Lin L, Pinker R J, Forde K, Rose G D, Kallenbach N R
Department of Chemistry, New York University, New York 10003, USA.
Nat Struct Biol. 1994 Jul;1(7):447-52. doi: 10.1038/nsb0794-447.
Apomyoglobin, myoglobin lacking the haem group, is a natural intermediate in biosynthesis of myoglobin, and has some structural features in common with the haem-containing native state. Unfolding or refolding studies of apomyoglobin have identified a molten globule intermediate at acid pH. We show here that both the native state of apomyoglobin and the molten globule intermediate have highly plastic structures. Substitution of single amino acids on the surface or in the interior of helices in the native protein produce dramatic changes in the helix content and tryptophan emission of apomyoglobin at neutral and acidic pH. The signals from the intermediate and native apomyoglobin correlate closely suggesting that apomyoglobin itself has a molten globule-like character, its structure representing a population of interconverting substates rather than a fixed conformation.
脱辅基肌红蛋白是缺乏血红素基团的肌红蛋白，是肌红蛋白生物合成中的天然中间体，并且具有一些与含血红素的天然状态相同的结构特征。对脱辅基肌红蛋白的去折叠或重折叠研究已确定在酸性pH下存在熔球中间体。我们在此表明，脱辅基肌红蛋白的天然状态和熔球中间体都具有高度可塑性的结构。在天然蛋白质的螺旋表面或内部单个氨基酸的取代会在中性和酸性pH下使脱辅基肌红蛋白的螺旋含量和色氨酸发射产生显著变化。来自中间体和天然脱辅基肌红蛋白的信号密切相关，这表明脱辅基肌红蛋白本身具有类似熔球的特征，其结构代表了一组相互转化的亚状态，而不是固定的构象。
Zotero 插件