The multidimensional Conformational Potential Energy Hypersurface (PEHS) of cyclotrisarcosyl was comprehensively investigated at the DFT (B3LYP/6-31G(d), B3LYP/6-31G(d,p) and B3LYP/6-311++G(d,p)), levels of theory. The equilibrium structures, their relative stability, and the Transition State (TS) structures involved in the conformational interconversion pathways were analyzed. Aug-cc-pVTZ//B3LYP/6-311++G(d,p) and MP2/6-31G(d)//B3LYP/6-311++G(d,p) single point calculations predict a symmetric cis-cis-cis crown conformation as the energetically preferred form for this compound, which is in agreement with the experimental data. The conformational interconversion between the global minimum and the twist form requires 20.88 kcal mol-1 at the MP2/6-31G(d)//B3LYP/6- 311++G(d,p) level of theory. Our results allow us to form a concise idea about the internal intricacies of the PEHSs of this cyclic tripeptide, describing the conformations as well as the conformational interconversion processes in this hypersurface. In addition, a comparative analysis between the conformational behaviors of cyclotrisarcosyl with that previously reported for cyclotriglycine was carried out.Fil: Alvarez, Maria de Los Angeles. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Departamento de Química; ArgentinaFil: Saavedra, Edgardo J.. Universidad Nacional de la Patagonia "San Juan Bosco"; ArgentinaFil: Olivella, Mónica Susana. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Departamento de Química; ArgentinaFil: Suvire, Fernando Daniel. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Departamento de Química; ArgentinaFil: Zamora, Miguel Angel. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Departamento de Química; ArgentinaFil: Enriz, Ricardo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; Argentina. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Departamento de Química; Argentin
