Functional and structural dissection of the tape measure protein of lactococcal phage TP901-1

Jennifer Mahony (1) , Mona Alqarni (1) , Stephen Stockdale (1) , Silvia Spinelli (2) , Marine Feyereisen (1) , Christian Cambillau (2) , Douwe Van Sinderen (1)

1 UCC - University College Cork
2 AFMB - Architecture et fonction des macromolécules biologiques

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.

Mots clés: Bacteriophages; Mutagenesis

Domaines: Biologie structurale [q-bio.BM]; Bio-Informatique, Biologie Systémique [q-bio.QM]

Jennifer Mahony, Mona Alqarni, Stephen Stockdale, Silvia Spinelli, Marine Feyereisen, et al.. Functional and structural dissection of the tape measure protein of lactococcal phage TP901-1. Scientific Reports, 2016, 6 (36667), ⟨10.1038/srep36667⟩. ⟨hal-01439104⟩