PMID:23011306

Citation	Shen, X, Li, M, Zeng, Y, Hu, X, Tan, Y, Rao, X, Jin, X, Li, S, Zhu, J, Zhang, K and Hu, F (2012) Functional identification of the DNA packaging terminase from Pseudomonas aeruginosa phage PaP3. Arch. Virol. 157:2133-41
Abstract	Terminase proteins are responsible for DNA recognition and initiation of DNA packaging in phages. We previously reported the genomic sequence of a temperate Pseudomonas aeruginosa phage, PaP3, and determined its precise integration site in the host bacterial chromosome. In this study, we present a detailed functional identification of the DNA packaging terminase for phage PaP3. The purified large subunit p03 was demonstrated to possess ATPase and nuclease activities, as well as the ability to bind to specific DNA when it is unassembled. In addition, a small terminase subunit (p01) of a new type was found and shown to bind specifically to cos-containing DNA and stimulate the cos-cleavage and ATPase activities of p03. The results presented here suggest that PaP3 utilizes a typical cos site mechanism for DNA packaging and provide a first step towards understanding the molecular mechanism of the PaP3 DNA packaging reaction.
Links	PubMed PMC3488191 Online version:10.1007/s00705-012-1409-5
Keywords	Adenosine Triphosphatases/genetics; Adenosine Triphosphatases/metabolism; DNA Packaging; DNA, Viral/metabolism; Deoxyribonucleases/genetics; Deoxyribonucleases/metabolism; Endodeoxyribonucleases/genetics; Endodeoxyribonucleases/metabolism; Protein Binding; Pseudomonas Phages/enzymology; Pseudomonas Phages/genetics; Pseudomonas Phages/physiology; Pseudomonas aeruginosa/virology
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
9CAUD:Q8H9R7		GO:0098009: virus terminase, large subunit	ECO:0000314:		C		The Orf3 Gene has a terminase function. Terminase typically has two subunits, the smaller is responsible for binding the viral DNA, while the larger subunit is responsible primarily for DNA cleavage and translocation. This particular gene makes the protein p03, which is the larger subunit in the terminase process (Figure 1). When unassembled from p01, p03 can typically perform the binding function by itself, however, when performing endonucleolytic activity, efficiency was tested, and was found to perform higher when both p01 and p03 were present (Figure 4).	complete CACAO 11781
9CAUD:Q8H9R7		GO:0016887: ATPase activity	ECO:0000314:		F		ATPase Activity has been found to be largely associated with the large subunit in terminase in this phage. This has been found through sequence analysis, as well as experimentally. The ATPase activity from p03 gel filtration columns were analyzed and it was found that there is a direct, positive correlation between the amount of product made and the presence of p03. The ATPase product greatly increases with the addition of p01 (the small subunit of terminase) as well. See Figure 6.	complete CACAO 11958
9CAUD:Q8H9R7		GO:0043493: viral terminase complex	ECO:0000314:		C		The terminase function in this phage requires both of the proteins p01 and p03. The p01 protein in this phage corresponds to the small subunit of terminase, while p03 corresponds to the large subunit of terminase. Although p03 can function without p01, p01 cannot function without p03. However, the endonucleolytic activity of p03 functions more effectively with the presence of p01. Thus exhibiting a cos-dependent endonucleolytic activity. See Figure 3	complete CACAO 11964

References

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