pH-Switchable strand orientation in peptide assemblies.

[structure: see text] The design of antiparallel coiled-coil heterotrimers with singly mismatched electrostatic interfaces is reported. The new complexes exhibit expected properties for well-formed coiled-coils and have stabilities comparable to those of parallel analogues. The mismatched interface facilitates switching from a parallel to antiparallel complex by pH-triggered strand exchange.