Main content area

An oligomeric complex of BinA/BinB is not formed in-situ in mosquito-larvicidal Lysinibacillus sphaericus ISPC-8

Hire, Ramesh S., Sharma, Mahima, Hadapad, Ashok B., Kumar, Vinay
Journal of invertebrate pathology 2014 v.122 pp. 44-47
Escherichia coli, Lysinibacillus sphaericus, molecular weight, polypeptides, proteomics, recombinant proteins, toxicity
Binary toxin of Lysinibacillus sphaericus is composed of two polypeptides; receptor binding BinB and toxic BinA. Both the polypeptides are required for maximal toxicity. It has been suggested that binary toxin exerts toxicity as a heterotetramer constituted by two copies of each of the component polypeptides. It has also been observed that oligomers consisting of two copies of BinA and BinB are pre-formed in L. sphaericus spore–crystals. However, recombinant proteins from Escherichia coli expression system elute individually as monomers. We purified the likely oligomeric complex from the spore–crystals of highly toxic L. sphaericus ISPC-8 strain and probed it with proteomic tools. The analysis showed that the high molecular mass complex in the toxic spore–crystals is composed of only surface layer protein (SlpC). The purified SlpC from the local isolate exists as a dimer and also showed poor mosquito-larvicidal activity.