6q53 | pdb_00006q53

CRYSTAL STRUCTURE OF THE LIGHT-HARVESTING COMPLEX II (B800-850) FROM Ectothiorhodospira haloalkaliphila

spinqualitylabelsall models 6q53, resolution 3.70Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 6q53 is a 4 chain structure. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: BCL, DET, LYC Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [W8L932_9GAMM] Antenna complexes are light-harvesting systems, which transfer the excitation energy to the reaction centers.[SAAS:SAAS00885981] Publication Abstract from PubMed As a basis of photosynthesis, photoinduced oxidation of (bacterio)chlorophyll molecules in the special reaction center complexes has been a subject of extensive research. In contrast, the generally harmful photooxidation of antenna chromoproteins has received much less attention. Here, we have established the permanent structural changes in the LH2 antenna bacteriochlorophyll-protein complex from a sulfur photosynthetic purple bacterium Ectothiorhodospira haloalkaliphila taking place at physiological conditions upon intense optical irradiation. To this end, a crystal structure of the LH2 complex from E. haloalkaliphila was first resolved by X-ray diffraction to 3.7 A, verifying a great similarity with the earlier structure from Phaesporillum molischianum. Analysis of the various steady-state and picosecond time-resolved optical spectroscopy data and related model simulations then confirmed that the major spectral effects observed-bleaching and blue-shifting of the B850 exciton band and correlated emergence of a higher-energy C700 exciton band-are associated with photooxidation of increasing numbers of B850 bacteriochlorophylls into 3-acetyl-chlorophylls, with no noticeable damage to the pigment-binding protein scaffold. A prospective noninvasive method for an in situ optical control of excitons by selective photooxidation of pigment chromophores was thus revealed and demonstrated in a structurally well-defined native system. Controlling Photosynthetic Excitons by Selective Pigment Photooxidation.,Leiger K, Linnanto JM, Ratsep M, Timpmann K, Ashikhmin AA, Moskalenko AA, Fufina TY, Gabdulkhakov AG, Freiberg A J Phys Chem B. 2019 Jan 10;123(1):29-38. doi: 10.1021/acs.jpcb.8b08083. Epub 2018, Dec 27. PMID:30543422 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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