The precursor complex of Pf3 bacteriophage.
The precursor complex of Pf3 bacteriophage.
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Pf3 噬菌体的前体复合物。
DOI：
10.1016/0042-6822(85)90159-x
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发表时间：
1985
期刊：
影响因子：
3.7
通讯作者：
L. Day
中科院分区：
文献类型：
--
作者：
A. Casadevall;L. Day
丝状噬菌体感染产生由环状单链DNA分子和大约103个拷贝的病毒编码的单链DNA结合蛋白组成的细胞内丝状前体复合物。开发了一种从Pf 3噬菌体感染的铜绿假单胞菌细胞中纯化前体复合物的方案，并通过引入分子筛柱步骤对Ff和Pfl复合物的现有方案进行了修正。Pf 3前体复合物的平均轮廓长度为500 nm，比成熟Pf 3病毒的轮廓长度短。M/L（质量/长度）值由浊度测量、扫描透射电子显微镜和总颗粒质量除以其长度获得。获得的平均M/L为19，300 Da/nm，接近Pf 3病毒粒子的M/L。复合物的核苷酸/亚基比为6.0。前体复合物的蛋白质组分的α-螺旋度小于10%，而病毒的蛋白质组分的α-螺旋度大于90%。前体中的DNA结构与病毒中的DNA结构非常不同，因此在病毒组装期间，DNA结构必须发生显着变化。Pf 3系统的结果，连同Ff和Pfl丝状病毒系统的可用信息，表明不同的DNA-蛋白质相互作用和包装安排参与执行等效功能。
Filamentous bacteriophage infections give rise to intracellular filamentous precursor complexes composed of a circular single-stranded DNA molecule and on the order of 103 copies of a viral-encoded, single-stranded DNA binding protein. A protocol was developed for the purification of the precursor complex from Pf3 phage-infectedPseudomonas aeruginosacells, and existing protocols for Ff and Pfl complexes were amended by the introduction of a molecular sieving column step. The Pf3 precursor complex has an average contour length of 500 nm, which is shorter than that of the mature Pf3 virus.M/L(mass/ length) values were obtained from turbidity measurements, from scanning-transmission electron microscopy, and from the total particle mass divided by its length. The averageM/Lobtained was 19,300 Da/nm which is close to that of the Pf3 virion. The complex has a nucleotide/subunit ratio of 6.0. The protein component of the precursor complex has less than 10% α-helicity, whereas the protein component of the virus is greater than 90% α-helical. The DNA structure in the precursors is very different from that in the virus, so that during virus assembly the DNA structure must change dramatically. The results for the Pf3 system, together with the available information for the Ff and Pfl filamentous virus systems, indicate that different DNA-protein interactions and packing arrangements are involved in performing equivalent functions.