Bacterial microcompartments and carbon chemistry: Structure of the carboxysome and its function in CO2 capture

FUEL 181

Cheryl A. Kerfeld, ckerfeld@lbl.gov1, Fei Cai2, Todd O. Yeates3, Gordon C. Cannon2, and Sabine Heinhorst2. (1) Plant and Microbial Biology, Department of Energy Joint Genome Institute and University of California, Berkeley, DOE JGI, 2800 Mitchell Drive, Walnut Creek, CA 94598, (2) Department of Biochemistry, University of Southern Mississippi, (3) Molecular Biology Institute, University of California, Los Angeles
Cyanobacteria and many chemoautotrophic microbes have evolved a special mechanism for dramatically enhancing CO2 fixation. In these organisms, tens of thousands of molecules of RuBisCO are packaged inside subcellular microcompartments called the carboxysome. The carboxysome shell resembles a viral capsid, being assembled from many copies of nearly identical small protein subunits. By sequestering RuBisCO together with carbonic anhydrase activity, the carboxysome provides an environment for enhanced CO2 fixation. Ongoing crystallographic studies on carboxysomes found in cyanobacteria and chemoautotrophs provide the first structural insights into carboxysome assembly and function, and new insights into how carboxysome architecture enhances RuBisCO activity by allowing selective transport of metabolites across the shell. In parallel, bioinformatic approaches have revealed that the carboxysome is just one example of a surprisingly widespread strategy for biological compartmentalization of diverse carbon chemistry. The combination of bioinformatics and structural biology is aimed at elucidating the structural basis of this functional diversity.
 

Hybrid Nanotechnologies for an Enhanced CO2 Fixation
8:50 AM-11:45 AM, Wednesday, April 9, 2008 Morial Convention Center -- Rm. 240/241, Oral

Division of Fuel Chemistry

The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008