Does distant homology with Evf reveal a lipid binding site in Bacillus thuringiensis cytolytic toxins?
The Cry and Cyt classes of insecticidal toxins derived from the sporulating bacterium Bacillus thuringiensis are valuable substitutes for synthetic pesticides in agricultural contexts. Crystal structures and many biochemical data have provided insights into their molecular mechanisms, generally thought to involve oligomerization and pore formation, but have not localised the site on Cyt toxins responsible for selective binding of phospholipids containing unsaturated fatty acids. Here, distant homology between the structure of Cyt toxins and Erwinia virulence factor (Evf) is demonstrated which, along with sequence conservation analysis, allows a putative lipid binding site to be localised in the toxins.
Rigden
Daniel J
DJ
School of Biological Sciences, University of Liverpool, Crown Street, Liverpool, UK. drigden@liv.ac.uk
D000595:Amino Acid Sequence; D001413:Bacillus thuringiensis / Q000378:metabolism*; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000737:chemistry*; D001665:Binding Sites; D018360:Crystallography, X-Ray; D004731:Endotoxins / Q000737:chemistry*; D004885:Erwinia / Q000472:pathogenicity; D006460:Hemolysin Proteins / Q000737:chemistry*; D008969:Molecular Sequence Data; D011487:Protein Conformation; D017510:Protein Folding; D017386:Sequence Homology, Amino Acid; D037521:Virulence Factors / Q000737:chemistry
D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D004731:Endotoxins; D006460:Hemolysin Proteins; D037521:Virulence Factors; C030956:insecticidal crystal protein, Bacillus Thuringiensis