Blue-light reception through quaternary transitions
#MMPMID28469162
Engelhard C
; Diensthuber RP
; Möglich A
; Bittl R
Sci Rep
2017[May]; 7
(1
): 1385
PMID28469162
show ga
Sensory photoreceptors absorb light via their photosensor modules and trigger
downstream physiological adaptations via their effector modules. Light reception
accordingly depends on precisely orchestrated interactions between these modules,
the molecular details of which often remain elusive. Using electron-electron
double resonance (ELDOR) spectroscopy and site-directed spin labelling, we chart
the structural transitions facilitating blue-light reception in the engineered
light-oxygen-voltage (LOV) histidine kinase YF1 which represents a paradigm for
numerous natural signal receptors. Structural modelling based on pair-wise
distance constraints derived from ELDOR pinpoint light-induced rotation and
splaying apart of the two LOV photosensors in the dimeric photoreceptor.
Resultant molecular strain likely relaxes as left-handed supercoiling of the
coiled-coil linker connecting sensor and effector units. ELDOR data on a
photoreceptor variant with an inverted signal response indicate a drastically
altered dimer interface but light-induced structural transitions in the linker
that are similar to those in YF1. Taken together, we provide mechanistic insight
into the signal trajectories of LOV photoreceptors and histidine kinases that
inform molecular simulations and the engineering of novel receptors.
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