α-Aminoisobutyric acid: A single amino acid chain inverter

Abstract

Department of Chemistry, Muragachha Government College, University of Kalyani, Nadia-741 235, West Bengal, India E-mail: rajibsarkar.org@gmail.com Manuscript received 16 July 2018, accepted 27 August 2018 A tripeptide, Boc-(L)-Leu(1)-Aib(2)-(L)-Leu(3)-OMe, 1 containing a-aminoisobutyric acid and a coded amino acid was synthe­sized and fully characterized. Then, conformational preference of the tripeptide was studied. The highly hydrophobic peptide adopts bend conformation like a helix. But there is no intramolecular hydrogen bonded regular β or -y turn. The X-ray crystal­lography of the tripeptide shows that the peptide has a helical conformation with consecutive five members N-H.N hydro­gen bonded turn. The single amino acid chain inverter forms a 2→1 N-H.N hydrogen bonds and helical structure which are rare element of proteins.