Guo P, Peterson C, Anderson D
Department of Microbiology, University of Minnesota, Minneapolis 55455.
J Mol Biol. 1987 Sep 20;197(2):229-36. doi: 10.1016/0022-2836(87)90121-5.
The ATPase activity of the DNA packaging protein gp16 (gene product 16) of bacteriophage phi 29 was studied in the completely defined in-vitro assembly system. ATP was hydrolyzed to ADP and Pi in the packaging reaction that included purified proheads, DNA-gp3 and gp16. Approximately one molecule of ATP was used in the packaging of 2 base-pairs of phi 29 DNA, or 9 X 10(3) ATP molecules per virion. The hydrolysis of ATP by gp16 was both prohead and DNA-gp3 dependent. gp16 contained both the "A-type" and the "B-type" ATP-binding consensus sequences (Walker et al., 1982) and the predicted secondary structure for ATP binding. The A-type sequence of gp16 was "basic-hydrophobic region-G-X2-G-X-G-K-S-X7-hydrophobic", and similar sequences were found in the phage DNA packaging proteins gpA of lambda, gp19 of T7 and gp17 of T4. Having both the ATP-binding and potential magnesium-binding domains, all of these proteins probably function as ATPases and may have common prohead-binding capabilities. The phi 29 protein gp3, covalently bound to the DNA, may be analogous in function to proteins gpNul of lambda and gpl of phi 21 that bind the DNA.
在完全确定的体外组装系统中研究了噬菌体φ29的DNA包装蛋白gp16（基因产物16）的ATP酶活性。在包括纯化的原头部、DNA-gp3和gp16的包装反应中，ATP被水解为ADP和Pi。包装2个碱基对的φ29 DNA大约消耗1分子ATP，即每个病毒粒子消耗9×10³个ATP分子。gp16对ATP的水解既依赖于原头部，也依赖于DNA-gp3。gp16包含“A型”和“B型”ATP结合共有序列（Walker等人，1982）以及预测的ATP结合二级结构。gp16的A型序列为“碱性-疏水区域-G-X2-G-X-G-K-S-X7-疏水”，在噬菌体DNA包装蛋白λ的gpA、T7的gp19和T4的gp17中也发现了类似序列。由于具有ATP结合和潜在的镁结合结构域，所有这些蛋白质可能都作为ATP酶发挥作用，并且可能具有共同的原头部结合能力。与DNA共价结合的φ29蛋白gp3在功能上可能类似于λ的gpNul蛋白和φ21的gpl蛋白，它们都能结合DNA。
