Figure 1
From: An evolved ribosome-inactivating protein targets and kills human melanoma cells in vitro and in vivo
The scRIP SLT-1 A subunit served as a scaffold for the design and construction of an embedded 7-amino acid peptide combinatorial SLT-1 A subunit library. (A) Schematic diagram of the SLT-1 A subunit. Furin cleavage occurs within its protease-sensitive loop (C242 to C261) between residues 251 and 252 (FCS 251/252) of the A subunit [44]. A random 7-amino acid peptide library was inserted between residues 245 and 246, generating cytotoxic A subunit variants with a surface-displayed library insert. Catalytic residues are shown in red. (B) Modeled surface representations of the SLT-1 A subunit with and without a 7-residue long insertion. The models were derived from the crystal structure of Shiga Toxin [45]. The peptide insertion (blue) is solvent-exposed and positioned away from residues involved in catalysis (residues Y77, Y114, E167, R170, W203 colored in red) [20, 46, 47]. Models were rendered using PyMOL Software Version 1.0r1.