Phytochrome proteins are light receptors that play a pivotal role in regulating the life cycles of plants and microorganisms. Intriguingly, while cyanobacterial phytochrome Cph1 and cyanobacteriochrome AnPixJ use the same phycocyanobilin (PCB) chromophore to absorb light, their excited-state behavior is very different. We employ multiscale calculations to rationalize the different early photoisomerization mechanisms of PCB in Cph1 and AnPixJ. We found that their electronic S , T , and S potential minima exhibit distinct geometric and electronic structures due to different hydrogen bond networks with the protein environment. These specific interactions influence the S electronic structures along the photoisomerization paths, ultimately leading to internal conversion in Cph1 but intersystem crossing in AnPixJ. This explains why the excited-state relaxation in AnPixJ is much slower (ca. 100 ns) than in Cph1 (ca. 30 ps). Further, we predict that efficient internal conversion in AnPixJ can be achieved upon protonating the carboxylic group that interacts with PCB.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8456922 | PMC |
| http://dx.doi.org/10.1002/anie.202104853 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Spatiotemporal-Dependent Confinement Effect of Bubble Swarms Enables a Fractal Hierarchical Assembly with Promoted Chirality.
J Am Chem Soc
July 2024
Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Green Printing, CAS Research, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China.
The submarine-confined bubble swarm is considered an important constraining environment for the early evolution of living matter due to the abundant gas/water interfaces it provides. Similarly, the spatiotemporal characteristics of the confinement effect in this particular scenario may also impact the origin, transfer, and amplification of chirality in organisms. Here, we explore the confinement effect on the chiral hierarchical assembly of the amphiphiles in the confined bubble array stabilized by the micropillar templates.
View Article and Find Full Text PDFStructural Models of the First Molecular Events in the Heliorhodopsin Photocycle.
J Phys Chem B
June 2024
Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269-3060, United States.
Retinylidene conformations and rearrangements of the hydrogen-bond network in the vicinity of the protonated Schiff base (PSB) play a key role in the proton transfer process in the Heliorhodopsin photocycle. Photoisomerization of the retinylidene chromophore and the formation of photoproducts corresponding to the early intermediates were modeled using a combination of molecular dynamics simulations and quantum mechanical/molecular mechanics calculations. The resulting structures were refined, and the respective excitation energies were calculated.
View Article and Find Full Text PDFConserved tyrosine in phytochromes controls the photodynamics through steric demand and hydrogen bonding capabilities.
Biochim Biophys Acta Bioenerg
November 2023
Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt am Main, Max-von-Laue-Straße 7, 60438 Frankfurt, Germany; Department of Chemistry, University of South Florida, 4202 E. Fowler Avenue, 33620 Tampa, United States of America. Electronic address:
Using ultrafast spectroscopy and site-specific mutagenesis, we demonstrate the central role of a conserved tyrosine within the chromophore binding pocket in the forward (P → P) photoconversion of phytochromes. Taking GAF1 of the knotless phytochrome All2699g1 from Nostoc as representative member of phytochromes, it was found that the mutations have no influence on the early (<30 ps) dynamics associated with conformational changes of the chromophore in the excited state. Conversely, they drastically impact the extended protein-controlled excited state decay (>100 ps).
View Article and Find Full Text PDFSerial Femtosecond Crystallography Reveals that Photoactivation in a Fluorescent Protein Proceeds via the Hula Twist Mechanism.
J Am Chem Soc
July 2023
Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London SW7 2AZ, U.K.
Chromophore photoisomerization is a fundamental process in chemistry and in the activation of many photosensitive proteins. A major task is understanding the effect of the protein environment on the efficiency and direction of this reaction compared to what is observed in the gas and solution phases. In this study, we set out to visualize the hula twist (HT) mechanism in a fluorescent protein, which is hypothesized to be the preferred mechanism in a spatially constrained binding pocket.
View Article and Find Full Text PDFInvestigating the mechanism of photoisomerization in jellyfish rhodopsin with the counterion at an atypical position.
J Biol Chem
June 2023
Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Nagoya, Japan; OptoBioTechnology Research Center, Nagoya Institute of Technology, Nagoya, Japan. Electronic address:
The position of the counterion in animal rhodopsins plays a crucial role in maintaining visible light sensitivity and facilitating the photoisomerization of their retinal chromophore. The counterion displacement is thought to be closely related to the evolution of rhodopsins, with different positions found in invertebrates and vertebrates. Interestingly, box jellyfish rhodopsin (JelRh) acquired the counterion in transmembrane 2 independently.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!