1pju

Unbound form of Tomato Inhibitor-II

spinqualitylabelsall models 1pju, resolution 2.15Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1pju is a 4 chain structure with sequence from Solanum lycopersicum. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.15Å Ligands: SO4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function IP21_SOLLC Potent inhibitor of both trypsin and chymotrypsin. 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 The Potato II (Pot II) family of proteinase inhibitors plays important roles in the constitutive and inducible defense of plants against predation by a wide range of pests. The structural basis of inhibition by a multidomain Pot II family inhibitor was revealed recently by the structure of the ternary complex between the two-headed tomato inhibitor-II (TI-II) and two molecules of subtilisin Carlsberg. Here we report the 2.15-A resolution crystal structure of the unbound form of TI-II that reveals significant conformational flexibility in the absence of bound proteinase molecules. The four independent copies of unbound TI-II in the asymmetric unit of the unit cell display a range of different conformations when compared with the bound form of the inhibitor, most strikingly in the orientations of the inhibitory domains and in the conformations of the reactive site loops. One of the two linker segments (residues 74 to 79) between the two domains as well as the adjacent beta-strand in Domain I (residues 80-85) is well ordered in all four copies of the unbound inhibitor, even though this region appeared to be disordered in the structure of the ternary complex. Conformational flexibility seen in the reactive site loops of unbound TI-II suggests a mechanism by which the inhibitor can balance the need for tight binding with the need for broad inhibitory function. Unbound form of tomato inhibitor-II reveals interdomain flexibility and conformational variability in the reactive site loops.,Barrette-Ng IH, Ng KK, Cherney MM, Pearce G, Ghani U, Ryan CA, James MN J Biol Chem. 2003 Aug 15;278(33):31391-400. Epub 2003 Jun 4. PMID:12788916 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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