skip to main content
DOE PAGES title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Significance of a Posttranslational Modification of the PilA Protein of Geobacter sulfurreducens for Surface Attachment, Biofilm Formation, and Growth on Insoluble Extracellular Electron Acceptors

Abstract

ABSTRACT Geobacter sulfurreducens, an anaerobic metal-reducing bacterium, possesses type IV pili. These pili are intrinsic structural elements in biofilm formation and, together with a number ofc-type cytochromes, are thought to serve as conductive nanowires enabling long-range electron transfer (ET) to metal oxides and graphite anodes. Here, we report that a posttranslational modification of a nonconserved amino acid residue within the PilA protein, the structural subunit of the type IV pili, is crucial for growth on insoluble extracellular electron acceptors. Matrix-assisted laser desorption ionization (MALDI) mass spectrometry of the secreted PilA protein revealed a posttranslational modification of tyrosine-32 with a moiety of a mass consistent with a glycerophosphate group. Mutating this tyrosine into a phenylalanine inhibited cell growth with Fe(III) oxides as the sole electron acceptor. In addition, this amino acid substitution severely diminished biofilm formation on graphite surfaces and impaired current output in microbial fuel cells. These results demonstrate that the capability to attach to insoluble electron acceptors plays a crucial role for the cells' ability to utilize them. The work suggests that glycerophosphate modification of Y32 is a key factor contributing to the surface charge of type IV pili, influencing the adhesion ofGeobacterto specific surfaces. IMPORTANCEType IV pili aremore » bacterial appendages that function in cell adhesion, virulence, twitching motility, and long-range electron transfer (ET) from bacterial cells to insoluble extracellular electron acceptors. The mechanism and role of type IV pili for ET inGeobacter sulfurreducensis still a subject of research. In this study, we identified a posttranslational modification of the majorG. sulfurreducenstype IV pilin, suggested to be a glycerophosphate moiety. We show that a mutant in which the glycerophosphate-modified tyrosine-32 is replaced with a phenylalanine has reduced abilities for ET and biofilm formation compared with those of the wild type. The results show the importance of the glycerophosphate-modified tyrosine for surface attachment and electron transfer in electrode- or Fe(III)-respiringG. sulfurreducenscells.« less

Authors:
; ; ; ;
Publication Date:
Research Org.:
Univ. of Massachusetts, Amherst, MA (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1536861
Grant/Contract Number:  
FC02-02ER63446
Resource Type:
Accepted Manuscript
Journal Name:
Journal of Bacteriology
Additional Journal Information:
Journal Volume: 199; Journal Issue: 8; Journal ID: ISSN 0021-9193
Publisher:
American Society for Microbiology
Country of Publication:
United States
Language:
English
Subject:
Microbiology

Citation Formats

Richter, Lubna V., Franks, Ashley E., Weis, Robert M., Sandler, Steven J., and O'Toole, George. Significance of a Posttranslational Modification of the PilA Protein of Geobacter sulfurreducens for Surface Attachment, Biofilm Formation, and Growth on Insoluble Extracellular Electron Acceptors. United States: N. p., 2017. Web. doi:10.1128/jb.00716-16.
Richter, Lubna V., Franks, Ashley E., Weis, Robert M., Sandler, Steven J., & O'Toole, George. Significance of a Posttranslational Modification of the PilA Protein of Geobacter sulfurreducens for Surface Attachment, Biofilm Formation, and Growth on Insoluble Extracellular Electron Acceptors. United States. doi:10.1128/jb.00716-16.
Richter, Lubna V., Franks, Ashley E., Weis, Robert M., Sandler, Steven J., and O'Toole, George. Mon . "Significance of a Posttranslational Modification of the PilA Protein of Geobacter sulfurreducens for Surface Attachment, Biofilm Formation, and Growth on Insoluble Extracellular Electron Acceptors". United States. doi:10.1128/jb.00716-16. https://www.osti.gov/servlets/purl/1536861.
@article{osti_1536861,
title = {Significance of a Posttranslational Modification of the PilA Protein of Geobacter sulfurreducens for Surface Attachment, Biofilm Formation, and Growth on Insoluble Extracellular Electron Acceptors},
author = {Richter, Lubna V. and Franks, Ashley E. and Weis, Robert M. and Sandler, Steven J. and O'Toole, George},
abstractNote = {ABSTRACT Geobacter sulfurreducens, an anaerobic metal-reducing bacterium, possesses type IV pili. These pili are intrinsic structural elements in biofilm formation and, together with a number ofc-type cytochromes, are thought to serve as conductive nanowires enabling long-range electron transfer (ET) to metal oxides and graphite anodes. Here, we report that a posttranslational modification of a nonconserved amino acid residue within the PilA protein, the structural subunit of the type IV pili, is crucial for growth on insoluble extracellular electron acceptors. Matrix-assisted laser desorption ionization (MALDI) mass spectrometry of the secreted PilA protein revealed a posttranslational modification of tyrosine-32 with a moiety of a mass consistent with a glycerophosphate group. Mutating this tyrosine into a phenylalanine inhibited cell growth with Fe(III) oxides as the sole electron acceptor. In addition, this amino acid substitution severely diminished biofilm formation on graphite surfaces and impaired current output in microbial fuel cells. These results demonstrate that the capability to attach to insoluble electron acceptors plays a crucial role for the cells' ability to utilize them. The work suggests that glycerophosphate modification of Y32 is a key factor contributing to the surface charge of type IV pili, influencing the adhesion ofGeobacterto specific surfaces. IMPORTANCEType IV pili are bacterial appendages that function in cell adhesion, virulence, twitching motility, and long-range electron transfer (ET) from bacterial cells to insoluble extracellular electron acceptors. The mechanism and role of type IV pili for ET inGeobacter sulfurreducensis still a subject of research. In this study, we identified a posttranslational modification of the majorG. sulfurreducenstype IV pilin, suggested to be a glycerophosphate moiety. We show that a mutant in which the glycerophosphate-modified tyrosine-32 is replaced with a phenylalanine has reduced abilities for ET and biofilm formation compared with those of the wild type. The results show the importance of the glycerophosphate-modified tyrosine for surface attachment and electron transfer in electrode- or Fe(III)-respiringG. sulfurreducenscells.},
doi = {10.1128/jb.00716-16},
journal = {Journal of Bacteriology},
number = 8,
volume = 199,
place = {United States},
year = {2017},
month = {1}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Save / Share:

Works referenced in this record:

Extracellular electron transfer via microbial nanowires
journal, June 2005

  • Reguera, Gemma; McCarthy, Kevin D.; Mehta, Teena
  • Nature, Vol. 435, Issue 7045, p. 1098-1101
  • DOI: 10.1038/nature03661

Extracellular reduction of uranium via Geobacter conductive pili as a protective cellular mechanism
journal, September 2011

  • Cologgi, D. L.; Lampa-Pastirk, S.; Speers, A. M.
  • Proceedings of the National Academy of Sciences, Vol. 108, Issue 37, p. 15248-15252
  • DOI: 10.1073/pnas.1108616108

Alignment of the c-Type Cytochrome OmcS along Pili of Geobacter sulfurreducens
journal, April 2010

  • Leang, C.; Qian, X.; Mester, T.
  • Applied and Environmental Microbiology, Vol. 76, Issue 12, p. 4080-4084
  • DOI: 10.1128/AEM.00023-10

Type IV Pilus Structure by Cryo-Electron Microscopy and Crystallography: Implications for Pilus Assembly and Functions
journal, September 2006


Genome of Geobacter sulfurreducens: Metal Reduction in Subsurface Environments
journal, December 2003

  • Methe, B. A.; Nelson, K. E.; Eisen, J. A.
  • Science, Vol. 302, Issue 5652, p. 1967-1969
  • DOI: 10.1126/science.1088727

Possible Nonconductive Role of Geobacter sulfurreducens Pilus Nanowires in Biofilm Formation
journal, December 2006

  • Reguera, G.; Pollina, R. B.; Nicoll, J. S.
  • Journal of Bacteriology, Vol. 189, Issue 5, p. 2125-2127
  • DOI: 10.1128/JB.01284-06

Development of a Genetic System for Geobacter sulfurreducens
journal, July 2001


Selection of a variant of Geobacter sulfurreducens with enhanced capacity for current production in microbial fuel cells
journal, August 2009

  • Yi, Hana; Nevin, Kelly P.; Kim, Byoung-Chan
  • Biosensors and Bioelectronics, Vol. 24, Issue 12, p. 3498-3503
  • DOI: 10.1016/j.bios.2009.05.004