News and Publications - Research Highlight
Grand Challenge Research Uses a Systems Biology Approach
The crystal structures of CmpA (red) and NrtA (blue) were discovered to be unusual and similar. CmpA and NrtA bind and transport across the membrane two important nutrients: carbon (via bicarbonate transport by CmpA) and nitrogen (via nitrate transport by NrtA).
Environmental Molecular Sciences Laboratory (EMSL) Scientific Grand Challenges are an innovative approach to solving complex, large-scale, scientific and engineering problems with broad scientific and environmental or economic impact. They have available to them resources housed in all of EMSL’s six facilities and rely upon the collaborative research efforts of scientists from multiple institutions.
The EMSL Scientific Grand Challenge Membrane Biology team is using a systems biology approach to understand the network of genes and proteins that govern the structure and function of membranes and their components responsible for photosynthesis and nitrogen fixation in cyanobacteria (also called blue-green algae). Knowledge gained by studying photosynthesis and nitrogen fixation can be applied to issues of environmental sustainability, including:
- improvements in solar energy conversion
- planetary carbon sequestration through carbon dioxide assimilation
- improved understanding of biofuel production
- metal assimilation and immobilization.
Members of the Membrane Biology team recently published the first journal article to result from EMSL Scientific Grand Challenge research. In the June issue of Proceedings of the National Academy of Sciences of the United States of America, researchers describe the first structure determined for a nitrate receptor, that of NrtA in a species of cyanobacteria. NrtA represents a previously uncharacterized class of transport proteins, and its closest homologue is CmpA, a bicarbonate-binding protein found in several species of cyanobacteria. The similarity of NrtA to other nitrate and bicarbonate receptors sheds light on the possible differences between nitrate and bicarbonate binding and reveals a previously unknown link between nitrate and bicarbonate uptake in cyanobacteria.
The EMSL Grand Challenge Membrane Biology team is led by Himadri Pakrasi from Washington University in St. Louis and includes researchers from Saint Louis University, Donald Danforth Plant Science Center, Purdue University, Shanghai Institutes for Biological Sciences Institute of Plant Physiology and Ecology, and Pacific Northwest National Laboratory.
Reference
Koropatkin NM, HB Pakrasi, and TJ Smith. 2006. “Atomic Structure of a Nitrate-Binding Protein Crucial for Photosynthetic Productivity.” Proceedings of the National Academy of Sciences of the United States of America 103(26):9820-9825.