Organization of Photosystem I Polypeptides (A Structural Interaction between the PsaD and PsaL Subunits)
Organization of Photosystem I Polypeptides (A Structural Interaction between the PsaD and PsaL Subunits)
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DOI：
10.1104/pp.106.3.1057
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发表时间：
1994-11
期刊：
影响因子：
--
通讯作者：
Q. Xu;T. Armbrust;J. Guikema;P. Chitnis
中科院分区：
文献类型：
--
作者：
Q. Xu;T. Armbrust;J. Guikema;P. Chitnis
蓝藻集胞藻属的野生型、PsaD-less 和 PsaL-less 菌株。 PCC 6803 用于研究光系统 I (PSI) 中的亚基相互作用。当用 Triton X-100 溶解不含 PsaD 的菌株的膜，并使用离子交换色谱和蔗糖梯度超速离心纯化 PSI 时，PsaL 亚基基本上从 PSI 的核心去除，而其他亚基（例如 PsaE 和 PsaF）在纯化过程中被定量保留。当野生型 PSI 暴露于浓度不断增加的 NaI 时，PsaE、PsaD 和 PsaC 亚基逐渐被去除，而 PsaF、PsaL、PsaK 和 PsaJ 则可抵抗高达 3 M NaI 的去除。 PsaL 的缺失增强了 PsaD 被 NaI 去除的可能性。在4℃下用戊二醛处理野生型PSI复合物产生PsaD和PsaL之间的29-kD交联产物。这种交联物质的形成与 PSI 浓度无关，表明 PsaD 和 PsaL 之间存在复合物内交联。总而言之，这些结果证明了 PsaD 和 PsaL 之间的结构相互作用，在它们与 PSI 核心的关联中发挥了作用。
The wild-type, PsaD-less, and PsaL-less strains of the cyanobacterium Synechocystis sp. PCC 6803 were used to study subunit interactions in photosystem I (PSI). When the membranes of a PsaD-less strain were solubilized with Triton X-100 and PSI was purified using ion-exchange chromatography and sucrose-gradient ultracentrifugation, the PsaL subunit was substantially removed from the core of PSI, whereas other subunits, such as PsaE and PsaF, were quantitatively retained during purification. When the wild-type PSI was exposed to increasing concentrations of NaI, the PsaE, PsaD, and PsaC subunits were gradually removed, whereas PsaF, PsaL, PsaK, and PsaJ resisted removal by up to 3 M NaI. The absence of PsaL enhanced the accessibility of PsaD to removal by NaI. Treatment of the wild-type PSI complexes with glutaraldehyde at 4[deg] C resulted in a 29-kD cross-linked product between PsaD and PsaL. The formation of such cross-linked species was independent of PSI concentrations, suggesting an intracomplex cross-linking between PsaD and PsaL. Taken together, these results demonstrate a structural interaction between PsaD and PsaL that plays a role in their association with the PSI core.