3iau

The structure of the processed form of threonine deaminase isoform 2 from Solanum lycopersicum

spinqualitylabelsall models 3iau, resolution 2.35Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3iau is a 2 chain structure with sequence from Lycopersicon esculentum. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: 15P, ACT, SO4 NonStd Res: LLP Gene: TD (Lycopersicon esculentum) Activity: Threonine ammonia-lyase, with EC number 4.3.1.19 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT, TOPSAN 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 Gene duplication is a major source of plant chemical diversity that mediates plant-herbivore interactions. There is little direct evidence, however, that novel chemical traits arising from gene duplication reduce herbivory. Higher plants use threonine deaminase (TD) to catalyze the dehydration of threonine (Thr) to alpha-ketobutyrate and ammonia as the committed step in the biosynthesis of isoleucine (Ile). Cultivated tomato and related Solanum species contain a duplicated TD paralog (TD2) that is coexpressed with a suite of genes involved in herbivore resistance. Analysis of TD2-deficient tomato lines showed that TD2 has a defensive function related to Thr catabolism in the gut of lepidopteran herbivores. During herbivory, the regulatory domain of TD2 is removed by proteolysis to generate a truncated protein (pTD2) that efficiently degrades Thr without being inhibited by Ile. We show that this proteolytic activation step occurs in the gut of lepidopteran but not coleopteran herbivores, and is catalyzed by a chymotrypsin-like protease of insect origin. Analysis of purified recombinant enzymes showed that TD2 is remarkably more resistant to proteolysis and high temperature than the ancestral TD1 isoform. The crystal structure of pTD2 provided evidence that electrostatic interactions constitute a stabilizing feature associated with adaptation of TD2 to the extreme environment of the lepidopteran gut. These findings demonstrate a role for gene duplication in the evolution of a plant defense that targets and co-opts herbivore digestive physiology. Adaptive evolution of threonine deaminase in plant defense against insect herbivores.,Gonzales-Vigil E, Bianchetti CM, Phillips GN Jr, Howe GA Proc Natl Acad Sci U S A. 2011 Apr 5;108(14):5897-902. Epub 2011 Mar 21. PMID:21436043 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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