4a5q
Crystal structure of the chitinase Chi1 fitted into the 3D structure of the Yersinia entomophaga toxin complex
Structural highlights
FunctionCHI1_YERET Part of an orally active toxin complex (TC) with strong insecticidal effects on larvae of the Coleoptera Costelytra zealandica, Acrossidius tasmania and Adoryphorus couloni and some Lepidoptera larvae (PubMed:21278295). The TC has an endochitinase activity (PubMed:21278295, PubMed:22158901) (Probable). This subunit might aid infection by degradation of the larval peritrophic membrane (Probable).[1] [2] [3] Publication Abstract from PubMedYersinia entomophaga MH96 is a native New Zealand soil bacterium that secretes a large ABC-type protein toxin complex, Yen-Tc, similar to those produced by nematode-associated bacteria such as Photorhabdus luminescens. Y. entomophaga displays an exceptionally virulent pathogenic phenotype in sensitive insect species, causing death within 72 h of infection. Because of this phenotype, there is intrinsic interest in the mechanism of action of Yen-Tc, and it also has the potential to function as a novel class of biopesticides. We have identified genes that encode chitinases as part of the toxin complex loci in Y. entomophaga MH96, P. luminescens, Photorhabdus asymbiotica and Xenorhabdus nematophila. Furthermore, we have shown that the secreted toxin complex from Y. entomophaga MH96 includes two chitinases as an integral part of the complex, a feature not described previously in other ABC toxins and possibly related to the severe disease caused by this bacterium. We present here the structure of the Y. entomophaga MH96 Chi1 chitinase, determined by X-ray crystallography to 1.74 A resolution, and show that a ring of five symmetrically arranged lobes on the surface of the Yen-Tc toxin complex structure, as determined by single-particle electron microscopy, provides a good fit to the Chi1 monomer. We also confirm that the isolated chitinases display endochitinase activity, as does the complete toxin complex. Structural Analysis of Chi1 Chitinase from Yen-Tc: The Multisubunit Insecticidal ABC Toxin Complex of Yersinia entomophaga.,Busby JN, Landsberg MJ, Simpson R, Jones SA, Hankamer B, Hurst MR, Lott JS J Mol Biol. 2011 Nov 15. PMID:22108167[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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