Scientific article
English

Nanosecond protein dynamics in a red/green cyanobacteriochrome revealed by transient IR spectroscopy

Published inThe Journal of chemical physics, vol. 153, no. 24, 245101
Publication date2020-12-28
First online date2020-12-23
Abstract

Over the last decades, photoreceptive proteins were extensively studied with biophysical methods to gain a fundamental understanding of their working mechanisms and further guide the development of optogenetic tools. Time-resolved infrared (IR) spectroscopy is one of the key methods to access their functional non-equilibrium processes with high temporal resolution but has the major drawback that experimental data are usually highly complex. Linking the spectral response to specific molecular events is a major obstacle. Here, we investigate a cyanobacteriochrome photoreceptor with a combined approach of transient absorption spectroscopy in the visible and IR spectral regions. We obtain kinetic information in both spectral regions by analysis with two different fitting methods: global multiexponential fitting and lifetime analysis. We investigate the ground state dynamics that follow photoexcitation in both directions of the bi-stable photocycle (Pr* and Pg* ) in the nanosecond and microsecond time regimes. We find two ground state intermediates associated with the decay of Pr* and four with Pg* and report the macroscopic time constants of their interconversions. One of these processes is assigned to a structural change in the protein backbone.

Affiliation entities Not a UNIGE publication
Citation (ISO format)
BUHRKE, David et al. Nanosecond protein dynamics in a red/green cyanobacteriochrome revealed by transient IR spectroscopy. In: The Journal of chemical physics, 2020, vol. 153, n° 24, p. 245101. doi: 10.1063/5.0033107
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Identifiers
Journal ISSN0021-9606
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