X‐ray structure of a superinfection exclusion lipoprotein from phage TP‐J34 and identification of the tape measure protein as its target

• Published in: Molecular microbiology 2013-07, Vol.89 (1), p.152-165
• Main Authors: Bebeacua, Cecilia, Lorenzo Fajardo, Juan Carlos, Blangy, Stéphanie, Spinelli, Silvia, Bollmann, Stefanie, Neve, Horst, Cambillau, Christian, Heller, Knut J.
• Format: Article
• Language: English
• Subjects: Biochemistry, Molecular Biology; Cells; Crystallography, X-Ray; Gram-positive bacteria; Life Sciences; Lipoproteins; Lipoproteins - chemistry; Lipoproteins - metabolism; Lysogeny; Microbiology and Parasitology; Molecular biology; Molecular Networks; Molecular structure; Mutation; Prophages - chemistry; Protein Conformation; Proteins; Streptococcus Phages - chemistry; Streptococcus thermophilus; Streptococcus thermophilus - virology; Structural Biology; Viral Proteins - chemistry; Viral Proteins - metabolism; Virology
• ISSN: 0950-382X; 1365-2958
• DOI: 10.1111/mmi.12267

Summary Lipoproteins of temperate phage are a broad family of membrane proteins encoded in the lysogeny module of temperate phages. Expression of the ltpTP‐J34 gene of temperate Streptococcus thermophilus phage TP‐J34 interferes with phage infection at the stage of triggering DNA release and injection into the cell. Here, we report the first structure of a superinfection exclusion protein. We have expressed and determined the X‐ray structure of LtpTP‐J34. The soluble domain of LtpTP‐J34 is composed of a tandem of three‐helix helix–turn–helix (HTH) domains exhibiting a highly negatively charged surface. By isolating mutants of lactococcal phage P008wt with reduced sensitivities to LtpTP‐J34 and by genome sequencing of such mutants we obtained evidence supporting the notion that LtpTP‐J34 targets the phage's tape measure protein (TMP) and blocks its insertion into the cytoplasmic membrane.