Insights into Transport of Lignin-Degradation Compounds in Biofuel-Producing Microbes
Understanding how lignin degradation compounds are transported into microbial cells for further processing into biofuels and for other biotechnology purposes is essential. Using the bacterium Rhodopseudomonas palustris as a model to study the transport of these compounds, researchers from Argonne and Brookhaven national laboratories have applied high-throughput genomic and biophysical approaches to determine the characteristics of the proteins that bind the lignin-degradation products. These binding proteins are part of a large complex, the ABC transporter, that moves chemical compounds through the cell membrane into the cell. The researchers found that the proteins bind aromatic compounds with high affinity and tested the physical configuration of these binding proteins with and without the aromatic degradation products present. The results suggested that the shape of the proteins does not change, but that local changes do occur in the tertiary structure where degradation compounds bind. This molecular reconfiguration could position the aromatic compounds to be more easily transported through the cell membrane. The combination of theoretical models validated by these studies and experimental approaches should be applicable to other organisms relevant to biofuels research.
Pietri, R., S. Zerbs, D. Corgliano, M. Allaire, F. Collart, and L. Miller. 2012. “Biophysical and Structural Characterization of a Sequence-Diverse Set of Solute-Binding Proteins for Aromatic Compounds,” Journal of Biological Chemistry 287, 23748-56. DOI: 10.1074/jbc.M112.352385.