Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205, USA.
Biochemistry. 2009 Mar 24;48(11):2321-9. doi: 10.1021/bi801919s.
Helicases are proteins that unwind double-stranded nucleic acids. Dda helicase from bacteriophage T4 has served as an excellent model for understanding the molecular mechanism of this class of enzymes. Study of the structure of Dda may reveal why some helicases translocate in a 5' to 3' direction on DNA, while others translocate in a 3' to 5' direction. Attaining a structure of Dda has proven difficult because the protein fails to readily form crystals and is too large for current NMR technologies. We have developed a homology model of the enzyme which will serve to guide studies that examine the structural and functional significance of the interaction between Dda and DNA and how this interaction affects translocation and unwinding of DNA. We have tested the structural model by using methods for mapping protein domains and for examining protein surfaces that interact with DNA.
解旋酶是能够解开双链核酸的蛋白质。T4 噬菌体的 Dda 解旋酶可用作理解该酶类分子机制的理想模型。Dda 结构的研究可能揭示为何有些解旋酶在 DNA 上沿 5'至 3'方向移动，而有些则沿 3'至 5'方向移动。由于该蛋白不易结晶且过大而无法应用于当前的 NMR 技术，因此获得 Dda 的结构一直很困难。我们已开发出该酶的同源模型，将用于指导研究 Dda 与 DNA 之间相互作用的结构和功能意义，以及这种相互作用如何影响 DNA 的移动和解旋。我们已通过用于绘制蛋白结构域和检测与 DNA 相互作用的蛋白表面的方法对结构模型进行了测试。
