3cn6 | pdb_00003cn6

Crystal structure of the Spinach Aquaporin SoPIP2;1 S274E mutant

spinqualitylabelsall models 3cn6, resolution 2.95Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3cn6 is a 2 chain structure with sequence from Spiol. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: CD Related: 1z98, 2b5f, 3cll, 3cn5 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT 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 Plant plasma membrane aquaporins facilitate water flux into and out of plant cells, thus coupling their cellular function to basic aspects of plant physiology. Posttranslational modifications of conserved phosphorylation sites, changes in cytoplasmic pH and the binding of Ca(2+) can regulate water transport activity by gating the plasma membrane aquaporins. A structural mechanism unifying these diverse biochemical signals has emerged for the spinach aquaporin SoPIP2;1, although several questions concerning the opening mechanism remain. Here, we describe the X-ray structures of the S115E and S274E single SoPIP2;1 mutants and the corresponding double mutant. Phosphorylation of these serines is believed to increase water transport activity of SoPIP2;1 by opening the channel. However, all mutants crystallised in a closed conformation, as confirmed by water transport assays, implying that neither substitution fully mimics the phosphorylated state. Nevertheless, a half-turn extension of transmembrane helix 1 occurs upon the substitution of Ser115, which draws the C(alpha) atom of Glu31 10 A away from its wild-type conformation, thereby disrupting the divalent cation binding site involved in the gating mechanism. Mutation of Ser274 disorders the C-terminus but no other significant conformational changes are observed. Inspection of the hydrogen-bond interactions within loop D suggested that the phosphorylation of Ser188 may also produce an open channel, and this was supported by an increased water transport activity for the S188E mutant and molecular dynamics simulations. These findings add additional insight into the general mechanism of plant aquaporin gating. Structural and functional analysis of SoPIP2;1 mutants adds insight into plant aquaporin gating.,Nyblom M, Frick A, Wang Y, Ekvall M, Hallgren K, Hedfalk K, Neutze R, Tajkhorshid E, Tornroth-Horsefield S J Mol Biol. 2009 Apr 3;387(3):653-68. Epub 2009 Feb 4. PMID:19302796 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Aquaporin 3D structures

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