SOLUTION STRUCTURE OF A DNA-BINDING UNIT OF MYB - A HELIX TURN HELIX-RELATED MOTIF WITH CONSERVED TRYPTOPHANS FORMING A HYDROPHOBIC CORE
SOLUTION STRUCTURE OF A DNA-BINDING UNIT OF MYB - A HELIX TURN HELIX-RELATED MOTIF WITH CONSERVED TRYPTOPHANS FORMING A HYDROPHOBIC CORE
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DOI：
10.1073/pnas.89.14.6428
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发表时间：
1992-07-15
影响因子：
11.1
通讯作者：
NISHIMURA, Y
中科院分区：
文献类型：
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作者：
OGATA, K;HOJO, H;NISHIMURA, Y
c-myb原癌基因产物的dna结合域由三个51或52个氨基酸的不完全串联重复序列组成，每个重复序列包含三个保守的色氨酸，间隔18或19个氨基酸。第三个重复的结构，这是必不可少的序列特异性DNA结合，已确定与距离几何计算核磁共振。它包括三个定义明确的螺旋（残基149-162、166-172和178-187），由一个疏水核心维持，疏水核心包括三个保守的色氨酸和两个组氨酸。螺旋2和螺旋3形成的结构与典型的螺旋-转-螺旋基序相关，但又不同。特别是，这些螺旋之间的旋转比细菌阻遏物和同源结构域的相应旋转长一个氨基酸，并含有脯氨酸残基。此外，这三个螺旋的结构与细菌阻遏物的同源结构域和dna结合结构域不同。在现有结构的基础上，讨论了Myb重复序列3与特定DNA的结合模式。
The DNA-binding domain of the c-myb protooncogene product consists of three imperfect tandem repeats of 51 or 52 amino acids, each of which contains three conserved tryptophans, spaced 18 or 19 amino acids apart. The structure of the third repeat, which is essential for sequence-specific DNA binding, has been determined by NMR with distance geometry calculation. It includes three well-defined helices (residues 149-162, 166-172, and 178-187) maintained by a hydrophobic core that includes the three conserved tryptophans, together with two histidines. Helices 2 and 3 form a structure related to but distinct from a canonical helix-turn-helix motif. In particular, the turn between these helices is one amino acid longer than the corresponding turn in bacterial repressors and homeodomains and contains a proline residue. In addition, the architecture of the three helices is different from those of homeodomains and DNA-binding domains of bacterial repressors. Based on the present structure, the binding mode of Myb repeat 3 with a specific DNA is also discussed.