EFFECT OF CONFORMATIONAL CONSTRAINTS ON THE TOPOGRAPHY OF COMPLEX POTENTIAL-ENERGY SURFACES

The extent to which structural modifications affect the topography of complex molecular energy landscapes is largely unknown. Through quanti tative mapping of the potential energy surfaces of two related hexapep tides, we find that a conformational constraint can completely alter t he character of the molecular energy landscape. The linear peptide exh ibits a single-funnel potential topography, while its cyclic analog ex hibits a shallow energy landscape with competing basins and unevenly d istributed roughness.