Guidelines for designing peptoid structures: Insights from the Peptoid Data Bank

The number of structural studies of peptoids has grown dramatically over the past 20 years. To date, over 100 high-resolution structures have been reported for peptoids, which are typically defined as N-substituted glycine oligomers. We have collected these structures and standardized their sequence representations to facilitate structural analysis as the dataset continues to grow. These structures are presented online as The Peptoid Data Bank (), which also provides persistent links to the published structural data. This review analyzes the present collection of structures and finds extensive support for grouping side chains by their chemistry at the position adjacent to the backbone nitrogen. Groups of side chains with similar chemistry at this position show similar influences on the conformational preferences of the backbone. We also observe a relationship between the side chain and backbone conformations for many monomers that has not previously attracted significant discussion: the values of the chi(1) and phi dihedrals are correlated. We outline a general design strategy for attaining a specific backbone conformation based on the patterns seen in the collected structures.