title: Photolabeling of Glu-129 of the S-1 subunit of pertussis toxin with NAD.
abstract: UV irradiation was shown to induce efficient transfer of radiolabel from nicotinamide-labeled NAD to a recombinant protein (C180 peptide) containing the catalytic region of the S-1 subunit of pertussis toxin. Incorporation of label from [3H-nicotinamide]NAD was efficient (0.5 to 0.6 mol/mol of protein) relative to incorporation from [32P-adenylate]NAD (0.2 mol/mol of protein). Label from [3H-nicotinamide]NAD was specifically associated with Glu-129. Replacement of Glu-129 with glycine or aspartic acid made the protein refractory to photolabeling with [3H-nicotinamide]NAD, whereas replacement of a nearby glutamic acid, Glu-139, with serine did not. Photolabeling of the C180 peptide with NAD is similar to that observed with diphtheria toxin and exotoxin A of Pseudomonas aeruginosa, in which the nicotinamide portion of NAD is transferred to Glu-148 and Glu-553, respectively, in the two toxins. These results implicate Glu-129 of the S-1 subunit as an active-site residue and a potentially important site for genetic modification of pertussis toxin for development of an acellular vaccine against Bordetella pertussis.
authors: Department of Microbiology, Medical College of Wisconsin, Milwaukee 53226.
authors: J T
authors: JT
authors: Barbieri
authors: L M
authors: LM
authors: Mende-Mueller
authors: R
authors: R
authors: Rappuoli
authors: R J
authors: RJ
authors: Collier
mesh_terms: D003488:Cyanogen Bromide; D005971:Glutamates; D009243:NAD; D010446:Peptide Fragments; D037342:Pertussis Toxin; D010777:Photochemistry; D011994:Recombinant Proteins; D014357:Trypsin; D014466:Ultraviolet Rays; D010566:Virulence Factors, Bordetella
chemical_list: D005971:Glutamates; D010446:Peptide Fragments; D011994:Recombinant Proteins; D010566:Virulence Factors, Bordetella; D009243:NAD; D037342:Pertussis Toxin; D014357:Trypsin; D003488:Cyanogen Bromide