Study of the Hansenula anomala yeast flavocytochrome-b2-cytochrome-c complex 2. Localization of the main association area.
Study of the Hansenula anomala yeast flavocytochrome-b2-cytochrome-c complex 2. Localization of the main association area.
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异常汉逊酵母黄素细胞色素-b2-细胞色素-c复合物的研究2.主要关联区域的定位。
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发表时间：
1983
期刊：
影响因子：
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通讯作者：
Pierre Valat
中科院分区：
文献类型：
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作者：
Marie;Michel Gervais;Vincent Favaudon;Pierre Valat
Zn2+ 取代的异常汉逊酵母细胞色素 c 二聚体（Thomas 等人，本期前一篇文章）与氧化或乳酸还原状态的黄素细胞色素 b2 的可逆关联已通过荧光测定法进行了研究。相同的方法已用于测定与确定的黄素细胞色素 b2 蛋白水解片段（含血红素 b2 的单体或黄素连接的四聚体）复合的 Zn-细胞色素 c 复合物。除分离的细胞色素 b2 核心外，所有这些片段均显示出与天然黄素细胞色素 b2 中发现的结合化学计量、Kd 值和离子强度依赖性非常相似。这些数据允许将细胞色素c的单个高亲和力结合位点定位在黄素细胞色素b2原聚体的脱氢酶结构域中的特定小球上。各种复合物中 Zn-卟啉 c 荧光的猝灭仅伴随着荧光寿命的微小变化，并且与血红素 b2 基团的存在或氧化还原状态没有任何直接关系。
The reversible association of the Zn2+-substituted Hansenula anomala cytochrome c dimer (Thomas et al., preceding paper in this issue) to flavocytochrome b2 in oxidized or lactate-reduced state has been investigated by fluorimetry. The same method has been used for the determination of Zn-cytochrome c complexing to defined proteolytic fragments of flavocytochrome b2, either heme-b2-containing monomers or a flavin-linked tetramer. All these fragments but the isolated cytochrome b2 core showed binding stoichiometries, Kd values and ionic strength dependences quite similar to those found for native flavocytochrome b2. These data allowed localization of the single high-affinity binding site of cytochrome c on a particular globule in the dehydrogenase domain of the flavocytochrome b2 protomers. Quenching of the Zn-porphyrin c fluorescence in the various complexes occurred with only minor changes of the fluorescence lifetime and did not show any direct relationship to the presence or the redox state of the heme b2 group.