Fig. 2.

Chemical structures of N-aryl peptoid trimer 1 and N-alkyl peptoid trimer 2, shown with their respective solid-state conformations. The crystal structure of peptoid trimer 1 (gray) is represented by both the major conformer (approximately 98% occupancy, iodo group facing down) and the minor conformer (approximately 2% occupancy, iodo group facing up). Superimposed is the REMD prediction (green), which is in close concordance with the major conformer observed by X-ray crystallography (approximately 0.6 Å rmsd-backbone). The crystal structure of trimer 2 exhibits two alternative side chain conformers for residue 2 (69% and 31% occupancies). Superimposed is the lowest-energy conformation predicted by QM (approximately 0.8 Å rmsd-backbone).