PMID:27422842

Citation	Takeuchi, I, Osada, K, Azam, AH, Asakawa, H, Miyanaga, K and Tanji, Y (2016) The Presence of Two Receptor-Binding Proteins Contributes to the Wide Host Range of Staphylococcal Twort-Like Phages. Appl. Environ. Microbiol. 82:5763-74
Abstract	Thanks to their wide host range and virulence, staphylococcal bacteriophages (phages) belonging to the genus Twortlikevirus (staphylococcal Twort-like phages) are regarded as ideal candidates for clinical application for Staphylococcus aureus infections due to the emergence of antibiotic-resistant bacteria of this species. To increase the usability of these phages, it is necessary to understand the mechanism underlying host recognition, especially the receptor-binding proteins (RBPs) that determine host range. In this study, we found that the staphylococcal Twort-like phage ΦSA012 possesses at least two RBPs. Genomic analysis of five mutant phages of ΦSA012 revealed point mutations in orf103, in a region unique to staphylococcal Twort-like phages. Phages harboring mutated ORF103 could not infect S. aureus strains in which wall teichoic acids (WTAs) are glycosylated with α-N-acetylglucosamine (α-GlcNAc). A polyclonal antibody against ORF103 also inhibited infection by ΦSA012 in the presence of α-GlcNAc, suggesting that ORF103 binds to α-GlcNAc. In contrast, a polyclonal antibody against ORF105, a short tail fiber component previously shown to be an RBP, inhibited phage infection irrespective of the presence of α-GlcNAc. Immunoelectron microscopy indicated that ORF103 is a tail fiber component localized at the bottom of the baseplate. From these results, we conclude that ORF103 binds α-GlcNAc in WTAs, whereas ORF105, the primary RBP, is likely to bind the WTA backbone. These findings provide insight into the infection mechanism of staphylococcal Twort-like phages.
Links	PubMed PMC5038044 Online version:10.1128/AEM.01385-16
Keywords
edit table

Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
9CAUD:W0TUZ2		GO:0098670: entry receptor-mediated virion attachment to host cell	ECO:0000315:		P		Figure 6. Takeuchi et al. found that 2 mutations, M103 and M20, in orf103 of phage ΦSA012 enhanced adsorption allowing infection of the normal ΦSA012-resistant organisms that they would otherwise not be able to infect. This was confirmed by adsorption assay and spot testing.	complete CACAO 12435
9CAUD:W0TUZ2		GO:0098024: virus tail, fiber	ECO:0000314:		C		Figure 5. Takeuchi et al. used gold-conjugated anti-orf103 antibodies known to specifically bind to the orf103 gene product. Gold-bound Ab allowed for visualization of the location via immunoelectron microscopy. They found that the gene product localized in the tail fiber at the bottom of the baseplate.	complete CACAO 12440
9CAUD:W0TUZ2		GO:0098001: receptor-mediated bacteriophage reversible attachment to host cell	ECO:0000315:		P		Figures 2 and 3. Takeuchi et al. found that ΦSA012TM103 and ΦSA012TM20 mutant variants of ΦSA012 could not infect host RN4220. ΦSA012TM103 only produced turbid plaques when plated with RN4220 and ΦSA012TM20 could not produce plaques at all. The reason being that RN4220 has the tarM gene which produces α-GlcNAc modification of WTAs. With this modification ΦSA012 mutants cannot infect RN4220. RN4220 with tarM deleted became susceptible to both ΦSA012 mutants as shown in spot tests and adsorption assays.	complete CACAO 12444

References

See Help:References for how to manage references in GONUTS.