1Y7H

Structural and biochemical studies identify tobacco SABP2 as a methylsalicylate esterase and further implicate it in plant innate immunity, Northeast Structural Genomics Target AR2241

Summary for 1Y7H

• Entry DOI: 10.2210/pdb1y7h/pdb
• Related: 1XKL 1Y7I
• Descriptor: salicylic acid-binding protein 2, THIOCYANATE ION (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: 8
• Total formula weight: 247112.47

Authors

Forouhar, F.,Yang, Y.,Kumar, D.,Chen, Y.,Fridman, E.,Park, S.W.,Chiang, Y.,Acton, T.B.,Montelione, G.T.,Pichersky, E.,Klessig, D.F.,Tong, L.,Northeast Structural Genomics Consortium (NESG) (deposition date: 2004-12-08, release date: 2004-12-28, Last modification date: 2024-11-20)

Primary citation

Forouhar, F.,Yang, Y.,Kumar, D.,Chen, Y.,Fridman, E.,Park, S.W.,Chiang, Y.,Acton, T.B.,Montelione, G.T.,Pichersky, E.,Klessig, D.F.,Tong, L.
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

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: 15668381
DOI: 10.1073/pnas.0409227102

Experimental method

X-RAY DIFFRACTION (2.52 Å)