1tkw

The transient complex of poplar plastocyanin with turnip cytochrome f determined with paramagnetic NMR

spinqualitylabelsall models 1tkw Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1tkw is a 2 chain structure with sequence from Brassica rapa subsp. rapa and Populus nigra. Full experimental information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Solution NMR, models Ligands: CU, HEC Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function PLAS1_POPNI Participates in electron transfer between P700 and the cytochrome b6-f complex in photosystem I. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed The orientation of poplar plastocyanin in the complex with turnip cytochrome f has been determined by rigid-body calculations using restraints from paramagnetic NMR measurements. The results show that poplar plastocyanin interacts with cytochrome f with the hydrophobic patch of plastocyanin close to the heme region on cytochrome f and via electrostatic interactions between the charged patches on both proteins. Plastocyanin is tilted relative to the orientation reported for spinach plastocyanin, resulting in a longer distance between iron and copper (13.9 A). With increasing ionic strength, from 0.01 to 0.11 M, all observed chemical-shift changes decrease uniformly, supporting the idea that electrostatic forces contribute to complex formation. There is no indication for a rearrangement of the transient complex in this ionic strength range, contrary to what had been proposed earlier on the basis of kinetic data. By decreasing the pH from pH 7.7 to pH 5.5, the complex is destabilized. This may be attributed to the protonation of the conserved acidic patches or the copper ligand His87 in poplar plastocyanin, which are shown to have similar pK(a) values. The results are interpreted in a two-step model for complex formation. The transient complex of poplar plastocyanin with cytochrome f: effects of ionic strength and pH.,Lange C, Cornvik T, Diaz-Moreno I, Ubbink M Biochim Biophys Acta. 2005 Apr-May;1707(2-3):179-88. Epub 2004 Dec 29. PMID:15863096 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Cytochrome f 3D structures Plastocyanin 3D structures

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