König P, Richmond T J
Institut für Molekularbiologie und Biophysik ETH-Höngerberg, Zürich, Switzerland.
J Mol Biol. 1993 Sep 5;233(1):139-54. doi: 10.1006/jmbi.1993.1490.
The X-ray structure of the DNA binding domain of the yeast transcriptional activator protein GCN4 bound to a DNA fragment containing the sequence of the perfectly symmetrical ATF/CREB site has been solved to 3.0 A resolution. The architecture of this specific recognition complex supports the current model for bZIP proteins: a homodimer of parallel alpha-helices form an interhelix coiled-coil region via the leucine zipper, and the two N-terminal basic regions fit into the major groove of half sites on opposite sides of the DNA double helix. The structure shows that DNA flexibility plays the predominant role in the preservation of protein contacts with the symmetric ATF/CREB site (ATGACGTCAT) as compared to the pseudo-symmetric AP-1 target site (ATGACTCAT), overcoming the positional displacement of functional groups introduced by the additional G.C base-pair at the center of the ATF/CREB sequence.
已解析出与包含完全对称的ATF/CREB位点序列的DNA片段结合的酵母转录激活蛋白GCN4的DNA结合结构域的X射线结构，分辨率达到3.0埃。这种特异性识别复合物的结构支持了当前关于bZIP蛋白的模型：由平行α螺旋组成的同二聚体通过亮氨酸拉链形成螺旋间卷曲螺旋区域，两个N端碱性区域嵌入DNA双螺旋相对两侧半位点的大沟中。该结构表明，与假对称的AP-1靶位点（ATGACTCAT）相比，DNA灵活性在维持蛋白质与对称ATF/CREB位点（ATGACGTCAT）的接触中起主要作用，克服了ATF/CREB序列中心额外的G.C碱基对引入的官能团位置位移。
