0000000000391888
AUTHOR
Alli Liukkonen
UV-Vis Spectroscopy Reveals a Correlation Between Y263 and BV Protonation States in Bacteriophytochromes
Red‐light photosensory proteins, phytochromes, link light activation to biological functions by interconverting between two conformational states. For this, they undergo large‐scale secondary and tertiary changes which follow small‐scale Z to E bond photoisomerization of the covalently bound bilin chromophore. The complex network of amino acid interactions in the chromophore‐binding pocket plays a central role in this process. Highly conserved Y263 and H290 have been found to be important for the photoconversion yield, while H260 has been identified as important for bilin protonation and proton transfer steps. Here, we focus on the roles these amino acids are playing in preserving the chemi…
UV‐Vis Spectroscopy Reveals a Correlation Between Y263 and BV Protonation States in Bacteriophytochromes
Red-light photosensory proteins, phytochromes, link light activation to biological functions by interconverting between two conformational states. For this, they undergo large-scale secondary and tertiary changes which follow small-scale Z to E bond photoisomerization of the covalently bound bilin chromophore. The complex network of amino acid interactions in the chromophore-binding pocket plays a central role in this process. Highly conserved Y263 and H290 have been found to be important for the photoconversion yield, while H260 has been identified as important for bilin protonation and proton transfer steps. Here, we focus on the roles these amino acids are playing in preserving the chemi…
Site-by-site tracking of signal transduction in an azidophenylalanine-labeled bacteriophytochrome with step-scan FTIR spectroscopy
Signal propagation in photosensory proteins is a complex and multidimensional event. Unraveling such mechanisms site-specifically in real time is an eligible but a challenging goal. Here, we elucidate the site-specific events in a red-light sensing phytochrome using the unnatural amino acid azidophenylalanine, vibrationally distinguishable from all other protein signals. In canonical phytochromes, signal transduction starts with isomerization of an excited bilin chromophore, initiating a multitude of processes in the photosensory unit of the protein, which eventually control the biochemical activity of the output domain, nanometers away from the chromophore. By implementing the label in pri…
Chromophore-Protein Interplay During the Phytochrome Photocycle Revealed by Step-Scan FTIR Spectroscopy
Phytochrome proteins regulate many photoresponses of plants and microorganisms. Light absorption causes isomerization of the biliverdin chromophore, which triggers a series of structural changes to activate the signaling domains of the protein. However, the structural changes are elusive, and therefore the molecular mechanism of signal transduction remains poorly understood. Here, we apply two-color step-scan infrared spectroscopy to the bacteriophytochrome from Deinococcus radiodurans. We show by recordings in H2O and D2O that the hydrogen bonds to the biliverdin D-ring carbonyl become disordered in the first intermediate (Lumi-R) forming a dynamic microenvironment, then completely detach …
CCDC 1524052: Experimental Crystal Structure Determination
UDAKOC : diaqua-(μ-1,13-dioxa-4,7,10,16,19,22-hexaazacyclotetracosane)-bis(perchlorato)-di-copper(ii) diperchlorate tetrahydrate Space Group: P21/c, Cell: a 11.8763(3)Å b 13.9146(4)Å c 13.4024(4)Å, α 90.00° β 123.439(2)° γ 90.00° Work published 2017 via Cambridge Crystallographic Data Centre.