3nou

Light-induced intermediate structure L3 of P. aeruginosa bacteriophytochrome

spinqualitylabelsall models 3nou, resolution 3.00Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3nou is a 1 chain structure with sequence from Pseudomonas aeruginosa PAO1. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 3Å Ligands: BLA Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function BPHY_PSEAE Photoreceptor which exists in two forms that are reversibly interconvertible by light: the R form that absorbs maximally in the red region of the spectrum and the FR form that absorbs maximally in the far-red region (By similarity). Publication Abstract from PubMed Light is a fundamental signal that regulates important physiological processes such as development and circadian rhythm in living organisms. Phytochromes form a major family of photoreceptors responsible for red light perception in plants, fungi and bacteria. They undergo reversible photoconversion between red-absorbing (Pr) and far-red-absorbing (Pfr) states, thereby ultimately converting a light signal into a distinct biological signal that mediates subsequent cellular responses. Several structures of microbial phytochromes have been determined in their dark-adapted Pr or Pfr states. However, the structural nature of initial photochemical events has not been characterized by crystallography. Here we report the crystal structures of three intermediates in the photoreaction of Pseudomonas aeruginosa bacteriophytochrome (PaBphP). We used cryotrapping crystallography to capture intermediates, and followed structural changes by scanning the temperature at which the photoreaction proceeded. Light-induced conformational changes in PaBphP originate in ring D of the biliverdin (BV) chromophore, and E-to-Z isomerization about the C(15) = C(16) double bond between rings C and D is the initial photochemical event. As the chromophore relaxes, the twist of the C(15) methine bridge about its two dihedral angles is reversed. Structural changes extend further to rings B and A, and to the surrounding protein regions. These data indicate that absorption of a photon by the Pfr state of PaBphP converts a light signal into a structural signal via twisting and untwisting of the methine bridges in the linear tetrapyrrole within the confined protein cavity. Temperature-scan cryocrystallography reveals reaction intermediates in bacteriophytochrome.,Yang X, Ren Z, Kuk J, Moffat K Nature. 2011 Oct 16;479(7373):428-32. doi: 10.1038/nature10506. PMID:22002602 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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