Helicases and remodeling enzymes are ATP-dependent motor proteins that play a critical role in every aspect of RNA and DNA metabolism. Most RNA-remodeling enzymes are members of helicase superfamily 2 (SF2), which includes many DNA helicase enzymes that display similar structural and mechanistic features. Although SF2 enzymes are typically called helicases, many of them display other types of functions, including single-strand translocation, strand annealing, and protein displacement. There are two mechanisms by which RNA helicase enzymes unwind RNA: The nonprocessive DEAD group catalyzes local unwinding of short duplexes adjacent to their binding sites. Members of the processive DExH group often translocate along single-stranded RNA and displace paired strands (or proteins) in their path. In the latter case, unwinding is likely to occur by an active mechanism that involves Brownian motor function and stepwise translocation along RNA. Through structural and single-molecule investigations, researchers are developing coherent models to explain the functions and dynamic motions of helicase enzymes.

中文翻译：

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RNA和DNA解旋酶的易位和解旋机制。

解旋酶和重塑酶是依赖ATP的运动蛋白，在RNA和DNA代谢的各个方面都起着至关重要的作用。大多数RNA重塑酶都是解旋酶超家族2（SF2）的成员，该家族包括许多显示相似结构和机制特征的DNA解旋酶。尽管SF2酶通常被称为解旋酶，但它们中许多都显示其他类型的功能，包括单链易位，链退火和蛋白质置换。RNA解旋酶解开RNA的机制有两种：非加工DEAD基团催化与其结合位点相邻的短双链体的局部解开。进行性DExH组的成员通常沿单链RNA移位并在其路径中置换成对的链（或蛋白质）。在后一种情况下，通过涉及布朗运动功能和沿着RNA的逐步易位的活性机制可能发生解旋。通过结构和单分子研究，研究人员正在开发连贯的模型来解释解旋酶的功能和动态运动。