Australian National University.
Ribulose-1,5-bisphospate carboxylase/oxygenase (Rubisco) serves as a gateway for inorganic carbon to enter metabolic pathways in most ecosystems on Earth. As the performance of Rubisco can greatly affect crop yield, substantial efforts have been made to study its structure and function. However despite substantial progress over the past few decades, better enzymes for crops are yet to be delivered. Recent findings showed that Rubisco properties are continually being adjusted by natural selection to better fit gaseous and thermal environments the enzyme is found at in different species. Human mediated artificial selection has created a vast variety of crop cultivars in relatively short time. Many crops nowadays are grown in climates different from the ones experienced by their ancestors, and hence Rubisco possessed by some of modern crop cultivars might not be optimal for the conditions it experiences. Thus there is a potential for artificial improvement of crop Rubiscos to better fit new climates as well as for new faster and/or more specific crop Rubiscos resulting in increase of the global crop yield. We analysed sequences of genes encoding the large subunits of Rubisco, where the active sites are located, for amino acid replacements that may be responsible for changes in Rubisco properties. However, these replacements could be lineage specific and produce different results in different plant species. So, further we assessed possibility of assembly of foreign Rubisco large subunits from major cereal, legume, tuberous and vegetable crops with tobacco small subunits in tobacco plants. The effects of particular amino acid replacements on Rubisco kinetics and ability of foreign Rubisco large subunits assembly with tobacco small subunits are discussed.