@article {3116,
	title = {Visualization of charge propagation along individual pili proteins using ambient electrostatic force microscopy.},
	journal = {Nat Nanotechnol},
	volume = {9},
	year = {2014},
	month = {2014 Dec},
	pages = {1012-7},
	abstract = {<p>The nanoscale imaging of charge flow in proteins is crucial to understanding several life processes, including respiration, metabolism and photosynthesis. However, existing imaging methods are only effective under non-physiological conditions or are limited to photosynthetic proteins. Here, we show that electrostatic force microscopy can be used to directly visualize charge propagation along pili of Geobacter sulfurreducens with nanometre resolution and under ambient conditions. Charges injected at a single point into individual, untreated pili, which are still attached to cells, propagated over the entire filament. The mobile charge density in the pili, as well as the temperature and pH dependence of the charge density, were similar to those of carbon nanotubes and other organic conductors. These findings, coupled with a lack of charge propagation in mutated pili that were missing key aromatic amino acids, suggest that the pili of G. sulfurreducens function as molecular wires with transport via delocalized charges, rather than the hopping mechanism that is typical of biological electron transport.</p>},
	keywords = {Fimbriae Proteins, Fimbriae, Bacterial, Geobacter, Microscopy, Electrochemical, Scanning},
	issn = {1748-3395},
	doi = {10.1038/nnano.2014.236},
	author = {Malvankar, Nikhil S and Yalcin, Sibel Ebru and Tuominen, Mark T and Lovley, Derek R}
}
@article {535,
	title = {Extracellular electron transfer via microbial nanowires.},
	journal = {Nature},
	volume = {435},
	year = {2005},
	month = {2005 Jun 23},
	pages = {1098-101},
	abstract = {Microbes that can transfer electrons to extracellular electron acceptors, such as Fe(iii) oxides, are important in organic matter degradation and nutrient cycling in soils and sediments. Previous investigations on electron transfer to Fe(iii) have focused on the role of outer-membrane c-type cytochromes. However, some Fe(iii) reducers lack c-cytochromes. Geobacter species, which are the predominant Fe(iii) reducers in many environments, must directly contact Fe(iii) oxides to reduce them, and produce monolateral pili that were proposed, on the basis of the role of pili in other organisms, to aid in establishing contact with the Fe(iii) oxides. Here we report that a pilus-deficient mutant of Geobacter sulfurreducens could not reduce Fe(iii) oxides but could attach to them. Conducting-probe atomic force microscopy revealed that the pili were highly conductive. These results indicate that the pili of G. sulfurreducens might serve as biological nanowires, transferring electrons from the cell surface to the surface of Fe(iii) oxides. Electron transfer through pili indicates possibilities for other unique cell-surface and cell-cell interactions, and for bioengineering of novel conductive materials.},
	keywords = {Biotechnology, Electric Conductivity, Electron Transport, Ferric Compounds, Fimbriae Proteins, Fimbriae, Bacterial, Genes, Bacterial, Geobacter, Microscopy, Atomic Force, Microscopy, Electron, Transmission, Mutation, Nanostructures, Phylogeny},
	issn = {1476-4687},
	doi = {10.1038/nature03661},
	author = {Reguera, Gemma and McCarthy, Kevin D and Mehta, Teena and Nicoll, Julie S and Tuominen, Mark T and Lovley, Derek R}
}
