Study of Changes in Folding/unfolding Properties and Stability of MYB12 Transcription Factor Following UV-B Exposure
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Flavonoids mostly protect plant cells from the harmful effects of UV-B radiation from the sun. In plants, the R2R3-subfamily of the MYB transcription factor, MYB12, is a key inducer of the biosynthesis of flavonoids. Our study involves the biophysical characterization of MYB12 protein (AtMYB12) under UV-B exposure Tryptophan fluorescence studies using recombinant full-length AtMYB12 (native) and the N-terminal truncated versions (first N-terminal MYB domain absent in AtMYB12Δ1, and both the first and second N-terminal MYB domains absent in AtMYB12Δ2) have revealed prominent alteration in the tryptophan microenvironment in AtMYB12Δ1 and AtMYB12Δ2 protein as a result of UV-B exposure as compared with the native AtMYB12. Bis-ANS binding assay and urea-mediated denaturation profiling showed an appreciable change in the structural conformation in AtMYB12Δ1 and AtMYB12Δ2 proteins as compared with the native AtMYB12 protein following UV-B irradiation. UV-B-treated AtMYB12Δ2 showed a higher predisposition of aggregate formation . CD spectral analyses revealed a decrease in α-helix percentage with a concomitant increase in random coiled structure formation in AtMYB12Δ1 and AtMYB12Δ2 as compared to native AtMYB12 following UV-B treatment. Overall, these findings highlight the critical function of the N-terminal MYB domains in maintaining the stability and structural conformation of the AtMYB12 protein under UV-B stress .
Rao M, Zheng B Antioxidants (Basel). 2025; 14(1).
PMID: 39857408 PMC: 11761259. DOI: 10.3390/antiox14010074.