1oyv
Crystal structure of tomato inhibitor-II in a ternary complex with subtilisin Carlsberg
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| , resolution 2.5Å | |||||||
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| Ligands: | |||||||
| Activity: | Subtilisin, with EC number 3.4.21.62 | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
OverviewOverview
Multidomain proteinase inhibitors play critical roles in the defense of plants against predation by a wide range of pests. Despite a wealth of structural information on proteinase-single domain inhibitor interactions, the structural basis of inhibition by multidomain proteinase inhibitors remains poorly understood. Here we report the 2.5-A resolution crystal structure of the two-headed tomato inhibitor-II (TI-II) in complex with two molecules of subtilisin Carlsberg; it reveals how a multidomain inhibitor from the Potato II family of proteinase inhibitors can bind to and simultaneously inhibit two enzyme molecules within a single ternary complex. The N terminus of TI-II initiates the folding of Domain I (Lys-1 to Cys-15 and Pro-84 to Met-123) and then completes Domain II (Ile-26 to Pro-74) before coming back to complete the rest of Domain I (Pro-84 to Met-123). The two domains of TI-II adopt a similar fold and are arranged in an extended configuration that presents two reactive site loops at the opposite ends of the inhibitor molecule. Each subtilisin molecule interacts with a reactive site loop of TI-II through the standard, canonical binding mode. Remarkably, a significant distortion of the active site of subtilisin is induced by the presence of phenylalanine in the P1 position of reactive site loop II of TI-II. The structure of the TI-II.(subtilisin)2 complex provides a molecular framework for understanding how multiple inhibitory domains in a single Potato II type proteinase inhibitor molecule from the Potato II family act to inhibit proteolytic enzymes.
About this StructureAbout this Structure
1OYV is a Protein complex structure of sequences from Bacillus licheniformis and Solanum lycopersicum. Full crystallographic information is available from OCA.
ReferenceReference
Structural basis of inhibition revealed by a 1:2 complex of the two-headed tomato inhibitor-II and subtilisin Carlsberg., Barrette-Ng IH, Ng KK, Cherney MM, Pearce G, Ryan CA, James MN, J Biol Chem. 2003 Jun 27;278(26):24062-71. Epub 2003 Apr 8. PMID:12684499
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