title: An oligomeric complex of BinA/BinB is not formed in-situ in mosquito-larvicidal Lysinibacillus sphaericus ISPC-8.
abstract: 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.
authors.affiliation: Nuclear Agriculture & Biotechnology Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India.
authors.forename: Ramesh S
authors.initials: RS
authors.lastname: Hire
authors.affiliation: Solid State Physics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India.
authors.forename: Mahima
authors.initials: M
authors.lastname: Sharma
authors.affiliation: Nuclear Agriculture & Biotechnology Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India.
authors.forename: Ashok B
authors.initials: AB
authors.lastname: Hadapad
authors.affiliation: Solid State Physics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India. Electronic address: vinay@barc.gov.in.
authors.forename: Vinay
authors.initials: V
authors.lastname: Kumar
mesh_terms: D000818:Animals; D001407:Bacillus / Q000737:chemistry*; D001427:Bacterial Toxins / Q000737:chemistry* / Q000378:metabolism / Q000633:toxicity*; D003465:Culex / Q000382:microbiology*; D040901:Proteomics; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D001427:Bacterial Toxins
keywords: Binary protein; Culex quinquefasciatus; Lysinibacillus sphaericus; Surface layer protein