蛋白质折叠子的功能作用——一种Ω环折叠子控制细胞色素c中铁离子的碱性转变。
Functional role of a protein foldon--an Omega-loop foldon controls the alkaline transition in ferricytochrome c.
作者信息
Maity Haripada, Rumbley Jon N, Englander S Walter
机构信息
The Johnson Research Foundation, Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA.
出版信息
Proteins. 2006 May 1;63(2):349-55. doi: 10.1002/prot.20757.
Hydrogen exchange results for cytochrome c and several other proteins show that they are composed of a number of foldon units which continually unfold and refold and account for some functional properties. Previous work showed that one Omega-loop foldon controls the rate of the structural switching and ligand exchange behavior of cytochrome c known as the alkaline transition. The present work tests the role of foldons in the alkaline transition equilibrium. We measured the effects of denaturant and 14 destabilizing mutations. The results show that the ligand exchange equilibrium is controlled by the stability of the same foldon unit implicated before. In addition, the results obtained confirm the epsilon-amino group of Lys79 and Lys73 as the alkaline replacement ligands and bear on the search for a triggering group.
细胞色素c和其他几种蛋白质的氢交换结果表明，它们由许多折叠子单元组成，这些单元不断地展开和重新折叠，并解释了一些功能特性。先前的研究表明，一个Ω-环折叠子控制着细胞色素c的结构转换速率和配体交换行为，即碱性转变。目前的工作测试了折叠子在碱性转变平衡中的作用。我们测量了变性剂和14个不稳定突变的影响。结果表明，配体交换平衡受之前涉及的相同折叠子单元稳定性的控制。此外，所得结果证实了赖氨酸79和赖氨酸73的ε-氨基作为碱性替代配体，并有助于寻找触发基团。
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