National Institute for Basic Biology, 444, Okazaki, Japan.
Photosynth Res. 1993 Apr;36(1):35-42. doi: 10.1007/BF00018073.
In order to identify the domain within Photosystem II complexes that functions in the evolution of oxygen, we performed limited proteolysis with lysylendopeptidase of the core complex of Photosystem II which had been depleted of the extrinsic 33-kDa protein (Mn-stabilizing protein). The cleavage sites were estimated from the amino-terminal sequences of the degradation fragments, their apparent molecular masses and amino-acid compositions. Under certain conditions, the D2 protein was cleaved at Lys13; and a chlorophyll a-binding protein, CP 47, was cleaved at Lys227 and Lys389. Another chlorophyll a-binding protein, CP 43, was degraded more rapidly than CP 47. The oxygen-evolving activity and the capacity for rebinding of the 33-kDa protein to the core complex of Photosystem II decreased in parallel, with kinetics very similar to those of the cleavage of CP 47 at Lys389. These observations strongly suggest that the hydrophilic domain around Lys389 of CP 47, which are located on the lumenal side, is important in the binding of the 33-kDa protein and in maintaining the oxygen-evolving activity of the Photosystem II complex.
为了确定在光合系统 II 复合物中与氧气进化功能相关的结构域，我们使用赖氨酰内肽酶对已耗尽了外周 33kDa 蛋白（Mn 稳定蛋白）的光合系统 II 核心复合物进行了有限的蛋白水解。通过降解片段的氨基末端序列、它们的表观分子量和氨基酸组成来估计切割位点。在某些条件下，D2 蛋白在赖氨酸 13 处被切割；叶绿素 a 结合蛋白 CP47 在赖氨酸 227 和赖氨酸 389 处被切割。另一个叶绿素 a 结合蛋白 CP43 比 CP47 降解得更快。产氧活性和 33kDa 蛋白与光合系统 II 核心复合物的重新结合能力平行下降，其动力学与 CP47 在赖氨酸 389 处的裂解非常相似。这些观察结果强烈表明，位于腔侧的 CP47 上赖氨酸 389 周围的亲水区对于 33kDa 蛋白的结合和维持光合系统 II 复合物的产氧活性非常重要。
