Photo-isomerization of the isolated photoactive yellow protein chromophore: what comes before the primary step?. Issue 3 (5th January 2022)

• Record Type: Journal Article
• Authors: Anstöter, Cate S.; Curchod, Basile F. E.; Verlet, Jan R. R.
• Is Part Of: Physical chemistry chemical physics. Volume 24:Issue 3(2021)
• Page Start: 1305
• Page End: 1309
• Publication Date: 2022-01-05
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/d1cp05259d
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : The electronic and nuclear changes that take place before isomerisation sets in for the PYP chromophore anion are captured. Abstract : Photoactive proteins typically rely on structural changes in a small chromophore to initiate a biological response. While these changes often involve isomerization as the "primary step", preceding this is an ultrafast relaxation of the molecular framework caused by the sudden change in electronic structure upon photoexcitation. Here, we capture this motion for an isolated model chromophore of the photoactive yellow protein using time-resolved photoelectron imaging. It occurs in <150 fs and is apparent from a spectral shift of ∼70 meV and a change in photoelectron anisotropy. Electronic structure calculations enable the quantitative assignment of the geometric and electronic structure changes to a planar intermediate from which the primary step can then proceed.