TY - JOUR T1 - Electrically Conductive Pili from Pilin Genes of Phylogenetically Diverse Microorganisms JF - bioRxiv DO - 10.1101/118059 SP - 118059 AU - David J.F. Walker AU - Ramesh Y. Adhikari AU - Dawn E. Holmes AU - Joy E. Ward AU - Trevor L. Woodard AU - Kelly P. Nevin AU - Derek R. Lovley Y1 - 2017/01/01 UR - http://biorxiv.org/content/early/2017/03/18/118059.abstract N2 - The possibility that bacteria other than Geobacter species might contain genes for electrically conductive pili (e-pili) was investigated by heterologously expressing pilin genes of interest in Geobacter sulfurreducens. Strains of G. sulfurreducens producing high current densities, which are only possible with e-pili, were obtained with pilin genes from Flexistipes sinusarabici, Calditerrivibrio nitroreducens, and Desulfurivibrio alkaliphilus. The conductance of pili from these strains was comparable to native G. sulfurreducens e-pili. The e-pili derived from C. nitroreducens, and D. alkaliphilus pilin genes are the first examples of relatively long (> 100 amino acids) pilin monomers assembling into e-pili. The pilin gene from Desulfofervidus auxilii did not yield e-pili, suggesting that the hypothesis that this sulfate reducer wires itself to ANME-1 microbes with e-pili to promote anaerobic methane oxidation should be reevaluated. A high density of aromatic amino acids and a lack of substantial aromatic-free gaps along the length of long pilins may be important characteristics leading to e-pili. This study demonstrates a simple method to screen pilin genes from difficult-to-culture microorganisms for their potential to yield e-pili; reveals new potential sources for biologically based electronic materials; and suggests that a wide phylogenetic diversity of microorganisms may employ e-pili for extracellular electron exchange. ER -