Open AccessRevisiting the host adhesion determinants of Streptococcus thermophilus siphophages
Author(s) -
Lavelle Katherine,
Goulet Adeline,
McDonnell Brian,
Spinelli Silvia,
Sinderen Douwe,
Mahony Jennifer,
Cambillau Christian
Publication year - 2020
Publication title -
microbial biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.287
H-Index - 74
ISSN - 1751-7915
DOI - 10.1111/1751-7915.13593
Subject(s) - streptococcus thermophilus , biology , open reading frame , bacteriophage , mcherry , structural biology , computational biology , green fluorescent protein , microbiology and biotechnology , genetics , peptide sequence , gene , bacteria , escherichia coli , lactobacillus
Summary Available 3D structures of bacteriophage modules combined with predictive bioinformatic algorithms enabled the identification of adhesion modules in 57 siphophages infecting Streptococcus thermophilus (St). We identified several carbohydrate‐binding modules (CBMs) in so‐called evolved distal tail (Dit) and tail‐associated lysozyme (Tal) proteins of St phage baseplates. We examined the open reading frame (ORF) downstream of the Tal‐encoding ORF and uncovered the presence of a putative p2‐like receptor‐binding protein (RBP). A 21 Å resolution electron microscopy structure of the baseplate of cos ‐phage STP1 revealed the presence of six elongated electron densities, surrounding the core of the baseplate, that harbour the p2‐like RBPs at their tip. To verify the functionality of these modules, we expressed GFP‐ or mCherry‐coupled Tal and putative RBP CBMs and observed by fluorescence microscopy that both modules bind to their corresponding St host, the putative RBP CBM with higher affinity than the Tal‐associated one. The large number of CBM functional domains in St phages suggests that they play a contributory role in the infection process, a feature that we previously described in lactococcal phages and beyond, possibly representing a universal feature of the siphophage host‐recognition apparatus.