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Researchers analyzed over 7,000 genomes of huge phages (viruses that infect bacteria with genomes larger than 200 kilobases) and discovered they encode numerous proteins involved in bacterial cell envelope functions. The study identified previously unknown phage-encoded proteins including sortase B, phage shock protein A, and over 1,600 beta-barrel outer membrane proteins, particularly abundant in human gut-associated phages. These proteins showed structural diversity and habitat-specific patterns, with metatranscriptomic data confirming their expression in natural microbial communities.
Why it matters
This discovery reveals a previously unrecognized mechanism by which large phages may manipulate bacterial host cell surfaces and membranes, potentially influencing microbial community dynamics in important ecosystems like the human gut. Understanding these phage-host interactions could inform development of phage-based therapeutics and provide insights into bacterial physiology in complex microbiomes.
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⚠️ Preprint – Noch nicht peer-reviewed
Dieser Artikel wurde noch nicht von unabhängigen Experten begutachtet. Die Ergebnisse sind vorläufig und sollten mit Vorsicht interpretiert werden.
Huge phages (or jumbo phages, >200 kilobases) encode extensive protein repertoires, yet their functional diversity and potential roles in host physiology remain poorly understood. Using protein structure-based analyses of dominant protein families across 7,187 non-redundant genomes of huge phages, we uncovered pronounced phylogenetic and habitat-associated diversification. Notably, we identified diverse proteins associated with bacterial cell envelope functions, particularly in human gut-associated huge phages. These included previously unreported phage-encoded sortase B, whose putative substrates contain signal peptides and cell-wall sorting signals, suggesting a potential route for displaying phage proteins on bacterial surfaces. Phage-encoded phage shock protein A (PspA) was distributed across diverse lineages and frequently neighbored genes associated with membrane organization and transport, implicating potential roles in membrane physiology. We also identified 1,603 {beta}-barrel outer membrane proteins (OMPs) across 1,303 huge phages from diverse ecosystems. These OMPs exhibited structural diversity and associations with predicted host taxonomy, habitat, and neighboring envelope-related genes. Metatranscriptomic analysis supported expression of representative phage-encoded PspA and OMP genes in natural communities including the human gut. Together, these findings reveal bacterial cell envelope processes as a previously underappreciated potential interface for huge phage-host interactions.
Source: Large-genome phages encode diverse proteins associated with host cell envelope functions