Carbonic anhydrase is an enzyme which catalyzes the interconversion of the two forms of inorganic carbon, carbon dioxide and bicarbonate ion, which predominate under physiological conditions. In various species of unicellular green algae, including Chlamydomonas reinhardtii, one or more forms of carbonic anhydrase are critical components of an inorganic carbon concentrating system which allows these organisms to efficiently utilize the low levels of ambient carbon dioxide which would otherwise limit their growth. This project investigates the nature of the structure of the extracellular form of carbonic anhydrase in Chlamydomonas reinhardtii in vivo an in vitro and examines the effect of this structure on the catalytic properties of the enzyme. The localization of the extracellular enzyme in C. reinhardtii will be more clearly defined by chemical cross- linking and direct cellular binding studies. In addition, the stabilization, purification and localization of the intracellular form(s) of the enzyme will be investigated. These studies are critical in terms of identifying the components, and describing the details of the mechanism by which Chlamydomonas reinhardtii is able to efficiently concentrate inorganic carbon to provide carbon dioxide for photosynthesis. It is potentially useful for improving photosynthetic capacity of crop plants.***//
