Improving Understanding of Microbial Interactions with the Environment

The Science

Transporter proteins control the flow of large and small molecules in and out of the cell and are a primary means for organisms to interface with the environment. Transporters affect cellular metabolic capabilities and influence signaling pathways and regulatory networks that are key to the cell’s behavior. DOE researchers have confirmed the efficacy of a high-throughput methodology to rapidly and specifically identify the molecules transported by these proteins. The new technique measures the change in the melting temperature of proteins. Using Rhodopseudomonas palustris as a test case, they found a variety of compounds bound to the transporters studied that were not predicted using standard computational methods. These findings illustrate the potential of this method to expand the ability to predict the response of microbes and cells to environmental changes, such as the utilization of environmental nutrients and the ejection of toxic compounds.

The Impact

To improve the utility of the functional annotation for ABC transporters, researchers expressed and purified the set of solute binding proteins from Rhodopseudomonas palustris and characterized their ligand-binding specificity. Their approach utilized ligand libraries consisting of environmental and cellular metabolic compounds, and fluorescence thermal shift based high throughput ligand binding screens. This process resulted in the identification of specific binding ligands for approximately 64% of the purified and screened proteins. The collection of binding ligands is representative of common functionalities associated with many bacterial organisms as well as specific capabilities linked to the ecological niche occupied by R. palustris.


Giuliani, S. E., A. M. Frank, D. M. Corgliano, C. Seifert, L. Hauser, and F. R. Collart. 2011. “Environment Sensing and Response Mediated by ABC Transporters,” BMC Genomics 12, S8. DOI: 10.1186/1471-2164-12-S1-S8.