Abstract
The OspF family of phosphothreonine lyase, including SpvC from Salmonella, irreversibly inactivates the dual-phosphorylated host MAPKs (pT-X-pY) through beta elimination. We determined crystal structures of SpvC and its complex with a phosphopeptide substrate. SpvC adopts a unique fold of alpha/beta type. The disordered N terminus harbors a canonical D motif for MAPK substrate docking. The enzyme-substrate complex structure indicates that recognition of the phosphotyrosine followed by insertion of the threonine phosphate into an arginine pocket places the phosphothreonine into the enzyme active site. This requires the conformational flexibility of pT-X-pY, which suggests that p38 (pT-G-pY) is likely the preferred physiological substrate. Structure-based biochemical and enzymatic analysis allows us to propose a general acid/base mechanism for beta elimination reaction catalyzed by the phosphothreonine lyase. The mechanism described here provides a structural understanding of MAPK inactivation by a family of pathogenic effectors conserved in plant and animal systems and may also open a new route for biological catalysis.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Antigens, Bacterial
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Bacterial Outer Membrane Proteins
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Bacterial Proteins / chemistry*
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Bacterial Proteins / genetics
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Bacterial Proteins / metabolism*
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Binding Sites
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Catalysis
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Cell Line
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Crystallography, X-Ray
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Dual Specificity Phosphatase 6 / chemistry*
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Dual Specificity Phosphatase 6 / genetics
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Dual Specificity Phosphatase 6 / metabolism
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Immunoprecipitation
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Lipoproteins
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Lyases / chemistry*
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Lyases / genetics
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Lyases / metabolism
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Mitogen-Activated Protein Kinase 1 / chemistry*
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Mitogen-Activated Protein Kinase 1 / genetics
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Mitogen-Activated Protein Kinase 1 / metabolism
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Mitogen-Activated Protein Kinase 7 / chemistry*
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Mitogen-Activated Protein Kinase 7 / genetics
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Mitogen-Activated Protein Kinase 7 / metabolism
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Models, Molecular
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Phosphorylation
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Phosphothreonine / metabolism
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Phosphotyrosine / metabolism
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Protein Binding
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Protein Conformation
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Protein Folding
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Salmonella typhimurium / metabolism
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Shigella flexneri / metabolism
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Tyrosine / metabolism
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p38 Mitogen-Activated Protein Kinases / chemistry*
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p38 Mitogen-Activated Protein Kinases / genetics
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p38 Mitogen-Activated Protein Kinases / metabolism
Substances
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Antigens, Bacterial
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Bacterial Outer Membrane Proteins
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Bacterial Proteins
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Lipoproteins
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OspF protein, Borrelia burgdorferi
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Phosphothreonine
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Phosphotyrosine
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Tyrosine
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Mitogen-Activated Protein Kinase 1
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Mitogen-Activated Protein Kinase 7
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p38 Mitogen-Activated Protein Kinases
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Dual Specificity Phosphatase 6
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Lyases