STRUCTURE OF VIRAL DNA PACKAGING MACHINE & PACKAGING INTERMEDIATES

枯草芽孢杆菌噬菌体1029是一个很好的研究模型 病毒DNA的包装。 029 DNA的体外包装系统， 与体内组装一样有效。 DNA包装的模型可以 测试并确定组分的结构。 小行星1029 在每个末端具有共价结合的基因产物3（DNA-gp 3）， 在体外通过一个微球转移到预先形成的prvteir壳（prohead）中， 包括探头的门顶点和头尾连接器的机器）， 174个碱基的4029编码的前头RNA和ATP酶gp 16。 的 前头部、连接子、pRNA和gp 16都是从克隆的 基因允许这些成分的结构顺序 与DNA-gp 3的相互作用有待研究。 超螺旋pBR 322 DNA包裹物 隔离4~29连接器的外部周围。 这是 这一假设反映了DNA包装的初始阶段。 在这 模型，proheads也应该结合超螺旋DNA和40 DNA-gp 3应该 作为包装的先决条件。 ，RNA假结， 推测pRNA中存在分子内三级相互作用， 然后通过基因突变得到证实。 两个变种人，温奇 能使分子内假结， prohead包装试验表明，他们可能会使一个 分子间假结 测量不同pRNA的质量， STEM来确认这一点 它计划看看 STEM中的pRNA连接器复合物。

Bacteriophage 1029 of A subtilis is an excellent model for studies of viral DNA packaging. The in vitro packaging system of (029 DNA is as efficient as in vivo assembly. Models of DNA packaging can be tested and the structum of components can be determined. 1029 DNA with covalently bound gene product 3 at each terminus (DNA-gp3) is translocated in vitro into a preformed prvteir~shell (prohead) by a machine that includes the prohead'portal vertex Oead-tail comector), the 174-base 4029-encoded prohead RNA.and the ATPase gp16. The prohead, connector, pRNA and gp16 are all overproduced from cloned genes permitting the structure of these components in sequential interactions with DNA-gp3 to be studied. Supercoiled pBR322 DNA wraps around the outside of the isolated 4~29 connector. This is hypothesized to reflect the initial phase of DNA packaging. In this model, proheads should also bind supercoiled DNA and 40 DNA-gp3 should be supercoiled as a prerequisite for packaging. , An RNA pseudoknot, an intramolecular tertiary interaction, in the pRNA was inferred and then confirmed by genetic mutations. Two mutants, neither of winch can make the mtramolecular pseudoknot, can complement each other in the prohead packaging assay indicating they might make an intermolecular psuedoknot. Masses of different pRNAs were measured in the STEM to try to confirm this. It is planned to look at pRNA-connector complexes in the STEM.