Structure and stability of pertussis toxin studied by in situ atomic force microscopy.
Pertussis toxin, both complete and the B-oligomer, were imaged by atomic force microscopy (AFM), using specimens prepared by simple surface adsorption on mica without further manipulation. The spatial arrangement of the subunits of the B-oligomer was clearly resolved, representing the first protein quaternary structure obtained by AFM in situ. The results suggest that the B-oligomer is a flat pentamer with the two large subunits located next to each other, and the catalytic A-subunit situated at the center above. We found that the B-pentamer was structurally stable for temperatures up to 60 degrees C and within the pH range of 4.5-9.5. It is also demonstrated that the AFM was capable of resolving features down to 0.5 nm on the B-oligomers, indicating its great potential for structural determination.
Yang
J
J
Department of Molecular Physiology & Biological Physics, University of Virginia, Charlottesville 22908.
Mou
J
J
Shao
Z
Z
D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D007091:Image Processing, Computer-Assisted; D008853:Microscopy / Q000379:methods; D037342:Pertussis Toxin; D011487:Protein Conformation; D010566:Virulence Factors, Bordetella / Q000737:chemistry*
D010566:Virulence Factors, Bordetella; D037342:Pertussis Toxin