Fig. 2. Structures and functions of remote diphtheria toxin homologs.
a Crystal structure of DT. b Crystal structure of AT solved by SAD-phasing and refined to R and Rfree values of 20.2% and 24.8% (PDB: 7RI3). The four monomers in the ASU align to each other with RMSDs of <1.0 Å. A complete model was built in each of the four chains, except for 4–5 residues from the N-terminus and 0–10 residues from the loop joining the catalytic and translocation domains. Shown is the most complete of the four chains, c crystal structure of Peptono Toxin solved by SAD-phasing and refined to R and Rfree values of 20.2 and 22.5% (PDB: 7RB4). A complete model was built for the monomer in the ASU, apart from the first three N-terminal residues. d Dose titrations of DT, AT, and PT on DT-sensitive Vero cells (mean ± SD, n = 4); n = 3 biological replicates.