4i38

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

spinqualitylabelsall models 4i38, resolution 1.60Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4i38 is a 1 chain structure with sequence from Halorhodospira halophila. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.6Å Ligands: HC4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function PYP_HALHA Photoactive blue light protein. Probably functions as a photoreceptor for a negative phototaxis response. Publication Abstract from PubMed 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 A. 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. Volume-conserving trans-cis isomerization pathways in photoactive yellow protein visualized by picosecond X-ray crystallography.,Jung YO, Lee JH, Kim J, Schmidt M, Moffat K, Srajer V, Ihee H Nat Chem. 2013 Mar;5(3):212-20. doi: 10.1038/nchem.1565. Epub 2013 Feb 3. PMID:23422563 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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