Protein backbone engineering through total chemical synthesis: New insight into the mechanism of HIV-1 protease catalysis

Total chemical synthesis by convergent chemical ligation was used to prepare a 'backbone engineered' 202-residue covalent dimer asymmetric form of the HIV-1 protease molecule. The Gly49-Ile50 peptide bond backbone -N(H)- atom, critically involved in H-bonding to substrates, was specifically replaced by an -O- atom in one flap only. The resulting enzyme analogue retained full intrinsic activity, demonstrating that enzyme-substrate hydrogen bonding at the Gly49-Ile50 peptide bond in only a single flap is sufficient for normal catalytic function. (C) 2000 Elsevier Science Ltd. All rights reserved.