MECHANISM OF DNA-BINDING TO THE GENE-5 PROTEIN OF BACTERIOPHAGE-FD
MECHANISM OF DNA-BINDING TO THE GENE-5 PROTEIN OF BACTERIOPHAGE-FD
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DOI：
10.1021/bi00297a025
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发表时间：
1984-01-01
期刊：
影响因子：
2.9
通讯作者：
MCPHERSON, A
中科院分区：
文献类型：
--
作者：
BRAYER, GD;MCPHERSON, A
基于差分傅里叶分析以及结构和物理化学数据之间的相关性，提出了单链 DNA 与噬菌体 fd 基因 5 DNA 结合蛋白 (G5BP) 相互作用产生的双分子复合物模型。重要的 DNA 结合元件是 G5BP 二聚体，它提供 2 个反向平行 DNA 结合通道，每个通道均由该对内两个单体的氨基酸贡献构成。由于每个二聚体单元内固有的二元对称性，这些通道显示出相同的键合环境，但极性相反。 2 个通道间隔 30 ANG，每个通道间隔 10 ANG。宽，40 ANG。长的。显然，DNA 结合是两组一般相互作用的结果。 G5BP 的芳香侧链堆积在核酸碱基上，DNA 磷酸主链由一系列适当位置的赖氨酰和精氨酰侧链结合。 DNA构象完全延伸，每个结合通道最多可容纳5个核苷酸。只需要对天然 G5BP 结构进行微小的构象变化即可优化 DNA 的结合。 G5BP-DNA 络合模型用于解释与该蛋白质在噬菌体 fd 生命周期中核蛋白螺旋形成中所发挥的作用相关的一些机制特征。
A model for the bimolecular complex arising from the interaction of single-stranded DNA with the gene 5 DNA binding protein (G5BP) of bacteriophage fd is proposed on the basis of difference Fourier analyses, and the correlation between structural and physicochemical data. The essential DNA binding element is the G5BP dimer which provides 2 antiparallel DNA binding channels, each constructed from amino acid contributions of both monomers within the pair. These channels display identical bonding environments but opposite polarities as a consequence of the inherent dyad symmetry within each dimer unit. The 2 channels are separated by 30 .ANG., and each is 10 .ANG. wide and 40 .ANG. long. Evidently, DNA binding is a consequence of 2 general sets of interactions. Aromatic side chains of G5BP stack upon nucleic acid bases, and the DNA phosphate backbone is bound by a series of appropriately positioned lysyl and arginyl side chains. The DNA conformation is fully extended and each binding channel can accommodate up to 5 nucleotides. Only minor conformation changes in the native G5BP structure are required to optimize the binding of DNA. The G5BP-DNA complexation model serves to explain some of the mechanistic features associated with the role this protein plays in the formation of a nucleoprotein helix during the bacteriophage fd life cycle.