| Structural highlights
Function
YENB_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, PubMed:22158901). The TC has an endochitinase activity (PubMed:21278295) (Probable).[1] [2] [3]
Publication Abstract from PubMed
The ABC toxin complexes produced by certain bacteria are of interest owing to their potent insecticidal activity and potential role in human disease. These complexes comprise at least three proteins (A, B and C), which must assemble to be fully toxic. The carboxy-terminal region of the C protein is the main cytotoxic component, and is poorly conserved between different toxin complexes. A general model of action has been proposed, in which the toxin complex binds to the cell surface via the A protein, is endocytosed, and subsequently forms a pH-triggered channel, allowing the translocation of C into the cytoplasm, where it can cause cytoskeletal disruption in both insect and mammalian cells. Toxin complexes have been visualized using single-particle electron microscopy, but no high-resolution structures of the components are available, and the role of the B protein in the mechanism of toxicity remains unknown. Here we report the three-dimensional structure of the complex formed between the B and C proteins, determined to 2.5 A by X-ray crystallography. These proteins assemble to form an unprecedented, large hollow structure that encapsulates and sequesters the cytotoxic, C-terminal region of the C protein like the shell of an egg. The shell is decorated on one end by a beta-propeller domain, which mediates attachment of the B-C heterodimer to the A protein in the native complex. The structure reveals how C auto-proteolyses when folded in complex with B. The C protein is the first example, to our knowledge, of a structure that contains rearrangement hotspot (RHS) repeats, and illustrates a marked structural architecture that is probably conserved across both this widely distributed bacterial protein family and the related eukaryotic tyrosine-aspartate (YD)-repeat-containing protein family, which includes the teneurins. The structure provides the first clues about the function of these protein repeat families, and suggests a generic mechanism for protein encapsulation and delivery.
The BC component of ABC toxins is an RHS-repeat-containing protein encapsulation device.,Busby JN, Panjikar S, Landsberg MJ, Hurst MR, Lott JS Nature. 2013 Aug 4. doi: 10.1038/nature12465. PMID:23913273[4]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Hurst MR, Jones SA, Binglin T, Harper LA, Jackson TA, Glare TR. The main virulence determinant of Yersinia entomophaga MH96 is a broad-host-range toxin complex active against insects. J Bacteriol. 2011 Apr;193(8):1966-80. doi: 10.1128/JB.01044-10. Epub 2011 Jan 28. PMID:21278295 doi:http://dx.doi.org/10.1128/JB.01044-10
- ↑ Landsberg MJ, Jones SA, Rothnagel R, Busby JN, Marshall SD, Simpson RM, Lott JS, Hankamer B, Hurst MR. 3D structure of the Yersinia entomophaga toxin complex and implications for insecticidal activity. Proc Natl Acad Sci U S A. 2011 Dec 20;108(51):20544-9. doi:, 10.1073/pnas.1111155108. Epub 2011 Dec 7. PMID:22158901 doi:http://dx.doi.org/10.1073/pnas.1111155108
- ↑ Landsberg MJ, Jones SA, Rothnagel R, Busby JN, Marshall SD, Simpson RM, Lott JS, Hankamer B, Hurst MR. 3D structure of the Yersinia entomophaga toxin complex and implications for insecticidal activity. Proc Natl Acad Sci U S A. 2011 Dec 20;108(51):20544-9. doi:, 10.1073/pnas.1111155108. Epub 2011 Dec 7. PMID:22158901 doi:http://dx.doi.org/10.1073/pnas.1111155108
- ↑ Busby JN, Panjikar S, Landsberg MJ, Hurst MR, Lott JS. The BC component of ABC toxins is an RHS-repeat-containing protein encapsulation device. Nature. 2013 Aug 4. doi: 10.1038/nature12465. PMID:23913273 doi:10.1038/nature12465
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