Modulation of Structural Heterogeneity Controls Phytochrome Photoswitching.

Gustavsson E, Isaksson L, Persson C, Mayzel M, Brath U, Vrhovac L, Ihalainen JA, Karlsson BG, Orekhov V, Westenhoff S

Biophysical Journal 118 (2) 415-421 [2020-01-21; online 2019-11-26]

Phytochromes sense red/far-red light and control many biological processes in plants, fungi, and bacteria. Although the crystal structures of dark- and light-adapted states have been determined, the molecular mechanisms underlying photoactivation remain elusive. Here, we demonstrate that the conserved tongue region of the PHY domain of a 57-kDa photosensory module of Deinococcus radiodurans phytochrome changes from a structurally heterogeneous dark state to an ordered, light-activated state. The results were obtained in solution by utilizing a laser-triggered activation approach detected on the atomic level with high-resolution protein NMR spectroscopy. The data suggest that photosignaling of phytochromes relies on careful modulation of structural heterogeneity of the PHY tongue.

Swedish NMR Centre (SNC) [Collaborative]

PubMed 31839260

DOI 10.1016/j.bpj.2019.11.025

Crossref 10.1016/j.bpj.2019.11.025

pii: S0006-3495(19)30948-8
pmc: PMC6976809