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NMR Study of Structural and Dynamic Properties of Paramagnetic Proteins ,

顺磁性蛋白质的结构和动态特性的核磁共振研究，

基本信息

批准号：
9104018
负责人：
Gerd La Mar
金额：
$ 27万
依托单位：
University of California-Davis
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
1991
资助国家：
美国
起止时间：
1991-11-01 至 1995-10-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=9104018&HistoricalAwards=false
关键词：
NMR Study Structural Dynamic Properties

项目摘要

Nuclear magnetic resonance studies of a variety of paramagnetic metalloproteins are proposed in order to extract unique electronic/molecular structural information from the hyperfine shifts as relevant to the formation of ligation channels in proteins, the control of redox potential of electron mediators, and the detection of intermediates in the unfolding of proteins. Central to all of these studies is the development and implementation of two-dimensional NMR strategies, that will provide the critical assignments for the paramagnetically relaxed, broadened and shifted resonances. Changes in labile proton exchange rates upon mutation/chemical modification in the distal heme pocket of cyano-metmyoblobin will be used to define the interactions that allows formation of a transient ligation channel to the heme pocket. The influence of heme orientation and hydrogen bonding by an axial histidine on heme electronic structure will be elucidated for cytochrome b5, and the origins of the pKs that modulate the redox potential of cytochrome b562 will be identified. The contact shifted resonance of bound cysteines in a variety of iron-sulfur cluster electron mediators will be assigned to specific residues in the protein sequence, and the valence states of individual irons in the cluster will be interpreted on the basis of available X-ray crystal structure to elucidate the mechanism of protein control of localized iron redox potential. The heme and axial histidine resonances of high-spin ferricytochromes c' will be assigned to interpret the nature of the equilibrium pre-transition structural changes detected during reversible thermal unfolding.

核磁共振研究了各种顺磁金属蛋白被提出，以提取独特的电子/分子结构信息从超精细与连接通道的形成相关的转移，蛋白质，电子介质氧化还原电位的控制，以及检测解折叠过程中的中间体 proteins. 所有这些研究的核心是发展和实施二维核磁共振战略，这将提供顺磁性的临界分配放松，扩大和转移共振。不稳定的变化突变/化学修饰后的质子交换率氰基-甲肌球蛋白的远端血红素袋将用于定义允许瞬态形成的相互作用连接通道到血红素口袋。血红素的影响通过血红素上的轴向组氨酸的取向和氢键将阐明细胞色素b5的电子结构，调节氧化还原电位的pKs的来源将鉴定细胞色素b562。触点移动了各种铁硫中结合半胱氨酸的共振簇电子介质将被分配到特定的蛋白质序列中的残基，以及集群中的单个熨斗将在根据现有的X射线晶体结构来阐明蛋白质控制局部铁氧化还原电位的机制。高自旋的血红素和轴向组氨酸共振铁细胞色素c'将被分配来解释所检测到的平衡过渡前结构变化在可逆的热解折叠过程中。