Smith S O, Song D, Shekar S, Groesbeek M, Ziliox M, Aimoto S
Department of Biochemistry and Cell Biology, Center for Structural Biology, State University of New York at Stony Brook, 11794-5115, USA.
Biochemistry. 2001 Jun 5;40(22):6553-8. doi: 10.1021/bi010357v.
The hydrophobic transmembrane domain of glycophorin A contains a sequence motif that mediates dimerization in membrane environments. Long-range interhelical distance measurements using magic angle spinning NMR spectroscopy provide high-resolution structural constraints on the packing of the dimer interface in membrane bilayers. We show that direct packing contacts occur between glycine residues at positions 79 and 83 in the transmembrane sequence. Additional interhelical constraints between Ile76 and Gly79 and between Val80 and Gly83 restrict the rotational orientation and crossing angle of the interacting helices. These results refine our previously proposed structure of the glycophorin A dimer [Smith, S. O., and Bormann, B. J. (1995) Proc. Natl. Acad. Sci. U.S.A. 92, 488-491] which revealed that the methyl groups of Val80 and Val84 are packed against Gly79 and Gly83, respectively.
血型糖蛋白A的疏水跨膜结构域包含一个在膜环境中介导二聚化的序列基序。使用魔角旋转核磁共振光谱进行的远程螺旋间距离测量为膜双层中二聚体界面的堆积提供了高分辨率的结构限制。我们表明，跨膜序列中第79位和第83位的甘氨酸残基之间存在直接堆积接触。Ile76与Gly79之间以及Val80与Gly83之间的额外螺旋间限制限制了相互作用螺旋的旋转取向和交叉角度。这些结果完善了我们之前提出的血型糖蛋白A二聚体结构[史密斯，S.O.，和博尔曼，B.J.（1995年）《美国国家科学院院刊》92，488 - 491]，该结构表明Val80和Val84的甲基分别与Gly79和Gly83堆积在一起。
