Volozhantsev, N. | bioRxiv Science

bioRxiv2026

Phages infecting the common gut commensal Escherichia coli HS reveal tropism for its Klebsiella-like capsule

Tailed dsDNA phages are ubiquitous and thought to infect almost any bacterial species. Escherichia coli HS - a commensal strain used as a model in gut colonization studies - has not been reported as a host for dsDNA phages and is resistant to more than 100 coliphages from the BASEL collection. Here, we report the first phages infecting E. coli HS, characterize their interaction with an endogenous BREX system, and provide a detailed genomic and phylogenetic description. Phages {phi}HS1 (Queuovirinae) and {phi}HS2 (Ackermannviridae) possess dPreQ and 5-NeOmdU modifications that confer resistance to restriction digestion. {phi}HS3 is a temperate phage, related to the native HS prophage {phi}HS4, and represents a founding member of a novel genus (Hueyvirus) of P22-like phages capable of lateral transduction. We reveal exchange of tailspike genes between {phi}HS2, {phi}HS3, and Klebsiella-specific phages. Furthermore, we demonstrate that E. coli HS encodes a Klebsiella-like K47 capsule required for phage infection. These results suggest that the broad phage resistance of E. coli HS may be linked to its capsular type.

microbiology↗

bioRxiv2019

Crystal Structure of the putative tail fiber protein gp53 from the Acinetobacter baumannii bacteriophage AP22

This report describes the structure of a putative tail fiber protein of the Acinetobacter baumannii bacteriophage AP22. The target host range of strictly lytic bacteriophage AP22 includes many clinical isolates of A. baumannii from hospitals in Chelyabinsk, Nizhny Novgorod, Moscow and St. Petersburg (Russia), but its host cell binding apparatus remains uncharacterized. Here, we report the crystal structure of the C-terminal fragment of AP22 gene product 53 (gp53) one of its two putative host cell-binding proteins. We show that gp53 forms a trimeric fiber and binds ethylene glycol and glycerol molecules that represent known surrogates of the oligosaccharide backbone. However, despite its structural similarities to other phage/virus host cell-binding fibers and its binding to small sugar-like molecules, gp53 did not inhibit AP22 infection and its role in the infection process remains unclear.

biophysics↗