4I3A

Structures of PR1 and PR2 intermediates from time-resolved laue crystallography collected at 14ID-B, APS

Summary for 4I3A

• Entry DOI: 10.2210/pdb4i3a/pdb
• Related: 1TS0 1TS6 1TS7 1TS8 3VE3 3VE4 4HY8 4I38 4I39 4I3I 4I3J
• Descriptor: Photoactive yellow protein, 4'-HYDROXYCINNAMIC ACID (2 entities in total)
• Functional Keywords: photoreceptor, chromophore, photoreceptor protein, receptor, sensory transduction, luminescent protein
• Biological source: Halorhodospira halophila
• Total number of polymer chains: 1
• Total formula weight: 14052.73

Authors

Jung, Y.O.,Lee, J.H.,Kim, J.,Schmidt, M.,Vukica, S.,Moffat, K.,Ihee, H. (deposition date: 2012-11-26, release date: 2013-03-20, Last modification date: 2025-03-26)

Primary citation

Jung, Y.O.,Lee, J.H.,Kim, J.,Schmidt, M.,Moffat, K.,Srajer, V.,Ihee, H.
Volume-conserving trans-cis isomerization pathways in photoactive yellow protein visualized by picosecond X-ray crystallography
NAT.CHEM., 5:212-220, 2013

PubMed Abstract: Trans-to-cis isomerization, the key reaction in photoactive proteins, usually cannot occur through the standard one-bond-flip mechanism. Owing to spatial constraints imposed by a protein environment, isomerization probably proceeds through a volume-conserving mechanism in which highly choreographed atomic motions are expected, the details of which have not yet been observed directly. Here we employ time-resolved X-ray crystallography to visualize structurally the isomerization of the p-coumaric acid chromophore in photoactive yellow protein with a time resolution of 100 ps and a spatial resolution of 1.6 Å. The structure of the earliest intermediate (I(T)) resembles a highly strained transition state in which the torsion angle is located halfway between the trans- and cis-isomers. The reaction trajectory of I(T) bifurcates into two structurally distinct cis intermediates via hula-twist and bicycle-pedal pathways. The bifurcating reaction pathways can be controlled by weakening the hydrogen bond between the chromophore and an adjacent residue through E46Q mutation, which switches off the bicycle-pedal pathway.

PubMed: 23422563
DOI: 10.1038/nchem.1565

Experimental method

X-RAY DIFFRACTION (1.6 Å)