Nine-residue low-complexity disordered peptide as a model system, an NMR/CD study

Disordered proteins and protein segments can be crucial for biological function. In this work we present a detailed biophysical characterization of the low-complexity nine-residue peptide with the sequence GGKGMGFGL. Based on proton solution NMR chemical shifts, circular dichroism measurements, as well as the analysis of concentration dependence of NMR linewidth, proton longitudinal relaxation times, hydrogen-deuterium exchange measurements, and 15 N rotating frame NMR relaxation measurements, we conclude that the peptide is fully disordered and monomeric in solution. The peptide will serve as a model system for future structural and dynamics studies of biologically relevant disordered peptides in solution and solid states.