We report that in the red light-absorbing (Pr) state, the bilin chromophore of the Deinococcus radiodurans proteobacterial phytochrome (DrBphP) is hypersensitive to X-ray photons used in typical synchrotron X-ray protein crystallography experiments. This causes the otherwise fully protonated chromophore to deprotonate without additional major structural changes. These results have major implications for our understanding of the structural and chemical characteristics of the resting and intermediate states of phytochromes and other photoreceptor proteins.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5660918 | PMC |
| http://dx.doi.org/10.1021/ja510923m | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Single GAF Domain Phytochrome Exhibits a pH-Dependent Shunt on the Millisecond Timescale.
Chemphyschem
January 2025
Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt am Main, Max-von-Laue-Straße 7, 60438, Frankfurt, Germany.
The light-sensing activity of phytochromes is based on the reversible light-induced switching between two isomerization states of the bilin chromophore. These photo-transformations may not necessarily be only unidirectional, but could potentially branch back to the initial ground state in a thermally driven process termed shunt. Such shunts have been rarely reported, and thus our understanding of this process and its governing factors are limited.
View Article and Find Full Text PDFBiliverdin's Propionic Chains Influence Oligomerization in Sandercyanin.
J Phys Chem B
December 2024
Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599, United States.
Sandercyanin is a mildly fluorescent biliprotein with a large Stokes shift, a tetrameric quaternary structure, and a biliverdin (BV) chromophore that does not covalently bond to the protein. To adapt this promising protein for use in bioimaging, it is necessary to produce monomeric mutants that retain the spectroscopic properties while increasing the fluorescence quantum yield. Modulating these properties through the protonation state of BV's propionic tails is a possible avenue, if detailed mechanistic information on the role of such chains becomes available.
View Article and Find Full Text PDFHigh Fluorescence of Phytochromes Does Not Require Chromophore Protonation.
Molecules
October 2024
Institute of Chemistry, Technical University Berlin, Sekr. PC14, Straße des 17. Juni 135, D-10623 Berlin, Germany.
Article Synopsis
- Fluorescing proteins that emit in the near-infrared region, particularly engineered phytochromes, are vital for biomedicine and life sciences, enabling in vivo monitoring of biological systems.
- The study focuses on two minimal phytochromes, miRFP670nano3 and miRFP718nano, examining how their structural characteristics affect the fluorescence of the linked biliverdin chromophore.
- Results indicate that the biliverdin is deprotonated at specific pyrrole rings in both proteins, with differing rates of proton exchange due to their structural dynamics, ultimately influencing their fluorescent efficiency.
Engineering of Phycourobilin Synthase: PubS to a Two-Electron Reductase.
Plant Cell Physiol
September 2024
Department of Biological Sciences, Graduate School of Science, Tokyo Metropolitan University, 1-1 Minami-Ohsawa, Hachioji, Tokyo, 192-0397 Japan.
Phycourobilin:ferredoxin oxidoreductase (PubS) belongs to the ferredoxin-dependent bilin reductase (FDBR) family and catalyzes the reduction of the C15=C16 double bond, followed by the C4=C5 double bond of biliverdin IXα to produce phycourobilin. Among the diverse FDBR enzymes that catalyze site-specific reduction reactions of bilins, PubS lineage is the only one that reduces the C4=C5 double bond. This family can be broadly divided into four-electron reduction enzymes, which catalyze two successive two-electron reductions, such as PubS, and two-electron reduction enzymes, which catalyze a single two-electron reduction.
View Article and Find Full Text PDFProbing bilin-protein interaction in the protochromic photocycle of cyanobacteriochrome RcaE by site-directed mutagenesis.
Plant Cell Physiol
August 2024
Department of Applied Chemistry and Life Science, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku, Toyohashi, Aichi 441-8580, Japan.
Cyanobacteriochromes (CBCRs) are members of the phytochrome superfamily of photosensor proteins that bind a bilin chromophore. CBCRs exhibit substantial diversity in their absorption wavelengths through a variety of bilin-protein interactions. RcaE is the first discovered cyanobacteriochrome as a regulator of chromatic acclimation, where cyanobacteria optimize the absorption wavelength of their photosynthetic antenna.
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!