TY  - JOUR
A1  - Fischer, Tobias
A1  - Köhler, Lisa
A1  - Ott, Tanja
A1  - Song, Chen
A1  - Wachtveitl, Josef
A1  - Slavov, Chavdar
T1  - Influence of the PHY domain on the ms-photoconversion dynamics of a knotless phytochrome
T2  - Photochemical & photobiological sciences
N2  - The ability of some knotless phytochromes to photoconvert without the PHY domain allows evaluation of the distinct effect of the PHY domain on their photodynamics. Here, we compare the ms dynamics of the single GAF domain (g1) and the GAF-PHY (g1g2) construct of the knotless phytochrome All2699 from cyanobacterium Nostoc punctiforme. While the spectral signatures and occurrence of the intermediates are mostly unchanged by the domain composition, the presence of the PHY domain slows down the early forward and reverse dynamics involving chromophore and protein binding pocket relaxation. We assign this effect to a more restricted binding pocket imprinted by the PHY domain. The photoproduct formation is also slowed down by the presence of the PHY domain but to a lesser extent than the early dynamics. This indicates a rate limiting step within the GAF and not the PHY domain. We further identify a pH dependence of the biphasic photoproduct formation hinting towards a pKa dependent tuning mechanism. Our findings add to the understanding of the role of the individual domains in the photocycle dynamics and provide a basis for engineering of phytochromes towards biotechnological applications.
KW  - Knotless phytochrome
KW  - Photochemistry
KW  - Time-resolved spectroscopy
KW  - Flash photolysis
Y1  - 2022
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/69471
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-694713
SN  - 1474-9092
N1  - Open Access funding enabled and organized by Projekt DEAL.
VL  - 21
IS  - 9
SP  - 1627
EP  - 1636
PB  - Springer
CY  - Heidelberg
ER  -