Issue 40, 2020

Local dynamics of the photo-switchable protein PYP in ground and signalling state probed by 2D-IR spectroscopy of –SCN labels

Abstract

Incorporation of minimally perturbative vibrational probes into proteins allows combination of the femtosecond time resolution of two dimensional infrared (2D-IR) spectroscopy with a spatial resolution on the level of single side chains. Here, we apply the thiocyanate (–SCN) label introduced by the cyanylation of cysteine to probe local dynamics in the photo-switchable protein PYP. We incorporated the –SCN label into five positions of the protein structure including PYP's core region, its solvent exposed surface and the chromophore-binding pocket. The analysis of –SCN's time dependent 2D-IR lineshape provides insight into the timescales and amplitudes of the dynamics in the label's protein and solvent microenvironment. We present a detailed analysis of the local protein dynamics found at all five labelling positions in PYP's dark state (pG). Absorption of a blue photon triggers the isomerisation of PYP's chromophore and eventually leads to an overall reorganisation of the protein structure, where PYP ends up in a less structured signalling state pB. Employing 2D-IR spectroscopy also on the signalling state allows assessment of the change of local dynamics compared to the pG state.

Graphical abstract: Local dynamics of the photo-switchable protein PYP in ground and signalling state probed by 2D-IR spectroscopy of –SCN labels

Supplementary files

Article information

Article type
Paper
Submitted
23 ذو الحجة 1441
Accepted
12 صفر 1442
First published
12 صفر 1442

Phys. Chem. Chem. Phys., 2020,22, 22963-22972

Local dynamics of the photo-switchable protein PYP in ground and signalling state probed by 2D-IR spectroscopy of –SCN labels

J. M. Schmidt-Engler, L. Blankenburg, R. Zangl, J. Hoffmann, N. Morgner and J. Bredenbeck, Phys. Chem. Chem. Phys., 2020, 22, 22963 DOI: 10.1039/D0CP04307A

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