Dempsey C E, Butler G S
Department of Biochemistry, Bristol University, England.
Biochemistry. 1992 Dec 8;31(48):11973-7. doi: 10.1021/bi00163a003.
A trapping method combined with high-resolution nuclear magnetic resonance spectroscopy is described for the measurement of hydrogen-deuterium exchange rates for individual amides of polypeptides bound to fully hydrated, dispersed phospholipid bilayers. Exchange rates were measured for 22 of the 24 amide hydrogens of bee venom melittin bound to bilayers composed of egg phosphatidylcholine/phosphatidylserine (88:12, mol/mol) dispersed in 20 mM sodium acetate, pH 4.0. Amides of residues 5-11 and 16-22 had exchange rates suppressed by between 30- and 1000-fold, and the rate suppression exhibited a helical periodicity with amides on the hydrophobic helix face up to 20-fold more stable than those on the hydrophilic face of the helix. These results demonstrate that under the conditions studied melittin adopts a helical conformation with stable helical hydrogen bonds extending to residue 22 and that the helix is oriented with the hydrophobic face directed toward the membrane interior.
本文描述了一种结合高分辨率核磁共振光谱的捕获方法，用于测量与完全水合的分散磷脂双层结合的多肽单个酰胺的氢-氘交换率。测量了与分散在20 mM醋酸钠（pH 4.0）中的鸡蛋磷脂酰胆碱/磷脂酰丝氨酸（88:12，摩尔/摩尔）组成的双层结合的蜂毒溶血素24个酰胺氢中的22个的交换率。5-11和16-22位残基的酰胺交换率被抑制了30至1000倍，并且速率抑制呈现螺旋周期性，疏水性螺旋面上的酰胺比螺旋亲水性面上的酰胺稳定高达20倍。这些结果表明，在所研究的条件下，溶血素采用螺旋构象，稳定的螺旋氢键延伸至22位残基，并且螺旋的取向是疏水面朝向膜内部。
