Fig. 7: Schematic biogenesis pathway of DHFR.
From: Resolving chaperone-assisted protein folding on the ribosome at the peptide level
The N terminus of DHFR emerges from the ribosome in an unstructured state (red) and interacts weakly with L29 at the exit port (1). Synthesis of an additional 27 residues results in the folding of helix α1 and exposes a basic patch that contacts the surface-exposed loop of L23 (2). The remainder of the ABD folds cotranslationally and, while engaged by TF, docks at L23 (3,4). The nascent subdomain is protected from denaturation by occlusion of the succeeding sequence in the exit tunnel. Folding of the DLD, including the N-terminal strand, occurs when the C terminus is provided as a peptide in trans (5) or when the complete domain is released from the exit tunnel upon termination of synthesis (6).
