In Vitro Selection of a Single-Stranded DNA Molecular Recognition Element against Clostridium difficile Toxin B and Sensitive Detection in Human Fecal Matter

Figure 2

Structures of targets used in the SELEX scheme and cross binding assays. (a) Ribbon structure of the selection target, Clostridium difficile toxin B (PDB 2BVM, 270 kDa) [54]. ((b), (c), (d), and (e)) Ribbon structure of Pseudomonas aeruginosa exotoxin A (PDB 1IKQ, 66 kDa) [55], bovine serum albumin (PDB 4F5S, 66.5 kDa) [56], Vibrio cholerae cholera toxin (PDB 2A5D, 84 kDa) [57], and Staphylococcus aureus alpha toxin (PDB 3ANZ, 33 kDa) [58], used in negative rounds of selection and cross binding assays.

(a) Toxin B

(b) Exotoxin A

(c) Bovine serum albumin

(d) Cholera toxin

(e) Alpha toxin