Structural Aspects of the Interaction of Dairy Phages with Their Host Bacteria

Jennifer Mahony,Douwe Van Sinderen

doi:10.3390/v4091410

Abstract

Knowledge of phage-host interactions at a fundamental level is central to the design of rational strategies for the development of phage-resistant strains that may be applied in industrial settings. Phages infecting lactic acid bacteria, in particular Lactococcus lactis and Streptococcus thermophilus, negatively impact on dairy fermentation processes with serious economic implications. In recent years a wealth of information on structural protein assembly and topology has become available relating to phages infecting Escherichia coli, Bacillus subtilis and Lactococcus lactis, which act as models for structural analyses of dairy phages. In this review, we explore the role of model tailed phages, such as T4 and SPP1, in advancing our knowledge regarding interactions between dairy phages and their hosts. Furthermore, the potential of currently investigated dairy phages to in turn serve as model systems for this particular group of phages is discussed.

Highlights

Phages are the most abundant biological entities on Earth [1] and are responsible, at least in part, for driving the evolution of their bacterial hosts [2]
Since the most frequently isolated, and the most problematic phages of dairy lactic acid bacteria (LAB) are those belonging to the Siphoviridae and, to a lesser extent, Myoviridae families, we will focus on the former for purposes of clarity
Structural studies relating to T4 in the 1990’s and early 2000’s paved the way for the structural analyses of many phage receptor binding proteins and their associated complexes and have permitted the detailed analysis of several phage-host interactions [9,10,11,12]

Summary

Introduction

Phages are the most abundant biological entities on Earth [1] and are responsible, at least in part, for driving the evolution of their bacterial hosts [2]. Many isolated phages have been characterised morphologically by electron microscopy analysis [3] and the information derived from such analyses may be useful to gain an insight into the position and nature of host receptor (see below). We will explore the role of electron microscopy and structural analysis in defining the interactions between phages and their hosts, and examine the various types of receptor-binding proteins encoded by phages and their corresponding host-encoded receptor. Since the most frequently isolated, and the most problematic phages of dairy lactic acid bacteria (LAB) are those belonging to the Siphoviridae (isolated for Lactococcus, Streptococcus and Lactobacillus spp., among others) and, to a lesser extent, Myoviridae families (isolated for Lactobacillus spp.), we will focus on the former for purposes of clarity

Phages that Recognize a Proteinaceous Receptor

SPP1 as a Model for Protein-Interacting Siphophages of Gram-Positive Bacteria

Lactococcal P335 and 936 Phage-Host Interactions

P335 Phage Baseplates

Conclusions and Future Perspectives