Figure 1.

Delivery of antibody mimics into the cytosol by the LF_N/PA system. A) Mechanism of entry of antibody mimic (star) into cells. B) Antibody mimics 1–4: affibody (PDB ID: 1Q2N), GB1 (1PGB), DARPin (adapted from 3ZU7), and HA4 (3K2M). C) Variants of antibody mimics (stars) attached to the C terminus of LF_N (Lv) or LF_N-DTA (LDv). D) Protein synthesis inhibition in CHO-K1 cells treated with LDv1–4 in the presence of 20 nm PA for 30 min. The cells were then washed three times with PBS and incubated with 1 μCi ml^{−1 3}H-leucine for 1 h. Subsequently, the cells were washed three times with PBS and scintillation fluid was directly added to each well, and ³H incorporation into the cellular proteome was measured to determine the level of LDv inhibition of protein synthesis (n=3). Radioactive counts were normalized to those of cells treated with only PA (set to 1). •: LF_N-DTA, •: LDv1, ▴: LDv2, ▾: LDv3, ◂: LDv4, ▸: DTA, ⧫: Lv1+DTA.