Basis of Microbial Membrane Attachment to Mineral Surfaces
and Ionic Contaminants Uptake
EMSL Project ID
19842
Abstract
Allocation of resources at EMSL facilities, both experimental and computational, is sought for the extension of our current DOE-funded biogeochemistry project. The project focus lies on the molecular level description of the attachment of Gram-negative microbial membranes to mineral surfaces and the interactions with subsurface contaminants. An accurate and consistent molecular model of the rough lipopolysaccharide (LPS) bacterial membrane of Pseudomonas aeruginosa has been previously developed, validated against experimental data and its structural and electrostatic properties characterized. This model has also been used to study the interactions between the LPS membrane and a goethite nanocrystal. At this stage, attachment of the LPS membrane to mineral surfaces will be modeled and the corresponding molecular interactions characterized. In addition, relative affinities to different mineral surfaces and sorption ability of uranium, in the form of uranyl - a DOE-relevant ionic contaminant, by the bacterial membrane will be probed. Development and validation of classical parameters for mineral surfaces (hematite and goethite) and uranyl are currently on-going. These parameters will be used in conjunction with potential of mean force-driven free-energy calculations to estimate the uranyl sorption ability by the LPS membrane. The results will be compared to the relative affinities for a variety of other ionic species previously determined by Dr. Erich Vorpagel at PNNL. Microbial membrane binding/unbinding to mineral surfaces will be calibrated against biological force microscopy (BFM) data generated for the exact same system in silico. BFM is an elegant variation of traditional atomic force microscopy (AFM) that allows directly probing the dynamic interface between a living microorganism and a mineral surface in force energy and distancing nanospace. This capability was originally developed by a collaboration of Dr. Brian Lower at PNNL with researchers of the Ohio State University. It consists of a single bacterium or a bacteria-coated bead linked to a force cantilever, thereby creating a biologically-active-force-probe. The probe is then used in an atomic force microscope to quantitatively measure attractive and repulsive forces in the nano- to pico-Newton range as a function of the mineral-probe distance, typically at the nanometer scale. BFM has been previously used to quantitatively study interfacial and adhesion forces between Gram-negative bacteria and mineral or man-made surfaces. In these studies the measured forces of binding between the bacterium and the material surface has been largely attributed to proteins exposed on the surface of the bacterium. Since surface-exposed proteins are very large molecules they act overprinting the interactions that may be occurring between smaller molecules, such as LPS, and the mineral surfaces.
Project Details
Project type
Large-Scale EMSL Research
Start Date
2006-08-24
End Date
2009-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members
Related Publications
Bose, S, M. F. Hochella Jr., Y. A. Gorby, D. W. Kennedy, D. E. McCready, A. S. Madden, and B. H. Lower. 2009. "Bioreduction of hematite nanoparticles by the dissimilatory iron reducing bacterium Shewanella oneidensis MR-1." Geochimica et Cosmochimica Acta 73: 962-976.
Brian H. Lower, Liang Shi, Ruchi Yongsunthon, Timothy C. Droubay, David E. McCready, and Steven K. Lower (2007). “Specific bonds between an iron oxide surface and outer membrane cytochromes MtrC and OmcA from Shewanella oneidensis MR-1,” J. Bacteriol. 189:4944-4952.
Brian H. Lower, Roberto D. Lins, Tjerk P. Straatsma, Michael F. Hochella Jr., and Steven K. Lower (2007). "In vitro evolution of a peptide with a hematite binding motif," Nano Lett.: In review.
Lower BH, RD Lins, ZW Oestreicher, TP Straatsma, MF Hochella Jr., L Shi, and SK Lower. 2008. "In Vitro Evolution of a Peptide with a Hematite Binding Motif That May Constitute a Natural Metal-Oxide Binding Archetype ." Environmental Science & Technology 42(10):3821-3827. doi:10.1021/es702688c
Lower B. H., R. Yongsunthon, L. Shi, L. Wildling, H. J. Gruber, N. S. Wigginton, C. L. Reardon, G. E. Pinchuk, T. C. Droubay, J-F. Boily, and S. K. Lower. 2009. "Antibody Recognition Force Microscopy Shows that Outer Membrane Cytochromes OmcA and MtrC Are Expressed on the Exterior Surface of Shewanella oneidensis MR-1." Applied and Environmental Microbiology 75:2931-2935.
Nicholas S. Wigginton, Kevin M. Rosso, Brian H. Lower, Liang Shi, and Michael F. Hochella, Jr. (2007). “Scanning Tunneling Microscopy and Spectroscopy of Bacterial Outer Membrane Cytochromes,” Geochim. et Cosmochim. Acta 71:543-555.
Saumyaditya Bose, Michael F. Hochella Jr., Yuri A. Gorby, David W. Kennedy, David E. McCready, Andrew S. Madden, and Brian H. Lower (2009). Bioreduction of Hematite Nanoparticles by the Dissimilatory Iron Reducing Bacterium Shewanella oneidensis MR-1. Geochimica et Cosmochimica Acta (in press).