3wa1
Crystal structure of BinB: A receptor binding component of the binary toxin from Lysinibacillus sphaericus
Structural highlights
FunctionBINB2_LYSSH Component of a binary toxin active against Culex and some Aedes mosquito larvae (PubMed:1512580, PubMed:8419297). This subunit is responsible for localized binding to specific regions of the host larval gut. The individual subunits are not toxic. BinAB and this subunit alone bind to the gastric caecum and posterior midgut of C.quinquefasciatus larvae. Binary toxin internalization into host gut cells requires both proteins. Does not bind to the midgut of Aedes aegypti (PubMed:1512580). Toxic to Aedes atropalpus mosquito larvae; mortality towards both C.quinquefasciatus and A.atropalpus is maximal by 48 hours. A.aegypti is not very susceptible to this toxin (PubMed:8419297). Binding component of binary toxin. The 51 kDa polypeptide acts synergetically with the 42 kDa polypeptide for expression of a larvicidal toxin.[1] [2] Publication Abstract from PubMedThe binary toxin (Bin), produced by Lysinibacillus sphaericus, is composed of BinA (42 kDa) and BinB (51 kDa) proteins, which are both required for full toxicity against Culex and Anopheles mosquito larvae. Specificity of Bin toxin is determined by the binding of BinB component to a receptor present on the midgut epithelial membranes, while BinA is proposed to be a toxic component. Here, we determined the first crystal structure of the active form of BinB at a resolution of 1.75 A. BinB possesses two distinct structural domains in its N- and C-termini. The globular N-terminal domain has a beta-trefoil scaffold which is a highly conserved architecture of some sugar binding proteins or lectins, suggesting a role of this domain in receptor-binding. The BinB beta-rich C-terminal domain shares similar three-dimensional folding with aerolysin type beta-pore forming toxins, despite a low sequence identity. The BinB structure, therefore, is a new member of the aerolysin-like toxin family, with probably similarities in the cytolytic mechanism that takes place via pore formation. Proteins 2014; 82:2703-2712. (c) 2014 Wiley Periodicals, Inc. Crystal structure of BinB: A receptor binding component of the binary toxin from Lysinibacillus sphaericus.,Srisucharitpanit K, Yao M, Promdonkoy B, Chimnaronk S, Tanaka I, Boonserm P Proteins. 2014 Oct;82(10):2703-12. doi: 10.1002/prot.24636. Epub 2014 Jul 5. PMID:24975613[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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