Chiral recognition of dipeptides in phosphatidylcholine aggregates

Enantiodiscrimination of ditryptophan enantiomers (l-Trp-l-Trp and d-Trp-d-Trp, l-Trp-d-Trp and d-Trp-l-Trp) was observed in bio-membrane models, such as micellar aggregates of 1,2-diheptanoyl-sn-glycero-3-phospatidylcholine (DHPC) and multilamellar vesicles of either 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) or 1,2-dimyristoyl-sn-glycero-3-phospatidylcholine (DMPC) by solution 1H NMR and HR-MAS 1H NMR, respectively. The attainment of resolved signals, allowed the first detection of enantiodiscrimination at a molecular level, and the identification of the site of chiral recognition and of the interactions and conformations of homo- and heterochiral dipeptides in large-sized aggregates formed by a common component of bio-membranes.