Femtosecond structural dynamics drives the trans/cis isomerization in photoactive yellow protein

Abstract

A variety of organisms have evolved mechanisms to detect and respond to light, in which the response is mediated by protein structural changes following photon absorption. The initial step is often the photo-isomerization of a conjugated chromophore. Isomerization occurs on ultrafast timescales, and is substantially influenced by the chromophore environment. Here we identify structural changes associated with the earliest steps in the trans to cis isomerization of the chromophore in photoactive yellow protein. Femtosecond, hard X-ray pulses emitted by the Linac Coherent Light Source were used to conduct time-resolved serial femtosecond crystallography on PYP microcrystals over the time range from 100 femtoseconds to 3 picoseconds to determine the structural dynamics of the photoisomerization reaction.

Fluid sample injectors for x-ray free electron laser at SACLA

“…Time-resolved SFX, for example, is becoming a common technique for studying dynamics of proteins [53,54] . In this technique, delivery tools should be compatible with sample activation techniques such as optical pulse irradiation and fast mixing of reactant and sample solutions [33,34] .…”

The next big hit in molecule Hollywood

“…The team's target was photoactive yellow protein (PYP), a light sensor used by some bacteria 3 . At the heart of PYP is a light-absorbing region containing a rigid carbon-carbon double bond that cannot twist freely.…”

Protein–ligand complex structure from serial femtosecond crystallography using soaked thermolysin microcrystals and comparison with structures from synchrotron radiation

“…This 'diffraction-before-destruction' principle of XFELs has successfully been applied in serial femtosecond crystallography (SFX), in which hundreds of thousands of single-shot diffraction images from randomly oriented microcrystals at room temperature are merged to determine a crystal structure (Chapman et al, 2011;Boutet et al, 2012). To date, a substantial number of SFX structures have been reported, including those of natively inhibited trypanosome protease from in vivo-grown microcrystals (Redecke et al, 2013), of membrane proteins from microcrystals grown in lipidic cubic phase (Zhang et al, 2015;Kang et al, 2015) and of the photoactive yellow protein in a time-resolved pump-probe experiment (Pande et al, 2016). Because SFX provides crystal structures at room temperature without radiation damage, it has the potential to be a useful tool in structural biology, which requires structural information under physiological conditions.…”