Internal and external membrane proteins of the cyanobacterium, Synechococcus cedrorum.
Internal and external membrane proteins of the cyanobacterium, Synechococcus cedrorum.
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蓝藻、雪松聚球藻的内膜和外膜蛋白。
DOI：
10.1016/0005-2736(81)90556-3
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发表时间：
1981
期刊：
影响因子：
--
通讯作者：
Sherman,LA
中科院分区：
文献类型：
--
作者：
Sadewasser,DA;Sherman,LA
借助位点特异性标记，分析了蓝藻雪松聚球藻光合膜的蛋白质组成和结构。使用35S标记的膜，通过十二烷基硫酸钠丙烯酰胺凝胶电泳可以检测约50种膜蛋白。大约一半的蛋白质可以被不渗透探针乳过氧化物酶修饰，表明它们具有表面暴露的结构域。这些外部蛋白质中至少有六种可以通过 EDTA 洗涤去除；这些 EDTA 可提取蛋白质中的五种与典型叶绿体偶联因子制剂之间的分子量对应关系可能表明它们是膜结合 ATP 酶的亚基。光活性亲脂性化合物[125I]碘萘基叠氮化物用于标记与脂质双层接触的蛋白质结构域。碘萘基叠氮化物修饰导致标记模式与乳过氧化物酶观察到的标记模式显着不同。特别是，乳过氧化物酶标记效果较差或根本没有标记的 13 000–20 000 道尔顿范围内的蛋白质被碘代萘基叠氮化物大量修饰。通过洋地黄皂苷处理从膜中提取的光系统 I 和 II 颗粒在分离后被乳过氧化物酶碘化。 PS I 颗粒充当相对紧密的复合物，大多数蛋白质仍然无法进行表面修饰。另一方面，PS II 颗粒的反应为更开放的结构，大多数亚基可被乳过氧化物酶碘化。对 S 的高荧光、温度敏感突变体进行了类似的研究。雪松揭示了 PS II 复合体的不同组织。该突变体在 40°C 下生长时，会插入 51 kdalton 多肽代替 53 kdalton 蛋白质。在 40°C 生长后，该蛋白质还取代了突变体 PS II 复合物中的 53 kdalton 物质。该复合物的结构发生了改变，乳过氧化物酶可接近更多位点。对于 51 kdalton 蛋白质尤其如此，该蛋白质在野生型 PS II 复合物中几乎没有被标记。
The protein composition and architecture of the photosynthetic membranes from the cyanobacterium,Synechococcus cedrorum, were analyzed with the aid of site-specific labels. Using membranes labeled with35S, about 50 membrane proteins can be detected by sodium dodecyl sulfate acrylamide gel electrophoresis. Approximately half of the proteins are accessible to modification by the impermeant probe, lactoperoxidase, indicating that they have surface-exposed domains. At least six of these external proteins can be removed by EDTA washing; the correspondence in molecular weights between five of these EDTA-extractable proteins and those of typical chloroplast coupling factor preparations may indicate that they are subunits of a membrane-bound ATPase. The photoactive, lipophilic compound, [125I]iodonaphthyl azide, was used to label protein domains in contact with the lipid bilayer. Iodonaphthyl azide modification led to a labeling pattern significantly different from that seen with lactoperoxidase. In particular, proteins in the 13 000–20 000 dalton range that were labeled poorly or not at all by lactoperoxidase were heavily modified by iodonaphthyl azide.Photosystem I and II particles, extracted from the membrane by digitonin treatment, were iodinated by lactoperoxidase after isolation. The PS I particles acted as a relatively tight complex, with most of the proteins remaining inaccessible to surface modification. The PS II particles, on the other hand, responded as a more open structure, with most of the subunits yielding to lactoperoxidase iodination. Similar studies on a highly fluorescent, temperature-sensitive mutant ofS. cedrorumrevealed a different organization of the PS II complex. This mutant, when grown at 40°C, inserts a 51 kdalton polypeptide in place of a 53 kdalton protein. This protein also replaces the 53 kdalton species in the PS II complex of the mutant after 40°C growth. The structure of this complex is altered in that more sites become accessible to lactoperoxidase. This is particularly true of the 51 kdalton protein, which is barely labeled in wild-type PS II complexes.