Russian scientists come up with proteins sensitive to low doses of radiation

MOSCOW, July 12. /TASS/ A research team from Institute of Biophysics Siberian Branch of RAS, Krasnoyarsk State Agrarian University, Siberian Federal University (SFU), and Lomonosov Moscow State University has formulated a protein complex sensitive to radiation, the press office of SFU said.

The brand-new compound shows photoluminescence properties, with its emission spectrum being affected even by low-dose radiation. The scientific paper has been published recently in Analytical and Bioanalytical Chemistry.

"The study addresses the application of fluorescent coelenteramide-containing proteins as color bioindicators for radiotoxicity evaluation. The high sensitivity of the protein-based test system to low-dose ionizing radiation of tritium has been demonstrated," the research article stated.

Sensitive substance

The protein complex which is the basis for the biosensor functioning is called 'obelin' as it is extracted from the luminescent marine coelenterate 'Obelia longissimi'. Under irradiation by external light, obelin shows luminescence, that is, it emits light by itself in a broad frequency domain from purple to sea-green.

The character of luminescence - the spectrum of emitted light - depends strongly on the surrounding of protein molecules. That is why the researchers have suggested using obelin for biotesting various toxic effects, in particular, the radiation impact.

The color purple

As a source of radiation, scientists applied "heavy water" containing, instead of normal hydrogen, tritium, which is a heavy and unstable isotope of hydrogen which emits the flow of high-energy electron in the course of decay. During the experiment, various protein systems with obelin were exposed to such radiation for 18 days. As a result, it was revealed in each particular case, that under radiation, obelin changed its emission spectrum by acquiring more purple color in it.

Apart from possible application benefits, the researchers emphasize that their study might also shed light on the still vague physical-chemical mechanisms of toxicity of low radioactive irradiation. For example, the typical shift of luminescence from sea-green to purple part might demonstrate the changes in the spatial configuration of protein under the impact of high-energy electrons.