Very little is known about the role of iodine in plants. Iodine is predominantly present in plants in the form of iodide (I-), but some is bound to organic molecules. The addition of iodine in cultivation increases the biomass of the plant and accelerates the flowering time. Some of the proteins in Arabidopsis thaliana have iodinated tyrosine residues. These include RuBisCO activase, a chloroplast enzyme that belongs to the group of catalytic chaperones. It is an ATPase that changes the conformation of the RuBisCO enzyme from a closed to an open conformation and thus enables the release of an inhibitory molecule from the active site.
The aim of our work was to express and isolate a soluble protein of RuBisCO activase (from Arabidopsis thaliana) in a bacterial expression system. We wanted to express the protein in two lengths: a standard version and a truncated version. In the truncated version, 35 amino acid residues were removed from the C-terminus. First, we prepared a phagemid with a truncated sequence for RuBisCO activase. Then both versions of the protein were expressed, isolated and purified by nickel affinity chromatography.
We found that the RuBisCO activase protein can be produced using a bacterial expression system. However, we were only able to express RuBisCO activase in sufficient quantities for further studies, while the expression of the truncated version was not effective. In the future, we should optimise the whole process of expressing the truncated version of RuBisCO activase.
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