The structure and thermal motion of the B800-850 LH2 complex from Rps. acidophila at 2.0 (A)over-circle resolution and 100 K:: New structural features and functionally relevant motions
The structure and thermal motion of the B800-850 LH2 complex from Rps. acidophila at 2.0 (A)over-circle resolution and 100 K:: New structural features and functionally relevant motions
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DOI：
10.1016/s0022-2836(03)00024-x
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发表时间：
2003-03-07
影响因子：
5.6
通讯作者：
Isaacs, NW
中科院分区：
文献类型：
--
作者：
Papiz, MZ;Prince, SM;Isaacs, NW
在100 K的结构的完整的膜捕光复合物11（LH 2）从嗜酸红球藻菌株10050已被细化到2.0埃分辨率。与2.5埃分辨率图相比，通过高分辨率数据、低温冷却和平移、天平动、螺旋（TLS）细化，plectron密度已得到显著改善。电子密度揭示了第二类胡萝卜素分子，α链的最后五个C-末端残基和羧基修饰的α-Met 1，其形成B800细菌叶绿素的配体。TLS的完善，使复杂的分子之间的位移的特性。B850细菌叶绿素分子排列在由9个近似二聚体组成的18个色素环中。这些色素是强耦合的，在它们的平衡位置，二聚体内部和二聚体之间的激发态偶极相互作用能分别为370 cm（-1）和280 cm（-1）。这种耦合能的差异在幅度上类似于由TLS张量描述的色素位移引起的相互作用能的变化。位移在本质上似乎是非随机的，并且似乎被设计为优化色素能量相互作用的调制。这是第一次通过实验对LH 2色素位移进行量化。计算的能量变化表明，可能有显着的贡献色素间的能量相互作用的分子位移，这些可能是重要的光合能量转移。(C)2003爱思唯尔科技有限公司版权所有。
The structure at 100 K of integral membrane light-harvesting complex 11 (LH2) from Rhodopseudomonas acidophila strain 10050 has been refined to 2.0 Angstrom resolution. The plectron density has been significantly improved, compared to the 2.5 Angstrom resolution map, by high resolution data, cryo-cooling and translation, libration, screw (TLS) refinement. The electron density reveals a second carotenoid molecule, the last five C-terminal residues of the alpha-chain and a carboxy modified alpha-Met1 which forms the ligand of the B800 bacteriochlorophyll. TLS refinement has enabled the characterisation of displacements between molecules in the complex. B850 bacteriochlorophyll molecules are arranged in a ring of 18 pigments composed of nine approximate dimers. These pigments are strongly coupled and at their equilibrium positions the excited state dipole interaction energies, within and between dimers, are similar to370 cm(-1) and 280 cm(-1), respectively. This difference in coupling energy is similar in magnitude to changes in interaction energies arising from the pigment displacements described by TLS tensors. The displacements appear to be non-random in nature and appear to be designed to optimise the modulation of pigment energy interactions. This is the first time that LH2 pigment displacements have been quantified experimentally. The calculated energy changes indicate that there may be significant contributions to inter-pigment energy interactions from molecular displacements and these may be of importance to photosynthetic energy transfer. (C) 2003 Elsevier Science Ltd. All rights reserved.