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Journal of photochemistry and photobiology. B, Biology

Impact of trifluoroethanol-induced structural changes on luciferase cleavage sites.


PMID 25662040

Abstract

Induction of structural changes in firefly luciferase were identified by proteolytic digestion, activity measurement and spectroscopic tools upon treatment with 2,2,2-trifluoroethanol (TFE). Our results show that the conformation and function of luciferase change according to TFE concentration. Limited addition of TFE (below 10%) alters the tertiary structure and proteolytic rate with a similar digestion pattern, without noticeable changes in the secondary structure. Conformational changes result in loss of enzymatic activity. More addition of TFE (between 20% and 30%) disrupts the tertiary structure, and consequently the activity completely disappears without recovery upon dilution. Furthermore, at high protein concentration, significant aggregation is observed in this range of TFE concentration. A further increase in TFE concentration (above 30%) induces more helical structure, which is more resistant to tryptic attack. Overall, in spite of large conformational changes of luciferase induced by TFE, the prime-sites of proteolytic cleavage are still located at the same chain segments.