Chen L Q, Rose J P, Breslow E, Yang D, Chang W R, Furey W F, Sax M, Wang B C
Department of Crystallography, University of Pittsburgh, PA 15260.
Proc Natl Acad Sci U S A. 1991 May 15;88(10):4240-4. doi: 10.1073/pnas.88.10.4240.
The crystal structure of a dipeptide complex of bovine neurophysin II has been solved at 2.8 A resolution solely by using single-wavelength anomalous scattering data from a single iodinated derivative. The asymmetric unit is an elongated tetramer of dimensions 110 x 40 x 30 A, composed of two dimers related by pseudo twofold symmetry. Each monomer consists of two homologous layers, each with four antiparallel beta-strands. The two regions are connected by a helix followed by a long loop. Monomer-monomer contacts involve antiparallel beta-sheet interactions, which form a dimer with two layers of eight beta-strands. One peptide per monomer occupies the principal hormone-binding pocket formed by part of the amino-terminal region and parts of the connecting helix and loop, with binding to protein consistent with conclusions drawn from solution studies. Dimer-dimer contacts involve the Tyr49 region adjacent to this site. A fifth dipeptide, of unknown biological significance, helps to stabilize one of the monomer-monomer interfaces and the tetramer-tetramer network in the crystal.
仅通过使用来自单一碘化衍生物的单波长反常散射数据，已在2.8埃分辨率下解析出牛神经垂体素II二肽复合物的晶体结构。不对称单元是一个尺寸为110×40×30埃的细长四聚体，由通过假二重对称相关的两个二聚体组成。每个单体由两个同源层组成，每层有四条反平行β链。这两个区域由一个螺旋和一个长环连接。单体与单体的接触涉及反平行β折叠相互作用，形成一个由两层八条β链组成的二聚体。每个单体中的一个肽占据由氨基末端区域的一部分以及连接螺旋和环的部分形成的主要激素结合口袋，其与蛋白质的结合与溶液研究得出的结论一致。二聚体与二聚体的接触涉及该位点附近的Tyr49区域。一种生物学意义未知的第五种二肽有助于稳定晶体中单体与单体界面之一以及四聚体与四聚体网络。
