Siphoviridae phage tails co-enrich with ex vivo amyloids.

Bacteriophages are ubiquitous in the environment and are part of the natural human microbiome. Despite their abundance, the role of the human phagome in health and disease remains poorly understood. Here, we identify phage tails in ex vivo amyloid extracts from patients with lysozyme amyloidosis (ALys) and light-chain amyloidosis (AL). Using cryo-EM analysis of the ALys dataset, automated model building, and database searches, we assigned the observed tubular assemblies to a phage tail tube protein (TTP). Although we cannot fully rule out the possibility of contamination, the presence of phage tails raises the question of whether they bind to and are co-purified with amyloid fibrils. These structures may provide further insight into the potential relationship between phage-derived assemblies and amyloid remodeling, with possible implications for future therapeutic strategies in human amyloidosis.