@article {3078,
	title = {A pilin chaperone required for the expression of electrically conductive Geobacter sulfurreducens pili.},
	journal = {Environ Microbiol},
	volume = {21},
	year = {2019},
	month = {2019 Jul},
	pages = {2511-2522},
	abstract = {<p>Mechanisms controlling the expression of the electrically conductive pili (e-pili) of Geobacter species are of interest because of the important role of e-pili in diverse biogeochemical processes, anaerobic digestion and electromicrobiological applications. We investigated the function of the protein, designated Spc (short pilin chaperone), encoded by the gene immediately downstream from the gene for PilA, the monomer that assembles into e-pili. Multiple lines of evidence suggest that Spc forms an oligomer that is associated with the inner membrane. Mutating the start codon of spc to prevent translation increased the transcript abundance of pilA but greatly diminished the abundance of PilA, and e-pili could no longer be detected. Cross-linking, protein capture and two-hybrid studies demonstrated that Spc and PilA interacted. Two sites in PilA for electrostatic interaction with Spc were identified. The results demonstrate that Spc is required for PilA stability prior to incorporation into e-pili, suggesting that Spc has a chaperone function that may be specific to the relatively short PilA monomers that assemble into e-pili. These results are important for identifying microorganisms likely to express e-pili from (meta)genomic data and for the construction of microbial strains expressing e-pili.</p>},
	keywords = {Electric Conductivity, Fimbriae Proteins, Fimbriae, Bacterial, Geobacter, Molecular Chaperones},
	issn = {1462-2920},
	doi = {10.1111/1462-2920.14638},
	author = {Liu, Xing and Zhan, Ji and Jing, Xianyue and Zhou, Shungui and Lovley, Derek R}
}
@article {3131,
	title = {A Geobacter sulfurreducens strain expressing pseudomonas aeruginosa type IV pili localizes OmcS on pili but is deficient in Fe(III) oxide reduction and current production.},
	journal = {Appl Environ Microbiol},
	volume = {80},
	year = {2014},
	month = {2014 Feb},
	pages = {1219-24},
	abstract = {<p>The conductive pili of Geobacter species play an important role in electron transfer to Fe(III) oxides, in long-range electron transport through current-producing biofilms, and in direct interspecies electron transfer. Although multiple lines of evidence have indicated that the pili of Geobacter sulfurreducens have a metal-like conductivity, independent of the presence of c-type cytochromes, this claim is still controversial. In order to further investigate this phenomenon, a strain of G. sulfurreducens, designated strain PA, was constructed in which the gene for the native PilA, the structural pilin protein, was replaced with the PilA gene of Pseudomonas aeruginosa PAO1. Strain PA expressed and properly assembled P. aeruginosa PilA subunits into pili and exhibited a profile of outer surface c-type cytochromes similar to that of a control strain expressing the G. sulfurreducens PilA. Surprisingly, the strain PA pili were decorated with the c-type cytochrome OmcS in a manner similar to the control strain. However, the strain PA pili were 14-fold less conductive than the pili of the control strain, and strain PA was severely impaired in Fe(III) oxide reduction and current production. These results demonstrate that the presence of OmcS on pili is not sufficient to confer conductivity to pili and suggest that there are unique structural features of the G. sulfurreducens PilA that are necessary for conductivity.</p>},
	keywords = {Amino Acid Sequence, Cytochromes c, Electricity, Ferric Compounds, Fimbriae Proteins, Fimbriae, Bacterial, Geobacter, Methanosarcinaceae, Molecular Sequence Data, Oxidation-Reduction, Pseudomonas aeruginosa, Sequence Alignment},
	issn = {1098-5336},
	doi = {10.1128/AEM.02938-13},
	author = {Liu, Xing and Tremblay, Pier-Luc and Malvankar, Nikhil S and Nevin, Kelly P and Lovley, Derek R and Vargas, Madeline}
}
