枯草芽孢杆菌全长引物酶的溶液结构研究

在细菌DNA复制中，DnaG引物酶合成RNA引物，然后合成的引物通过DNA聚合酶进行延伸. DnaG引物酶由3个结构域组成，N端锌结合结构域（zinc-binding domain,ZBD）、RNA聚合酶结构域（RNA polymerase domain,RPD）和C端解旋酶结合结构域（helicase binding domain,HBD）. 在合成引物的过程中，引物酶的3个结构域协同作用，缺一不可. 尽管引物酶3个结构域的结构均已有研究报道，但到目前为止，引物酶的全长结构尚不清楚. 我们在上海光源利用小角X射线散射技术研究了枯草芽孢杆菌全长引物酶的溶液结构,首次构建了全长引物酶结构模型. 我们发现，枯草芽孢杆菌引物酶在溶液中处于伸展状态，且ZBD和HBD结构域相对于RPD结构域呈现出连续的构象变化. 本文研究表明DnaG引物酶中的结构域重排可能有助于其在DNA复制中发挥功能.

The Study on The Solution Structure of Full Length Primase From Bacillus subtilis

In bacterial DNA replication, DnaG primase synthesizes RNA primers which are then extended by DNA polymerase. The DnaG primase consists of three domains, N-terminal zinc-binding domain (ZBD), RNA polymerase domain (RPD) and C-terminal helicase binding domain (HBD). In the process of producing primers, the three domains of primase cooperate with each other, and none is dispensable. Although the structures of the primase domains have been reported, so far, the full-length structure of the primase is not known yet. Here, the model of full-length DnaG in Bacillus subtilis (BsuDnaG) was constructed from the data of X-ray small angle scattering (SAXS) analysis. The BsuDnaG is in extended state in solution. On the other hand, the ZBD and HBD domains could exhibit continuous conformational changes relative to the RPD domain. This study suggests the domains rearrangement in DnaG primase may facilitate its function in DNA replication.