TY - JOUR
T1 - Transient IR spectroscopy identifies key interactions and unravels new intermediates in the photocycle of a bacterial phytochrome
AU - Kübel, Joachim
AU - Chenchiliyan, Manoop
AU - Ooi, Saik Ann
AU - Gustavsson, Emil
AU - Isaksson, Linnéa
AU - Kuznetsova, Valentyna
AU - Ihalainen, Janne A.
AU - Westenhoff, Sebastian
AU - Maj, Michał
N1 - Publisher Copyright:
© the Owner Societies.
PY - 2020/5/7
Y1 - 2020/5/7
N2 - Phytochromes are photosensory proteins in plants, fungi, and bacteria, which detect red- and far-red light. They undergo a transition between the resting (Pr) and photoactivated (Pfr) states. In bacterial phytochromes, the Pr-to-Pfr transition is facilitated by two intermediate states, called Lumi-R and Meta-R. The molecular structures of the protein in these states are not known and the molecular mechanism of photoconversion is not understood. Here, we apply transient infrared absorption spectroscopy to study the photocycle of the wild-type and Y263F mutant of the phytochrome from Deinococcus radiodurans (DrBphP) from nano- to milliseconds. We identify two sequentially forming Lumi-R states which differ in the local structure surrounding the carbonyl group of the biliverdin D-ring. We also find that the tyrosine at position 263 alters local structure and dynamics around the D-ring and causes an increased rate of Pfr formation. The results shed new light on the mechanism of light-signalling in phytochrome proteins.
AB - Phytochromes are photosensory proteins in plants, fungi, and bacteria, which detect red- and far-red light. They undergo a transition between the resting (Pr) and photoactivated (Pfr) states. In bacterial phytochromes, the Pr-to-Pfr transition is facilitated by two intermediate states, called Lumi-R and Meta-R. The molecular structures of the protein in these states are not known and the molecular mechanism of photoconversion is not understood. Here, we apply transient infrared absorption spectroscopy to study the photocycle of the wild-type and Y263F mutant of the phytochrome from Deinococcus radiodurans (DrBphP) from nano- to milliseconds. We identify two sequentially forming Lumi-R states which differ in the local structure surrounding the carbonyl group of the biliverdin D-ring. We also find that the tyrosine at position 263 alters local structure and dynamics around the D-ring and causes an increased rate of Pfr formation. The results shed new light on the mechanism of light-signalling in phytochrome proteins.
UR - http://www.scopus.com/inward/record.url?scp=85084270899&partnerID=8YFLogxK
U2 - 10.1039/c9cp06995j
DO - 10.1039/c9cp06995j
M3 - Article
C2 - 32149285
AN - SCOPUS:85084270899
SN - 1463-9076
VL - 22
SP - 9195
EP - 9203
JO - Physical Chemistry Chemical Physics
JF - Physical Chemistry Chemical Physics
IS - 17
ER -