PMID:27824135

Citation	Mahony, J, Alqarni, M, Stockdale, S, Spinelli, S, Feyereisen, M, Cambillau, C and Sinderen, DV (2016) Functional and structural dissection of the tape measure protein of lactococcal phage TP901-1. Sci Rep 6:36667
Abstract	The tail tape measure protein (TMP) of tailed bacteriophages (also called phages) dictates the tail length and facilitates DNA transit to the cell cytoplasm during infection. Here, a thorough mutational analysis of the TMP from lactococcal phage TP901-1 (TMPTP901-1) was undertaken. We generated 56 mutants aimed at defining TMPTP901-1 domains that are essential for tail assembly and successful infection. Through analysis of the derived mutants, we determined that TP901-1 infectivity requires the N-terminal 154 aa residues, the C-terminal 60 residues and the first predicted hydrophobic region of TMPTP901-1 as a minimum. Furthermore, the role of TMPTP901-1 in tail length determination was visualized by electron microscopic imaging of TMP-deletion mutants. The inverse linear correlation between the extent of TMPTP901-1-encoding gene deletions and tail length of the corresponding virion provides an estimate of TMPTP901-1 regions interacting with the connector or involved in initiator complex formation. This study represents the most thorough characterisation of a TMP from a Gram-positive host-infecting phage and provides essential advances to understanding its role in virion assembly, morphology and infection.
Links	PubMed PMC5099701 Online version:10.1038/srep36667
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
9CAUD:Q9G097		GO:0098004: virus tail fiber assembly	ECO:0000315: mutant phenotype evidence used in manual assertion		P		56 mutants were created to characterize which domains of TP901-1's tape measure gene (TMP) were essential for infection of the phage and it's tail assembly. Through this experiment, TP901-1's N-terminal 154 amino acid residues, C-terminal 60 residues, and hydrophobic region were revealed to be required for TP901's infectivity. This is shown in fig.2 in the paper, where removing 30 amino acids from both N and C-termini cause phage assembly to be aberrant, while removal of the hydrophobic region causes tai length reduction.	complete CACAO 12553
9CAUD:Q9G097		GO:0098026: virus tail, tube	ECO:0000315:		C		A series of different mutations were made in the TMP of this phage, including in the N-termini, C-termini, and hydrophobic regions of the protein. Figure 2 shows that mutations in the N and C-termini resulted in abnormal phage assembly, and hydrophobic region mutations resulted in tail length reduction. Therefore, the TMP is determined to be an important part of the tube in the viral tail.	complete CACAO 12588
9CAUD:Q9G097	Contributes to	GO:0098003: viral tail assembly	ECO:0000315:		P		The 29 repeats of the tape measure protein are essential to virion structure. Deletion mutants for repeat copies were constructed, then had tail length measured through electron microscopy. Authors found that, with increased deletion of repeat sequences, the phage tail shortened (Table 2). For example, normal phage tail length is 118nm, but repeat 1-29 deletion mutants had a tail of 65 nm.	complete CACAO 13108

References

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