Researchers relied on an X-ray-based technique known as “footprinting” to pinpoint the chemical connections between the bacterial protein and nanoparticles composed of iron and oxygen. The study identified a previously mapped, surprisingly small and weak binding site, but unknown was how the site bound to the metal-containing mineral because conventional techniques can’t see this binding process. Footprinting reveals interactions of proteins in a near-native environment. The protein selected for the study is from the metal-reducing bacterium Shewanella oneidensis, which “eats sugar and basically breathes minerals” when oxygen is unavailable. This study already is providing ideas on how to redesign these proteins to make better electronic connections and thus more sensitive bioelectronic sensors.
Fukushima, T., et al. “The Molecular Basis for Binding of an Electron Transfer Protein to a Metal Oxide Surface.” J. Am. Chem. Soc. 139(36), 12647–12654, (2017). [DOI:10.1021/jacs.7b06560].
Instruments and Facilities Used: X-ray beamline 5.3.1 of the Advanced Light Source (ALS) to perform “footprinting” and mass spectrometry at the Biological Nanostructures Facility at the Molecular Foundry, both at Lawrence Berkeley National Laboratory (LBNL), and the LBNL-led DOE Joint BioEnergy Institute.
Funding Acknowledgements: Work supported by the Laboratory Directed Research and Development Program of Lawrence Berkeley National Laboratory (LBNL), performed at the Molecular Foundry and Advanced Photon Source (APS) at Argonne National Laboratory (ANL) and used resources of the Joint BioEnergy Institute (JBEI), supported by the Office of Basic Energy Sciences (OBES) and Office of Biological and Environmental Research (OBER), U.S. Department of Energy (DOE) Office of Science, under Contract No. DE-AC02-05CH11231. CMA-F support: Office of Naval Research, Award number N000141310551.