Smith S O, Bormann B J
Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520-8114.
Proc Natl Acad Sci U S A. 1995 Jan 17;92(2):488-91. doi: 10.1073/pnas.92.2.488.
Dimerization of human glycophorin A in erythrocyte membranes is mediated by specific interactions within the helical transmembrane domain of the protein. Rotational resonance NMR provides a unique approach for obtaining high-resolution structural data in membrane systems and has been used to establish intermolecular contacts in the glycophorin A dimer by using hydrophobic peptides that correspond to the transmembrane sequence. Magnetization exchange rates were measured between [13C]methyl labels in the hydrophobic sequence -G79-V80-M81-A82-G83-V84- located in the middle of the transmembrane domain and specific [13C]carbonyl labels along the peptide backbone across the dimer interface. Significant magnetization exchange was observed only between V80 (13CH3) and G79 (13C = O) and between V84 (13CH3) and G83 (13C = O), indicating that these residues are packed in the dimer interface in a "ridges-ingrooves" arrangement.
人红细胞膜上血型糖蛋白A的二聚化是由该蛋白螺旋跨膜结构域内的特异性相互作用介导的。旋转共振核磁共振为在膜系统中获取高分辨率结构数据提供了一种独特的方法，并且已被用于通过使用与跨膜序列相对应的疏水肽来确定血型糖蛋白A二聚体中的分子间接触。在位于跨膜结构域中部的疏水序列-G79-V80-M81-A82-G83-V84-中的[13C]甲基标记与沿着肽主链穿过二聚体界面的特定[13C]羰基标记之间测量了磁化交换率。仅在V80（13CH3）与G79（13C = O）之间以及V84（13CH3）与G83（13C = O）之间观察到显著的磁化交换，表明这些残基以“脊-槽”排列堆积在二聚体界面中。
