Site Specific Protein Dynamics Probed by Ultrafast Infrared Spectroscopy of a Noncanonical Amino Acid

Hall, Christopher R., Tolentino Collado, Jinnette, Iuliano, James N., Gil, Agnieszka, Adamczyk, Katrin, Lukacs, Andras, Greetham, Gregory M., Sazanovich, Igor, Tonge, Peter J. and Meech, Stephen R. (2019) Site Specific Protein Dynamics Probed by Ultrafast Infrared Spectroscopy of a Noncanonical Amino Acid. Journal of Physical Chemistry B, 123 (45). pp. 9592-9597. ISSN 1520-6106

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Abstract

Real-time observation of structure change associated with protein function remains a major challenge. Ultrafast pump-probe methods record dynamics in light activated proteins, but the assignment of spectroscopic observables to specific structure changes can be difficult. The BLUF (blue light using flavin) domain proteins are an important class of light sensing flavoprotein. Here we incorporate the unnatural amino acid (UAA) azidophenylalanine (AzPhe) at key positions in the H-bonding environment of the isoalloxazine chromophore of two BLUF domains, PixD and AppABLUF; both proteins retain the red shift on irradiation characteristic of photoactivity. Steady state and ultrafast time resolved infrared (TRIR) difference measurements of the azido mode reveal site-specific information on the nature and dynamics of light driven structure change. AzPhe dynamics are thus shown to be an effective probe of BLUF domain photoactivation, revealing significant differences between the two proteins, and a differential response of the two sites to chromophore excitation.

Item Type: Article
Faculty \ School: Faculty of Science > School of Chemistry
Depositing User: LivePure Connector
Date Deposited: 10 Oct 2019 16:30
Last Modified: 22 Apr 2020 08:16
URI: https://ueaeprints.uea.ac.uk/id/eprint/72514
DOI: 10.1021/acs.jpcb.9b09425

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