bi0c00382_si_001.pdf (3.76 MB)
Photocycle of Cyanobacteriochrome TePixJ
journal contribution
posted on 2020-08-06, 22:20 authored by Samantha
J. O. Hardman, Derren J. Heyes, Igor V. Sazanovich, Nigel S. ScruttonDue
to the recent advances in X-ray free electron laser techniques,
bilin-containing cyanobacteriochrome photoreceptors have become prime
targets for the ever-expanding field of time-resolved structural biology.
However, to facilitate these challenging studies, it is essential
that the time scales of any structural changes during the photocycles
of cyanobacteriochromes be established. Here, we have used visible
and infrared transient absorption spectroscopy to probe the photocycle
of a model cyanobacteriochrome system, TePixJ. The kinetics span multiple
orders of magnitude from picoseconds to seconds. Localized changes
in the bilin binding pocket occur in picoseconds to nanoseconds, followed
by more large-scale changes in protein structure, including formation
and breakage of a second thioether linkage, in microseconds to milliseconds.
The characterization of the entire photocycle will provide a vital
frame of reference for future time-resolved structural studies of
this model photoreceptor.