Journal Article

FZJ-2016-01863

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Photoactivation Reduces Side-Chain Dynamics of a LOV Photoreceptor

Stadler, A. (Corresponding author)FZJ* ; Knieps-Grünhagen, E.FZJ* ; Bocola, M. ; Lohstroh, W. ; Zamponi, M.FZJ* ; Krauss, U.FZJ*

2016
Cell Press Cambridge, Mass.

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Please use a persistent id in citations: doi:10.1016/j.bpj.2016.01.021

Abstract: We used neutron-scattering experiments to probe the conformational dynamics of the light, oxygen, voltage (LOV) photoreceptor PpSB1-LOV from Pseudomonas putida in both the dark and light states. Global protein diffusion and internal macromolecular dynamics were measured using incoherent neutron time-of-flight and backscattering spectroscopy on the picosecond to nanosecond timescales. Global protein diffusion of PpSB1-LOV is not influenced by photoactivation. Observation-time-dependent global diffusion coefficients were found, which converge on the nanosecond timescale toward diffusion coefficients determined by dynamic light scattering. Mean-square displacements of localized internal motions and effective force constants, <k′>, describing the resilience of the proteins were determined on the respective timescales. Photoactivation significantly modifies the flexibility and the resilience of PpSB1-LOV. On the fast, picosecond timescale, small changes in the mean-square displacement and <k′> are observed, which are enhanced on the slower, nanosecond timescale. Photoactivation results in a slightly larger resilience of the photoreceptor on the fast, picosecond timescale, whereas in the nanosecond range, a significantly less resilient structure of the light-state protein is observed. For a residue-resolved interpretation of the experimental neutron-scattering data, we analyzed molecular dynamics simulations of the PpSB1-LOV X-ray structure. Based on these data, it is tempting to speculate that light-induced changes in the protein result in altered side-chain mobility mostly for residues on the protruding Jα helix and on the LOV-LOV dimer interface. Our results provide strong experimental evidence that side-chain dynamics play a crucial role in photoactivation and signaling of PpSB1-LOV via modulation of conformational entropy.

Keyword(s): Health and Life (1st) ; Biology (2nd)

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Contributing Institute(s):

1. Neutronenstreuung (ICS-1)
2. Neutronenstreuung (Neutronenstreuung ; JCNS-1)
3. JCNS-FRM-II (JCNS (München) ; Jülich Centre for Neutron Science JCNS (München) ; JCNS-FRM-II)
4. Institut für Molekulare Enzymtechnologie (HHUD) (IMET)

Research Program(s):

1. 551 - Functional Macromolecules and Complexes (POF3-551) (POF3-551)
2. 6G4 - Jülich Centre for Neutron Research (JCNS) (POF3-623) (POF3-623)
3. 6215 - Soft Matter, Health and Life Sciences (POF3-621) (POF3-621)

Experiment(s):

1. SPHERES: Backscattering spectrometer (NL6S)
2. TOFTOF: Cold neutron time-of-flight spectrometer (NL2au)

Appears in the scientific report 2016

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Database coverage:
; BIOSIS Previews ; Current Contents - Life Sciences ; IF < 5 ; JCR ; NCBI Molecular Biology Database ; No Authors Fulltext ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection

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