1ji6
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(New page: 200px<br /><applet load="1ji6" size="450" color="white" frame="true" align="right" spinBox="true" caption="1ji6, resolution 2.4Å" /> '''CRYSTAL STRUCTURE OF ...)
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Revision as of 16:09, 20 November 2007
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CRYSTAL STRUCTURE OF THE INSECTICIDAL BACTERIAL DEL ENDOTOXIN CRY3Bb1 BACILLUS THURINGIENSIS
Overview
The coleopteran-active delta-endotoxin Cry3Bb1 from Bacillus thuringiensis, (Bt) strain EG7231 is uniquely toxic to Diabrotica undecimpunctata, the, Southern corn rootworm, while retaining activity against Leptinotarsa, decemlineata, the Colorado potato beetle. The crystal structure of the, delta-endotoxin Cry3Bb1 has been refined using data collected to 2.4 A, resolution, with a residual R factor of 17.5% and an R(free) of 25.3%. The, structure is made up of three domains: I, a seven-helix bundle (residues, 64-294); II, a three-sheet domain (residues 295-502); and III, a, beta-sandwich domain (residues 503-652). The monomers in the orthorhombic, C222(1) crystal lattice form a dimeric quaternary structure across a, crystallographic twofold axis, with a channel formed involving, interactions between domains I and III. There are 23 hydrogen bonds, between the two monomers conferring structural stability on the dimer. It, has been demonstrated that Cry3Bb1 and the similar toxin Cry3A form, oligomers in solution. The structural results presented here indicate that, the interactions between domains I and III could be responsible for the, initial higher order structure and have implications for the biological, activity of these toxins. There are seven additional single amino-acid, residues in the sequence of Cry3Bb1 compared with that of Cry3A; one in, domain I, two in domain II and four in domain III, which also shows the, largest conformational difference between the two proteins. These changes, can be implicated in the selectivity differences noted for these two, delta-endotoxins.
About this Structure
1JI6 is a Single protein structure of sequence from Bacillus thuringiensis. Full crystallographic information is available from OCA.
Reference
Structure of the insecticidal bacterial delta-endotoxin Cry3Bb1 of Bacillus thuringiensis., Galitsky N, Cody V, Wojtczak A, Ghosh D, Luft JR, Pangborn W, English L, Acta Crystallogr D Biol Crystallogr. 2001 Aug;57(Pt 8):1101-9. Epub 2001, Jul 23. PMID:11468393
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