PMID:29298884

Citation	'Hernandez-Morales, AC, Lessor, LL, Wood, TL, Migl, D, Mijalis, EM, Russell, WK, Young, RF and Gill, JJ (2018) Genomic and Biochemical Characterization of Podophage Petty Reveals a Novel Lysis Mechanism and Tail-Associated Depolymerase Activity. J. Virol. '
Abstract	The increased prevalence of drug-resistant, nosocomial infections, particularly from pathogenic members of the complex, necessitates the exploration of novel treatments such as phage therapy. In the present study, we characterize phage Petty, a novel podophage that infects multidrug-resistant and Genome analysis reveals that phage Petty is a 40,431bp ϕKMV-like phage, with a coding density of 92.2% and a G+C content of 42.3%. Interestingly, the lysis cassette encodes a class I holin and a single subunit endolysin, but lacks canonical spanins to disrupt the outer membrane. Analysis of other ϕKMV-like genomes revealed that spanin-less lysis cassettes are a feature of phages infecting within this subfamily of bacteriophages. The observed halo surrounding Petty's large clear plaques indicated the presence of a phage-encoded depolymerase capable of degrading capsular exopolysaccharides (EPS). Gene , a putative tail fiber, was hypothesized to possess depolymerase activity based on weak homology to previously reported phage tail fibers. The 101.4 kDa protein gp was cloned and expressed, and its activity against EPS in solution was determined. The enzyme degraded purified EPS from its host strain AU0783, reducing its viscosity, and generated reducing ends in solution, indicative of hydrolase activity. Given that the accessibility to cells within a biofilm is enhanced by degradation of EPS, phages with depolymerases may have enhanced diagnostic and therapeutic potential against drug-resistant strains. Bacteriophage therapy is being revisited as a treatment for difficult-to-treat infections. This is especially true for infections, which are notorious for being resistant to antimicrobials. Thus, sufficient data needs to be generated with regard to phages with therapeutic potential, if they are to be successfully employed clinically. In this study, we describe the isolation and characterization of phage Petty, a novel lytic podophage, and its depolymerase. To our knowledge, it is the first phage reported able to infect both and The lytic phage has potential as an alternative therapeutic agent, and the depolymerase could be used for modulating EPS both during infections and in biofilms on medical equipment, as well as for capsular typing. We also highlight the lack of predicted canonical spanins in the phage genome, and confirm that, unlike the rounding of λ lysogens lacking functional spanin genes, cells infected with phage Petty lyse by bursting. This suggests phages like Petty employ a different mechanism to disrupt the outer membrane of hosts during lysis.
Links	PubMed PMC5827379 Online version:10.1128/JVI.01064-17
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
9CAUD:U5PVS0		GO:0019012: virion	ECO:0000314:		C		Figure 5 used Mass Spectroscopy to show that the gp27/Hypothetical protein/uncharacterized protein was present in the Acinetobacter phage Petty, after first being noticed in the genome by homology in other T7-like phages.	complete CACAO 13374
9CAUD:U5PW88		GO:0019012: virion	ECO:0000314:		C		Figure 5 used Mass Spectroscopy to show that the gp29/Hypothetical protein/uncharacterized protein was present in the Acinetobacter phage Petty, after first being noticed in the genome by homology in other T7-like phages.	complete CACAO 13375
9CAUD:U5PZF1		GO:0019012: virion	ECO:0000314:		C		Figure 5 used Mass Spectroscopy to show that the gp10/Hypothetical protein/uncharacterized protein was present in the Acinetobacter phage Petty, after first being noticed in the genome by homology in other T7-like phages.	complete CACAO 13373
9CAUD:U5PZG8		GO:0019012: virion	ECO:0000314:		C		Figure 5 used Mass Spectroscopy to show that the gp30/Head to tail joining protein was present in the Acinetobacter phage Petty, after first being noticed in the genome by homology in other T7-like phages.	complete CACAO 13372
9CAUD:U5PW98		GO:0016787: hydrolase activity	ECO:0000314:		F		Figure 9 used colorimetric copper-bicinchoninate assay to show that gp39/Dpo1/Tail Fiber Protein from Acinetobacter phage Petty possess hydrolase enzyme activity by producing reducing ends from EPS.	complete CACAO 13309
9CAUD:U5PW98		GO:0051260: protein homooligomerization	ECO:0000314:		P		Figure 8 uses mass exclusion chromatography to suggest gp39/Dpo1/tail fiber protein in Acinetobacter phage petty forms a protein hexamer of identical monomers.	complete
9CAUD:U5PW98		GO:1900232: negative regulation of single-species biofilm formation on inanimate substrate	ECO:0000314:		P		Figure 10 indicates that Dpo1 enzyme from acinetobacter phage Petty negatively regulates biofilm formation of acinetobacter calcoaeticus-baumannii strains. Uniprot name: Tail fiber protein	complete
9CAUD:U5PVL2		GO:0019012: virion	ECO:0000314:		C		Figure 5 suggests that Internal core protein/gp 38 is a cellular component of Acinetobacter phage Petty because mass spectrometry shows it is present in the phage.	complete CACAO 13310
9CAUD:U5PVS9		GO:0019012: virion	ECO:0000314:		C		Fig. 5 suggest that gp37 is a structural protein found in Acinetobacter phage Petty. Protein was identified as part of phage via mass spectroscopy.	complete CACAO 13311
9CAUD:U5PZH2		GO:0019012: virion	ECO:0000314:		C		Figure 5 used Mass Spectroscopy to show that the gp35/Tail Tubular protein B was present in the Acinetobacter phage Petty, after first being noticed in the genome by homology in other T7-like phages.	complete CACAO 13320
9CAUD:U5PVS5		GO:0019012: virion	ECO:0000314:		C		Figure 5 used Mass Spectroscopy to show that the gp32/Capsid Protein was present in the Acinetobacter phage Petty, after first being noticed in the genome by homology in other T7-like phages. Also referenced as the major capsid protein.	complete CACAO 13322
9CAUD:U5PZN7		GO:0019012: virion	ECO:0000314:		C		Fig. 5 suggest that gp36 is an internal virion protein found in Acinetobacter phage Petty. Protein was identified as part of phage via mass spectroscopy.	complete CACAO 13388
9CAUD:U5PW93		GO:0019012: virion	ECO:0000314:		C		Fig. 5 suggest that gp34 is anTail tubular protein A found in Acinetobacter phage Petty. Protein was identified as part of phage via mass spectroscopy.	complete CACAO 13389

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