Comparison of the structural requirements for bacteriochlorophyll binding in the core light-harvesting complexes of Rhodospirillum rubrum and Rhodobacter sphaeroides using reconstitution methodology with bacteriochlorophyll analogs
Comparison of the structural requirements for bacteriochlorophyll binding in the core light-harvesting complexes of Rhodospirillum rubrum and Rhodobacter sphaeroides using reconstitution methodology with bacteriochlorophyll analogs
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DOI：
10.1021/bi951777l
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发表时间：
1996-03-05
期刊：
影响因子：
2.9
通讯作者：
Loach, PA
中科院分区：
文献类型：
--
作者：
Davis, CM;ParkesLoach, PS;Loach, PA
通过用 BChl 类似物以及红螺菌属和球形红杆菌的 α 和 β 多肽重建来检查细菌叶绿素 (BChl) 形成核心光捕获复合物 (LH1) 及其结构亚基复合物的结构要求。用大多数BChl类似物和每种细菌的多肽获得了可比较的结果，表明BChl结合位点的保守性。这些系统显示了形成亚基复合物和 LH1 的以下共同要求：（1） Mg 或类似尺寸和配位化学的金属油（例如 Zn、Cd、Ni），（2） 大环的菌绿素氧化态，（3） 13（2）-甲甲氧基基团，以及（4）完整的环 V。一些结构特征至关重要。例如，可以形成亚基复合物和 LH1与两组多肽和BChl b，以及含有短（乙醇）或长（植醇）酯化醇的类似物相比，鉴定出两种衍生物，其与两组多肽表现不同。尽管 [3-乙烯基]BChl cc 和 Rs 的多肽很容易形成亚基型复合物，但在两种细菌中形成 LH1 都需要 3-乙酰基。 rubrum，但在特殊条件下仅与 Rb 的多肽轻微形成。球状体。 [13(2)-OH]BChl a(p)与Rb的α-和β-多肽形成亚基型和LH1型复合物。 sphaeroides，但不包括Rs、rubrum。因此，这两种细菌的 LH1 复合物中的 BChl 结合位点存在一些细微的差异。
Bacteriochlorophyll (BChl) structural requirements for formation of the core light-harvesting complex (LH1) and its structural subunit complex were examined by reconstitution with BChl analogs and the alpha- and beta-polypeptides of Rhodospirillum and Rhodobacter sphaeroides. Comparable results were obtained with most of the BChl analogs and the polypeptides of each bacterium, indicating the conservation of BChl binding sites. These systems showed the following common requirements for formation of the subunit complex and LH1: (1) Mg or a metal oil similar size and coordination chemistry (e.g., Zn, Cd, Ni), (2) a bacteriochlorin oxidation state of the macrocyclic ring, (3) a 13(2)-carbomethoxy group, and (4) an intact ring V. Some structural features were riot as critically important., For example, the subunit complex and LH1 could be formed with both sets of polypeptides and BChl b, as well as with analogs containing either short (ethanol) or long (phytol) esterifying alcohols, Two derivatives were identified that behave differently with the two sets of polypeptides. The 3-acetyl group is required to form LH1 in both bacteria, although a subunit-type complex was readily formed with [3-vinyl]BChl cc and the polypeptides of Rs. rubrum but formed only slightly under special conditions with polypeptides of Rb. sphaeroides. [13(2)-OH]BChl a(p) formed both subunit- and LH1-type complexes with the alpha- and beta-polypeptides of Rb. sphaeroides but not with those of Rs, rubrum. Thus, some subtle differences in the BChl binding sites exist in the LH1 complexes of these two bacteria.