C.difficile toxin B CROP domain peptides, antibodies and complexes thereof
View Patent ↗The present invention provides polypeptide domains of C. difficile toxin B (B1, B2, B3, B4) and complexes between the polypeptides and antibodies that bind specifically for the polypeptide. Methods of using the polypeptides to generate antibodies are also provided.
1. An isolated crystal comprising a bezlotoxumab Fab fragment complexed to a polypeptide comprising SEQ ID NO: 14, wherein said polypeptide is C. difficile toxin B amino acids 1834-2101 and wherein the crystal is characterized by:
space group: P21; and
unit cell dimensions: a=79.413 Å, b=134.659 Å, c=102.579 Å, α=γ=90°, β=112.559°.
2. The crystal of claim 1 , wherein said polypeptide is characterized by structure coordinates comprising a root mean square deviation (RMSD) of conserved residue backbone atoms of less than about 2.0 angstroms when superimposed on backbone atoms described by structural coordinates of Table 1.
3. A method for producing a crystalline complex of claim 1 comprising incubating a first solution comprising 10 mg/ml of the complex, 5 mM phosphate, pH 7.4, 68.5 mM sodium chloride, 1.35 mM potassium chloride and 2.2% polyethylene glycol 4000 in a sealed container in close proximity to a second solution comprising 4.4 polyethylene glycol 4000.
4. The method of claim 3 wherein the first solution is in the form of a drop which is hanging or sitting on a surface.