4jhh | pdb_00004jhh

Crystal Structure of Medicago truncatula Nodulin 13 (MtN13) in complex with kinetin

spinqualitylabelsall models 4jhh, resolution 2.20Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4jhh is a 1 chain structure with sequence from Barrel medic. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: H35, MLI, NA Related: 4jhi, 4gy9, 1icx, 2qim, 3us7, 4jhg Gene: MtN13 (Barrel medic) Resources: FirstGlance, OCA, RCSB, PDBsum Publication Abstract from PubMed Nodulation is an extraordinary symbiotic interaction between leguminous plants and nitrogen-fixing bacteria (rhizobia) that assimilate atmospheric nitrogen (in root nodules) and convert it into compounds suitable for the plant host. A class of plant hormones called cytokinins are involved in the nodulation process. In the model legume Medicago truncatula, nodulin 13 (MtN13), which belongs to the pathogenesis-related proteins of class 10 (PR-10), is expressed in the outer cortex of the nodules. In general, PR-10 proteins are small and monomeric and have a characteristic fold with an internal hydrophobic cavity formed between a seven-stranded antiparallel beta-sheet and a C-terminal alpha-helix. Previously, some PR-10 proteins not related to nodulation were found to bind cytokinins such as trans-zeatin. Here, four crystal structures of the MtN13 protein are reported in complexes with several cytokinins, namely trans-zeatin, N(6)-isopentenyladenine, kinetin and N(6)-benzyladenine. All four phytohormones are bound in the hydrophobic cavity in the same manner and have excellent definition in the electron-density maps. The binding of the cytokinins appears to be strong and specific and is reinforced by several hydrogen bonds. Although the binding stoichiometry is 1:1, the complex is actually dimeric, with a cytokinin molecule bound in each subunit. The ligand-binding site in each cavity is formed with the participation of a loop element from the other subunit, which plugs the only entrance to the cavity. Interestingly, a homodimer of MtN13 is also formed in solution, as confirmed by small-angle X-ray scattering (SAXS). The landscape of cytokinin binding by a plant nodulin.,Ruszkowski M, Szpotkowski K, Sikorski M, Jaskolski M Acta Crystallogr D Biol Crystallogr. 2013 Dec;69(Pt 12):2365-80. doi:, 10.1107/S0907444913021975. Epub 2013 Nov 19. PMID:24311578 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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