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Unfolding of the C-Terminal Jα Helix in the LOV2 Photoreceptor Domain Observed by Time-Resolved Vibrational Spectroscopy
- Source :
- Konold, P E, Mathes, T, Weissenborn, J, Groot, M L, Hegemann, P & Kennis, J T M 2016, ' Unfolding of the C-Terminal Jα Helix in the LOV2 Photoreceptor Domain Observed by Time-Resolved Vibrational Spectroscopy ', Journal of Physical Chemistry Letters, vol. 7, no. 17, pp. 3472-3476 . https://doi.org/10.1021/acs.jpclett.6b01484, Journal of Physical Chemistry Letters, 7(17), 3472-3476. American Chemical Society
- Publication Year :
- 2016
-
Abstract
- Light-triggered reactions of biological photoreceptors have gained immense attention for their role as molecular switches in their native organisms and for optogenetic application. The light, oxygen, and voltage 2 (LOV2) sensing domain of plant phototropin binds a C-terminal Jα helix that is docked on a β-sheet and unfolds upon light absorption by the flavin mononucleotide (FMN) chromophore. In this work, the signal transduction pathway of LOV2 from Avena sativa was investigated using time-resolved infrared spectroscopy from picoseconds to microseconds. In D2O buffer, FMN singlet-to-triplet conversion occurs in 2 ns and formation of the covalent cysteinyl-FMN adduct in 10 μs. We observe a two-step unfolding of the Jα helix: The first phase occurs concomitantly with Cys-FMN covalent adduct formation in 10 μs, along with hydrogen-bond rupture of the FMN C4═O with Gln-513, motion of the β-sheet, and an additional helical element. The second phase occurs in approximately 240 μs. The final spectrum at 500 μs is essentially identical to the steady-state light-minus-dark Fourier transform infrared spectrum, indicating that Jα helix unfolding is complete on that time scale.
- Subjects :
- 0301 basic medicine
Models, Molecular
animal structures
Phototropin
Infrared spectroscopy
Flavin mononucleotide
Photoreceptors, Microbial
Vibration
03 medical and health sciences
chemistry.chemical_compound
General Materials Science
Physical and Theoretical Chemistry
Protein Unfolding
Molecular switch
030102 biochemistry & molecular biology
Chemistry
Hydrogen bond
Arabidopsis Proteins
Spectrum Analysis
food and beverages
Hydrogen Bonding
Chromophore
DNA-Binding Proteins
Crystallography
Microsecond
030104 developmental biology
Helix
Subjects
Details
- ISSN :
- 19487185
- Volume :
- 7
- Issue :
- 17
- Database :
- OpenAIRE
- Journal :
- The journal of physical chemistry letters
- Accession number :
- edsair.doi.dedup.....8e0254702c1dfcae5c95941a5552dd84