Uniformly nucleobase-functionalized beta-peptide helices: Watson-Crick pairing or nonspecific aggregation

摘要

The organization and architecture of helices is fundamental in folding of protein tertiary structures. Therefore, stable peptide helices are used as models for the selective organization of secondary structures. Nucleobases are already established as recognition elements to organize two beta-peptide helices in antiparallel orientation. The investigation of beta-peptide helices uniformly functionalized with one type of nucleobases provided further insight in the recognition mode and requirements for specific interaction within the linear and very rigid helical backbone topology. Specific helix interaction based on base pair recognition is predominant as soon as Watson-Crick pairing is allowed. If the hydrogen bonding donor/acceptor pattern prohibits the Watson-Crick geometry, a quite stable nonspecific interaction was found based on aromatic interactions or on a nonspecific hydrogen bonding network. The latter aggregation was also confirmed with tyrosine side chains.