Phylogenetic and structural diversity of aromatically dense pili from environmental metagenomes

Abstract

Summary Electroactive type IV pili, or e‐pili, are used by some microbial species for extracellular electron transfer. Recent studies suggest that e‐pili may be more phylogenetically and structurally diverse than previously assumed. Here, we used updated aromatic density thresholds (≥9.8% aromatic amino acids, ≤22‐aa aromatic gaps and aromatic amino acids at residues 1, 24, 27, 50 and/or 51, and 32 and/or 57) to search for putative e‐pilin genes in metagenomes from diverse ecosystems with active microbial metal cycling. Environmental putative e‐pilins were diverse in length and phylogeny, and included truncated e‐pilins in Geobacter spp., as well as longer putative e‐pilins in Fe(II)‐oxidizing Betaproteobacteria and Zetaproteobacteria.