The structure of chloroplast cytochrome c6 at 1.9 A resolution: evidence for functional oligomerization.
The structure of chloroplast cytochrome c6 at 1.9 A resolution: evidence for functional oligomerization.
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1.9 A 分辨率下叶绿体细胞色素 c6 的结构：功能性寡聚化的证据。
DOI：
10.1006/jmbi.1995.0404
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
Yeates,TO
中科院分区：
文献类型：
--
作者：
Kerfeld,CA;Anwar,HP;Interrante,R;Merchant,S;Yeates,TO
测定了莱氏绿色藻细胞色素6的两种晶型的分子结构，并将其分辨率提高到1.9 μ m。这两种晶体形式可能是蛋白质翻译后修饰水平不同的结果。这是第一个报告的高分辨率结构的叶绿体衍生类Ic型细胞色素。整体折叠与其他Ic类细胞色素相似，由一系列α-螺旋和转角组成，包裹血红素辅基。在血红素的蛋氨酸轴向配体附近也有一个短的双链反平行β折叠;分子的这个区域由6型细胞色素中最高度保守的残基形成。虽然Ic类细胞色素被认为是单体，但两种晶体形式的细胞色素6都表现出血红素裂隙周围的寡聚化，这部分是由短的自平行β折叠介导的。这种低聚反应的功能意义是支持在其他电子转移夫妇的类似接口的外观。HPLC和光散射数据，并且进一步与c6型细胞色素的电子转移反应的动力学数据一致。
The molecular structure of cytochromec6from the green algaChlamydomonas reinhardtiihas been determined from two crystal forms and refined to 1.9 Å resolution. The two crystal forms are likely the result of different levels of post-translational modification of the protein. This is the first report of a high-resolution structure of a chloroplast-derived class Ic-type cytochrome. The overall fold is similar to that of other class Ic-type cytochromes, consisting of a series of α-helices and turns that envelop the heme prosthetic group. There is also a short two-stranded anti-parallel β-sheet in the vicinity of the methionine axial ligand to the heme; this region of the molecule is formed by the most highly conserved residues inc6-type cytochromes. Although class Ic-type cytochromes are assumed to function as monomers, both crystal forms of cytochromec6exhibit oligomerization about the heme crevice that is, in part, mediated by the short anto-parallel β-sheet. The functional significance of this oligomerization is supported by the appearance of similar interfaces in other electron transfer couples. HPLC and light-scattering data, and is furthermore consistent with kinetic data on electron transfer reactions ofc6-type cytochromes.f2