From Boyce Thompson Institute:
IMAGE: This is a TEM image of the algae C. reinhardtii. view more
Credit: Photo courtesy of Mary Morphew and J. Richard McIntosh via the Cell Image Library.
ITHACA, NY–A new way of fixing inactive proteins has been discovered in an algae, which uses chloroplast extracts and light to release an interrupting sequence from a protein.
Research specialist Stephen Campbell and Professor David Stern at the Boyce Thompson Institute report the discovery in the July 29 issue of the Journal of Biological Chemistry. This repair system may have applications in agriculture and biotechnology because it could potentially be harnessed to enable proteins to become active only in the light.
Many proteins contain extra sequences, called insertions, that can disrupt their function. The current paper demonstrates that the algae Chlamydomonas reinhardtii has the necessary toolkit to repair proteins by removing these insertions.
Campbell discovered this new repair system while purifying a protein from the chloroplasts of C. reinhardtii that can cut RNA. Upon sequencing the protein, he identified it as RB47, a protein that was not known to have any RNA-cleaving ability. Campbell noticed that the middle of the protein was missing. When he compared the protein sequence to its corresponding gene sequence, the protein was much shorter than expected.
Upon further study, Campbell found that he could detect a long version of the protein that contained an insertion and a short version that didn’t. The cells make both versions when grown in the light or the dark, but only the short version can cleave RNA. The long version of the protein could be converted into the short one by mixing it in a test tube with chloroplasts from cells grown in the light and by illuminating the reaction. This process removed the interrupting …