Omichinski J G, Clore G M, Schaad O, Felsenfeld G, Trainor C, Appella E, Stahl S J, Gronenborn A M
Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892.
Science. 1993 Jul 23;261(5120):438-46. doi: 10.1126/science.8332909.
The three-dimensional solution structure of a complex between the DNA binding domain of the chicken erythroid transcription factor GATA-1 and its cognate DNA site has been determined with multidimensional heteronuclear magnetic resonance spectroscopy. The DNA binding domain consists of a core which contains a zinc coordinated by four cysteines and a carboxyl-terminal tail. The core is composed of two irregular antiparallel beta sheets and an alpha helix, followed by a long loop that leads into the carboxyl-terminal tail. The amino-terminal part of the core, including the helix, is similar in structure, although not in sequence, to the amino-terminal zinc module of the glucocorticoid receptor DNA binding domain. In the other regions, the structures of these two DNA binding domains are entirely different. The DNA target site in contact with the protein spans eight base pairs. The helix and the loop connecting the two antiparallel beta sheets interact with the major groove of the DNA. The carboxyl-terminal tail, which is an essential determinant of specific binding, wraps around into the minor groove. The complex resembles a hand holding a rope with the palm and fingers representing the protein core and the thumb, the carboxyl-terminal tail. The specific interactions between GATA-1 and DNA in the major groove are mainly hydrophobic in nature, which accounts for the preponderance of thymines in the target site. A large number of interactions are observed with the phosphate backbone.
利用多维异核磁共振光谱法已确定了鸡红细胞转录因子GATA-1的DNA结合结构域与其同源DNA位点之间复合物的三维溶液结构。DNA结合结构域由一个核心和一个羧基末端尾巴组成，核心包含一个由四个半胱氨酸配位的锌。核心由两个不规则的反平行β折叠片和一个α螺旋组成，其后是一个通向羧基末端尾巴的长环。核心的氨基末端部分，包括螺旋，在结构上相似，尽管序列不同，与糖皮质激素受体DNA结合结构域的氨基末端锌模块相似。在其他区域，这两个DNA结合结构域的结构完全不同。与蛋白质接触的DNA靶位点跨越八个碱基对。连接两个反平行β折叠片的螺旋和环与DNA的大沟相互作用。作为特异性结合的关键决定因素的羧基末端尾巴缠绕进入小沟。该复合物类似于一只手握住一根绳子，手掌和手指代表蛋白质核心，拇指代表羧基末端尾巴。GATA-1与DNA在大沟中的特异性相互作用主要是疏水性质的，这解释了靶位点中胸腺嘧啶的优势。观察到与磷酸主链有大量相互作用。
