Highly Effective Binding of Phosphomonoester with Neutral Cyclic Peptides which- Include a Non-natural Amino Acid

摘要

Receptors for phosphoesters are currently attracting attention due to applications in transportation, catalytic hydrolysis, or complementary transition states. When binding phosphoesters with proteins, the phosphoesters are bound with cationic side chains and/or the backbone of proteins. The general strategy for designing phosphoester receptors is salt formation with cationic groups such as ammonium or pyridiniu. However, there is no report, to our knowledge, about peptide receptors which bind with phosphoesters only via hydrogen bonds to the backbone, namely the amide hydrogen atoms. For this purpose, precise positioning amide groups in a peptide receptor are required. We synthesized cyclic peptides which consist, of alternatmgly natural and non-natural amino acids; 3-aminobenzoic acid (Aba) was used as the latter species to orient the amide group correctly around the phosphoesters. We now report that in the cyclic peptides cyclo(-AA-Aba-)_n (Figure 1; AA denotes an amino acid), a hexapeptide, cyrto(-Ala-Aba-)_3, was found to be a highly efficient receptor for disodium 4-nitropheriyi phosphate despite the neutral peptide.