2bhw
From Proteopedia
PEA LIGHT-HARVESTING COMPLEX II AT 2.5 ANGSTROM RESOLUTION
Overview
The plant light-harvesting complex of photosystem II (LHC-II) collects and transmits solar energy for photosynthesis in chloroplast membranes and has essential roles in regulation of photosynthesis and in photoprotection. The 2.5 A structure of pea LHC-II determined by X-ray crystallography of stacked two-dimensional crystals shows how membranes interact to form chloroplast grana, and reveals the mutual arrangement of 42 chlorophylls a and b, 12 carotenoids and six lipids in the LHC-II trimer. Spectral assignment of individual chlorophylls indicates the flow of energy in the complex and the mechanism of photoprotection in two close chlorophyll a-lutein pairs. We propose a simple mechanism for the xanthophyll-related, slow component of nonphotochemical quenching in LHC-II, by which excess energy is transferred to a zeaxanthin replacing violaxanthin in its binding site, and dissipated as heat. Our structure shows the complex in a quenched state, which may be relevant for the rapid, pH-induced component of nonphotochemical quenching.
About this Structure
2BHW is a Single protein structure of sequence from Pisum sativum. Full crystallographic information is available from OCA.
Reference
Mechanisms of photoprotection and nonphotochemical quenching in pea light-harvesting complex at 2.5 A resolution., Standfuss J, Terwisscha van Scheltinga AC, Lamborghini M, Kuhlbrandt W, EMBO J. 2005 Mar 9;24(5):919-28. Epub 2005 Feb 17. PMID:15719016 Page seeded by OCA on Sat May 3 20:18:44 2008
Categories: Pisum sativum | Single protein | Kuehlbrandt, W. | Lamborghini, M. | Scheltinga, A C.Terwisscha Van. | Standfuss, J. | Chlorophyll | Chloroplast | Chromophore | Lhc-ii | Light-harvesting | Membrane | Membrane protein | Phosphorylation | Photosynthesis | Photosystem i | Photosystem ii | Plastid | Thylakoid | Transit peptide | Transmembrane
