1PJU
Unbound form of Tomato Inhibitor-II
Summary for 1PJU
| Entry DOI | 10.2210/pdb1pju/pdb |
| Related | 1OYV |
| Descriptor | Wound-induced proteinase inhibitor II, SULFATE ION (3 entities in total) |
| Functional Keywords | proteinase inhibitor, hydrolase |
| Biological source | Solanum lycopersicum |
| Cellular location | Secreted: P05119 |
| Total number of polymer chains | 4 |
| Total formula weight | 54641.84 |
| Authors | Barrette-Ng, I.H.,Ng, K.K.-S.,Cherney, M.M.,Pearce, G.,Ghani, U.,Ryan, C.A.,James, M.N.G. (deposition date: 2003-06-03, release date: 2003-09-16, Last modification date: 2024-10-16) |
| Primary citation | Barrette-Ng, I.H.,Ng, K.K.-S.,Cherney, M.M.,Pearce, G.,Ghani, U.,Ryan, C.A.,James, M.N.G. Unbound form of tomato inhibitor-II reveals interdomain flexibility and conformational variability in the reactive site loops J.Biol.Chem., 278:31391-31400, 2003 Cited by PubMed Abstract: 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. PubMed: 12788916DOI: 10.1074/jbc.M304562200 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (2.15 Å) |
Structure validation
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