March 26, 2012

ANN ARBOR, Mich. ­– University of Michigan biochemists and research colleagues from the Massachusetts Institute of Technology believe there may much to learn from nature when it comes to developing future sources of energy.

In their recently published paper in the journal Nature, the researchers use X-Ray crystallography of the associated complex between two key enzymes to offer a unique look at a reaction that plays an important role in energy metabolism and the environment.  The two proteins within the complex collaborate in a biological process that scrubs carbon monoxide from the atmosphere as the microbes use this toxic gas as a source of carbon and energy. This pathway also allows microbes to make their cellular carbon from the greenhouse gas, carbon dioxide.  The biological process occurs in many anaerobic environments, including the digestive tracts of humans and other organisms. The team’s work offers fresh insights into liquid fuel production.

This image depicts the vitamin B12 in motion as it is carried in large conformational movements by the protein from its initial resting position towards its active position above the folate, shown in blue. The spheres represent the cobalt atom of B12 and the grey, green and yellow stick figures represent the B12 in transit in different trapped crystal structures.

“Engineering of this pathway is being considered by various research groups in industry and academics as a means for the utilization of natural and synthetic sources of H2, CO2 and CO to generate liquid fuels and chemicals,” said U-M Professor of Biological Chemistry Stephen Ragsdale, a contributor to the paper and faculty affiliate of the University of Michigan Energy Institute. “The pathway is remarkable in the novel way that it stiches together one-carbon compounds to generate a chemical intermediate, acetyl-CoA, that is central to the production of many of the components of the cell, as well as industrially important chemicals. This paper provides an understanding of the remarkable conformational movements that occur during one of the key steps in this microbial process.”

Read more about the team’s findings.