Genome Scale Mutational Analysis of Geobacter sulfurreducens Reveals Distinct Molecular Mechanisms for Respiration and Sensing of Poised Electrodes versus Fe(III) Oxides.

摘要: Geobacter sulfurreducens generates electrical current by coupling intracellular oxidation of organic acids to the reduction proteins on cell surface that are able interface with electrodes. This ability is attributed bacterium's capacity respire other extracellular electron acceptors require contact, such as insoluble metal oxides. To directly investigate genetic basis electrode-based respiration, we constructed transposon-insertion sequencing (Tn-Seq) libraries for growth, soluble fumarate or an electrode acceptor. Libraries >33,000 unique insertions and average 9 insertions/kb allowed assessment each gene's fitness in a single experiment. Mutations 1,214 different genomic features impaired growth fumarate, significance 270 genes unresolved annotation due presence one more functional homologs was determined. Tn-Seq analysis -0.1 V versus standard hydrogen (SHE) electrode-grown cells identified mutations subset encoding cytochromes, processing systems proline-rich proteins, sensory networks, structures, polysaccharides, metabolic enzymes caused at least 50% apparent rate. Scarless deletion mutants select via revealed new putative porin-cytochrome conduit complex (extABCD) crucial electrodes, which not required Fe(III) oxide reduction. In addition, four lacking components methyl-accepting chemotaxis-cyclic dinucleotide sensing network (esnABCD) were defective colonization but grew normally These results suggest G. possesses distinct mechanisms recognition, colonization, electrodes compared oxides.IMPORTANCE Since insoluble, hypothesis sense reduce metals using same molecular used form biofilms produce electricity. However, simultaneously comparing thousands transposon undergoing electrode-dependent discovered cytochromes chemosensory supporting respiration. supports emerging model where recognizes surfaces forms conductive from those findings provide possible explanation studies correlate electricity generation syntrophic interspecies transfer reveal many previously unrecognized targets engineering this useful capability organisms.