Huo S, Arumugam S, Cross T A
Department of Chemistry, Florida State University, Tallahassee 32306-4005, USA.
Solid State Nucl Magn Reson. 1996 Dec;7(3):177-83. doi: 10.1016/s0926-2040(96)01260-x.
Hydrogen exchange experiments for a membrane-bound polypeptide could lead to interesting functional and structural insights. Here, hydrogen/deuterium exchange, saturation transfer and differential relaxation experiments have been performed on oriented lipid bilayer-bound polypeptide samples to measure the exchange lifetimes. The polypeptide, gramicidin A, forms a monovalent cation selective channel across membranes. The pH dependent results suggest that the indole N epsilon 1-H groups show base catalyzed hydrogen exchange, but that the backbone amide sites are not base catalyzed, consistent with the exclusion of anions from this channel. Furthermore, the recently described [1] orientational distribution of the individual peptide carbonyls (i.e. carbonyls either tipped slightly in toward or away from the channel axis) is consistent with the observed difference in odd- and even-numbered amide residue exchange lifetimes.
对膜结合多肽进行氢交换实验可能会带来有趣的功能和结构方面的见解。在此，已对定向脂质双层结合的多肽样品进行了氢/氘交换、饱和转移和差异弛豫实验，以测量交换寿命。多肽短杆菌肽A形成跨膜的单价阳离子选择性通道。pH依赖性结果表明，吲哚Nε1-H基团显示出碱催化的氢交换，但主链酰胺位点不是碱催化的，这与该通道中阴离子的排除一致。此外，最近描述的[1]各个肽羰基的取向分布（即羰基要么稍微向通道轴倾斜要么远离通道轴）与观察到的奇数和偶数酰胺残基交换寿命的差异一致。
