TY - JOUR T1 - Phylogenetic and structural diversity of aromatically dense pili from environmental metagenomes JF - bioRxiv DO - 10.1101/668343 SP - 668343 AU - M. S. Bray AU - J. Wu AU - C.C. Padilla AU - F. J. Stewart AU - D. A. Fowle AU - C. Henny AU - R. L. Simister AU - K. J. Thompson AU - S. A. Crowe AU - J. B. Glass Y1 - 2019/01/01 UR - http://biorxiv.org/content/early/2019/10/15/668343.abstract N2 - 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.Originality and Significance Electroactive pili (e-pili) are used by microorganisms to respire solid metals in their environment through extracellular electron transfer. Thus, e-pili enable microbes to occupy specific environmental niches. Additionally, e-pili have important potential for biotechnological applications. Currently the repertoire of known e-pili is small, and their environmental distribution is largely unknown. Using sequence analysis, we identified numerous genes encoding putative e-pili from diverse anoxic, metal-rich ecosystems. Our results expand the diversity of putative e-pili in environments where metal oxides may be important electron acceptors for microbial respiration. ER -