Iodine is considered an essential element for all vertebrates and is also beneficial in moderate concentrations for plants, although its role in plants has not yet been sufficiently studied. For vertebrates, it is a crucial part of the thyroid hormones T3 and T4. Even though the presence of thyroid hormone analogues in plants has been confirmed, the mechanism of their synthesis and their role in plants are not yet fully understood.
Considering the characteristics of hormonogenic pairs of iodinated tyrosine amino acid residues in thyroglobulin, we chose plant proteins from the mouse-ear cress (Arabidopsis thaliana) that contain pairs of tyrosine amino acid residues with similar characteristics. We tried to insert sequences encoding two of these plant proteins into an expression vector for expression in E. coli. Sequence encoding DNA-directed RNA polymerases II, IV and V subunit 8B (Rpb8) was successfully cloned, and the recombinant protein was expressed and purified via Ni$^{2+}$ affinity chromatography. The purified protein was chemically iodinated, which caused it to aggregate.
|
