Statistical considerations on the formation of circular photosynthetic light-harvesting complexes from Rhodopseudomonas palustris.
Statistical considerations on the formation of circular photosynthetic light-harvesting complexes from Rhodopseudomonas palustris.
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关于沼泽红假单胞菌圆形光合光捕获复合物形成的统计考虑。
DOI：
10.1007/s11120-014-9975-x
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发表时间：
2014
影响因子：
3.7
通讯作者：
Taniguchi M
中科院分区：
文献类型：
--
作者：
Taniguchi M
根据生长条件的不同，某些紫色光合细菌含有外周捕光（LH 2）复合物，由于存在不同的原体（含有不同的αβ-脱辅基蛋白），这些复合物是异质的。最近的光谱研究表明，Rhodopalyptuspalustris生长在低光条件下的存在下，C3-对称的LH 2九聚体组成的两个不同的原聚体。软件程序Cyclaplex，它能够生成和数据挖掘的虚拟库的分子环上形成的组合反应，已被用来描绘可能的数量和类型的不同的九聚体作为一个功能的不同的原聚体的数量。在下列条件下研究了由两个原聚体（A和B以不同的比例）合成C3-对称九聚体的产率：（1）统计学，（2）富集（排除B-B序列），和（3）接种（预先形成A-B-A嵌段）。在统计条件下，C3-对称九聚体的产率为至多0.98%，而在富集条件下为5.6%，并且在用A-B-A嵌段预接种的条件下可以占主导地位。总之，任何一个特定的九聚体的形成，即使从只有两个原聚体是不可能的统计理由，但必须源于增强的自由能的形成或定向组装过程中的未知因素。
Depending on growth conditions, some species of purple photosynthetic bacteria contain peripheral light-harvesting (LH2) complexes that are heterogeneous owing to the presence of different protomers (containing different αβ-apoproteins). Recent spectroscopic studies ofRhodopseudomonas palustrisgrown under low-light conditions suggest the presence of aC3-symmetric LH2 nonamer comprised of two distinct protomers. The software programCyclaplex, which enables generation and data-mining of virtual libraries of molecular rings formed upon combinatorial reactions, has been used to delineate the possible number and type of distinct nonamers as a function of numbers of distinct protomers. The yield of theC3-symmetric nonamer from two protomers (A and B in varying ratios) has been studied under the following conditions: (1) statistical, (2) enriched (preclusion of the B-B sequence), and (3) seeded (pre-formation of an A-B-A block). The yield ofC3-symmetric nonamer is at most 0.98 % under statistical conditions versus 5.6 % under enriched conditions, and can be dominant under conditions of pre-seeding with an A-B-A block. In summary, the formation of any one specific nonamer even from only two protomers is unlikely on statistical grounds but must stem from enhanced free energy of formation or a directed assembly process by as-yet unknown factors.