Ubiquitous Carbohydrate Binding Modules Decorate 936 Lactococcal Siphophage Virions

Area of Science:

• Microbiology
• Structural Biology
• Bioinformatics

Background:

• Advancements in 3D structural analysis and in silico tools enable detailed study of bacteriophage assembly and function.
• Bacteriophages, particularly siphophages, possess complex adhesion devices crucial for host interaction.

Purpose of the Study:

• To investigate the role of Carbohydrate Binding Modules (CBMs) in the adhesion mechanisms of 936 group lactococcal siphophages.
• To assess the host-binding capabilities of CBM-containing proteins from these phages.

Main Methods:

• Examination of 113 members of the 936 group of lactococcal siphophages.
• Identification of CBMs within phage neck passage structures and major tail proteins.
• Construction of green fluorescent protein fusion proteins for binding assays.
• Bioinformatic analysis of structural proteins for homology.

Main Results:

• Carbohydrate Binding Modules (CBMs) were identified in the neck passage and major tail protein of 936 group phages.
• Two specific CBMs, one from the phage tail and one from the neck, showed confirmed binding to their respective phage-specific hosts.
• Bioinformatic analysis revealed structural homology of these binding modules with those in other lactococcal phage groups, suggesting conserved evolutionary strategies.

Conclusions:

• Carbohydrate Binding Modules (CBMs) are integral components of siphage adhesion devices, playing a significant role in host recognition and infection.
• The presence and structural homology of CBMs across different phage groups indicate a conserved evolutionary approach to enhance host binding.
• The modular nature of CBMs allows for versatile combinations, facilitating adaptation to diverse ecological niches and ensuring successful host detection.