Cai M, Huang Y, Zheng R, Wei S Q, Ghirlando R, Lee M S, Craigie R, Gronenborn A M, Clore G M
Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520, USA.
Nat Struct Biol. 1998 Oct;5(10):903-9. doi: 10.1038/2345.
The solution structure of the human barrier-to-autointegration factor, BAF, a 21,000 Mr dimer, has been solved by NMR, including extensive use of dipolar couplings which provide a priori long range structural information. BAF is a highly evolutionarily conserved DNA binding protein that is responsible for inhibiting autointegration of retroviral DNA, thereby promoting integration of retroviral DNA into the host chromosome. BAF is largely helical, and each subunit is composed of five helices. The dimer is elongated in shape and the dimer interface comprises principally hydrophobic contacts supplemented by a single salt bridge. Despite the absence of any sequence similarity to any other known protein family, the topology of helices 3-5 is similar to that of a number of DNA binding proteins, with helices 4 and 5 constituting a helix-turn-helix motif. A model for the interaction of BAF with DNA that is consistent with structural and mutagenesis data is proposed.
人类屏障自整合因子（BAF）是一种分子量为21,000的二聚体，其溶液结构已通过核磁共振（NMR）解析，其中广泛使用了偶极耦合，该方法可提供先验的长程结构信息。BAF是一种高度进化保守的DNA结合蛋白，负责抑制逆转录病毒DNA的自整合，从而促进逆转录病毒DNA整合到宿主染色体中。BAF主要由螺旋结构组成，每个亚基由五个螺旋组成。二聚体呈细长形，二聚体界面主要由疏水接触组成，并辅以一个盐桥。尽管与任何其他已知蛋白家族没有任何序列相似性，但螺旋3至5的拓扑结构与许多DNA结合蛋白相似，其中螺旋4和5构成一个螺旋-转角-螺旋基序。本文提出了一个与结构和诱变数据一致的BAF与DNA相互作用模型。
