分辨率为2.8埃的 engrailed 同源结构域-DNA 复合物的晶体结构：理解同源结构域-DNA 相互作用的框架

Crystal structure of an engrailed homeodomain-DNA complex at 2.8 A resolution: a framework for understanding homeodomain-DNA interactions.

作者信息

Kissinger C R, Liu B S, Martin-Blanco E, Kornberg T B, Pabo C O

机构信息

Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205.

出版信息

Cell. 1990 Nov 2;63(3):579-90. doi: 10.1016/0092-8674(90)90453-l.

DOI:10.1016/0092-8674(90)90453-l

PMID:1977522

Abstract

The crystal structure of a complex containing the engrailed homeodomain and a duplex DNA site has been determined at 2.8 A resolution and refined to a crystallographic R factor of 24.4%. In this complex, two separate regions of the 61 amino acid polypeptide contact a TAAT subsite. An N-terminal arm fits into the minor groove, and the side chains of Arg-3 and Arg-5 make contacts near the 5' end of this "core consensus" binding site. An alpha helix fits into the major groove, and the side chains of IIe-47 and Asn-51 contact base pairs near the 3' end of the TAAT site. This "recognition helix" is part of a structurally conserved helix-turn-helix unit, but these helices are longer than the corresponding helices in the lambda repressor, and the relationship between the helix-turn-helix unit and the DNA is significantly different.

摘要

已确定一个包含成对结构域同源异型结构域和双链DNA位点的复合物的晶体结构，分辨率为2.8埃，并将其精修至晶体学R因子为24.4%。在该复合物中，61个氨基酸多肽的两个不同区域与TAAT亚位点接触。一个N端臂嵌入小沟，精氨酸-3和精氨酸-5的侧链在这个“核心共有序列”结合位点的5'端附近形成接触。一个α螺旋嵌入大沟，异亮氨酸-47和天冬酰胺-51的侧链在TAAT位点的3'端附近与碱基对接触。这个“识别螺旋”是结构保守的螺旋-转角-螺旋单元的一部分，但这些螺旋比λ阻遏物中的相应螺旋更长，并且螺旋-转角-螺旋单元与DNA之间的关系显著不同。