A critical role in structure-specific DNA binding for the acetylatable lysine residues in HMGB1
A critical role in structure-specific DNA binding for the acetylatable lysine residues in HMGB1
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DOI：
10.1042/bj20071613
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发表时间：
2008-05-01
影响因子：
4.1
通讯作者：
Thomas, Jean O.
中科院分区：
文献类型：
--
作者：
Assenberg, Ren;WebB, Michelle;Thomas, Jean O.
结构特异性DNA结合蛋白HMGB1（高迁移率族蛋白B1）包含两个串联的HMG盒（A和B）和酸性C末端尾，在体内在A盒中的Lys（2）和Lys（11）处被乙酰化。突变为丙氨酸的两个残基在分离的A域，它具有强烈的偏好预弯曲的DNA，废除结合四路交界处和88 bp的DNA微环。全长HMGB I中的相同突变也消除了其与四向连接的结合，并且与小环的结合基本上受损。相反，当酸性尾不存在时（AB双结构域），双突变对四向连接结合的影响很小，尽管与小环的结合降低了类似于15倍。因此，似乎在AB中，B结构域能够取代非功能性A结构域，而在全长HMGB I中，B结构域被酸性尾掩蔽。在任何情况下，赖氨酸（2）或赖氨酸（11）的单一取代都不会消除DNA结合。双突变不会显著扰乱A结构域的结构。我们的结论是，赖氨酸（2）和赖氨酸（11）是关键的分离的A结构域和HMGB1的扭曲的DNA底物的结合。
The structure-specific DNA-binding protein HMGB1 (high-mobility group protein B1) which comprises two tandem HMG boxes (A and B) and an acidic C-terminal tail, is acetylated in vivo at Lys(2) and Lys(11) in the A box. Mutation to alanine of both residues in the isolated A domain, which has a strong preference for pre-bent DNA, abolishes binding to four-way junctions and 88 bp DNA minicircles. The same mutations in full-length HMGB I also abolish its binding to four-way junctions, and binding to minicircles is substantially impaired. In contrast, when the acidic tail is absent (AB di-domain) there is little effect of the double mutation on four-way junction binding, although binding to minicircles is reduced similar to 15-fold. Therefore it appears that in AB the B domain is able to substitute for the non-functional A domain, whereas in full-length HMGB I the B domain is masked by the acidic tail. In no case does single substitution of Lys(2) or Lys(11) abolish DNA binding. The double mutation does not significantly perturb the structure of the A domain. We conclude that Lys(2) and Lys(11) are critical for binding of the isolated A domain and HMGB1 to distorted DNA substrates.