Characterisation of the LH2 spectral variants produced by the photosynthetic purple sulphur bacterium Allochromatium vinosum
Characterisation of the LH2 spectral variants produced by the photosynthetic purple sulphur bacterium Allochromatium vinosum
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DOI：
10.1016/j.bbabio.2014.07.022
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发表时间：
2014-11-01
影响因子：
4.3
通讯作者：
Cogdell, Richard J.
中科院分区：
文献类型：
--
作者：
Carey, Anne-Marie;Hacking, Kirsty;Cogdell, Richard J.
这项研究系统地研究了 Allochromatium (Ala) vinosum（一种光合紫色硫细菌）产生的不同类型的 LH2，以响应生长条件的变化。分离和纯化了三种不同光谱形式的 LH2，即 B800-820、B800-840 和 B800-850 LH2 类型，所有这些类型在低温吸收光谱中都表现出不寻常的分裂 800 峰。然而，很可能还存在更多形式。在弱光条件下产生相对较多的B800-820和0800-840，而在高光条件下产生相对较多的B800-850。通过 HPLC 和 TOF/MS 的组合测定三种不同 LH2 类型的多肽组成。 B800-820、B800-840和B800-850 LH2类型均具有异质多肽组成，含有多种类型的α和β多肽，并且其精确的多肽组成不同。它们都具有混合类胡萝卜素成分，含有螺菌黄素系列的类胡萝卜素。在所有情况下，最丰富的类胡萝卜素是视紫红质。然而，在弱光条件下产生的 LH2 复合物中出现了向具有更高共轭数的类胡萝卜素的转变。 CD 光谱与多肽分析一起表明这些 Alc。 vinosum LH2 复合物与 Phs 中的 LH2 复合物关系更密切。 molischianum 比它们从 Rps 到 LH2 复合物的作用更大。嗜酸菌。 (C) 2014 年由 Elsevier B.V. 出版
This study systematically investigated the different types of LH2 produced by Allochromatium (Ala) vinosum, a photosynthetic purple sulphur bacterium, in response to variations in growth conditions. Three different spectral forms of LH2 were isolated and purified, the B800-820, B800-840 and B800-850 LH2 types, all of which exhibit an unusual split 800 peak in their low temperature absorption spectra. However, it is likely that more forms are also present. Relatively more B800-820 and 0800-840 are produced under low light conditions, while relatively more B800-850 is produced under high light conditions. Polypeptide compositions of the three different LH2 types were determined by a combination of HPLC and TOF/MS. The B800-820, B800-840 and B800-850 LH2 types all have a heterogeneous polypeptide composition, containing multiple types of both alpha and beta polypeptides, and differ in their precise polypeptide composition. They all have a mixed carotenoid composition, containing carotenoids of the spirilloxanthin series. In all cases the most abundant carotenoid is rhodopin; however, there is a shift towards carotenoids with a higher conjugation number in LH2 complexes produced under low light conditions. CD spectroscopy, together with the polypeptide analysis, demonstrates that these Alc. vinosum LH2 complexes are more closely related to the LH2 complex from Phs. molischianum than they are to the LH2 complexes from Rps. acidophila. (C) 2014 Published by Elsevier B.V.