1XKL
Crystal Structure of Salicylic Acid-binding Protein 2 (SABP2) from Nicotiana tabacum, NESG Target AR2241
Summary for 1XKL
| Entry DOI | 10.2210/pdb1xkl/pdb |
| Descriptor | salicylic acid-binding protein 2, 2-AMINO-4H-1,3-BENZOXATHIIN-4-OL (3 entities in total) |
| Functional Keywords | alpha-beta protein, structural genomics, protein structure initiative, psi, northeast structural genomics consortium, nesg, unknown function |
| Biological source | Nicotiana tabacum (common tobacco) |
| Total number of polymer chains | 4 |
| Total formula weight | 125942.92 |
| Authors | Forouhar, F.,Chen, Y.,Chiang, Y.,Acton, T.B.,Montelione, G.T.,Hunt, J.F.,Tong, L.,Northeast Structural Genomics Consortium (NESG) (deposition date: 2004-09-29, release date: 2004-11-30, Last modification date: 2024-10-16) |
| Primary citation | Forouhar, F.,Yang, Y.,Kumar, D.,Chen, Y.,Fridman, E. Structural and biochemical studies identify tobacco SABP2 as a methyl salicylate esterase and implicate it in plant innate immunity Proc.Natl.Acad.Sci.USA, 102:1773-1778, 2005 Cited by PubMed Abstract: Salicylic acid (SA) is a critical signal for the activation of plant defense responses against pathogen infections. We recently identified SA-binding protein 2 (SABP2) from tobacco as a protein that displays high affinity for SA and plays a crucial role in the activation of systemic acquired resistance to plant pathogens. Here we report the crystal structures of SABP2, alone and in complex with SA at up to 2.1-A resolution. The structures confirm that SABP2 is a member of the alpha/beta hydrolase superfamily of enzymes, with Ser-81, His-238, and Asp-210 as the catalytic triad. SA is bound in the active site and is completely shielded from the solvent, consistent with the high affinity of this compound for SABP2. Our biochemical studies reveal that SABP2 has strong esterase activity with methyl salicylate as the substrate, and that SA is a potent product inhibitor of this catalysis. Modeling of SABP2 with MeSA in the active site is consistent with all these biochemical observations. Our results suggest that SABP2 may be required to convert MeSA to SA as part of the signal transduction pathways that activate systemic acquired resistance and perhaps local defense responses as well. PubMed: 15668381DOI: 10.1073/pnas.0409227102 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (2 Å) |
Structure validation
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