Scripps Research Team Elucidates Structure of UV Protection Molecule in Plants

In 2002, scientists from the Scripps Research Institute discovered that plants have developed "natural sunscreen" controlled by a ultra violet-sensing protein molecule named UVR8. In a follow up study together with scientists at the University of Glasgow, they were able to determine the molecular architecture of UVR8, including the 3D arrangement of its atoms. The researchers produced and purified copies of UVR8 and chemically induce it to crystallize. Then the crystallized molecule was fired with X-rays to analyze its diffracttion pattern. They also confirmed that UVR8 can sense UV-B light on its own by altering amino acids in the molecule.

"Tryptophans in the pyramid structure turned out to be crucial for UV-B detection; in fact, amino-acid substitution of one tryptophan by a phenylalanine shifts the sensitivity of UVR8 to shorter-wavelength UV-C radiation," they reported. The next step of the researchers would be to find out more precisely how the absorption of UV-B causes the disassociation of the UVR8 dimer, and then how the separated subunits interact with other proteins and chromosomes in the nucleus to switch on protective responses in the plant.

For more details about the study, contact mikaono@scripps.edu.