Journal: Scientific reports
Article Title: Functional and structural dissection of the tape measure protein of lactococcal phage TP901-1.
PMID/MRN: 27824135
Publication Date: 2016-Nov-08
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 (TMP TP901-1 ) was undertaken. We generated 56 mutants aimed at defining TMP TP901-1 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 TMP TP901-1 as a minimum. Furthermore, the role of TMP TP901-1 in tail length determination was visualized by electron microscopic imaging of TMP-deletion mutants. The inverse linear correlation between the extent of TMP TP901-1 -encoding gene deletions and tail length of the corresponding virion provides an estimate of TMP TP901-1 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.