An ab initio exploratory study of the full conformational space of MeCO-l-threonine-NH-Me

Ab initio molecular computations were carried out on N- and C-protected l-threonine. Molecular geometry optimizations were conducted on the 81 possible minimum energy conformers of the molecule at the RHF/3-21G level of theory; 39 conformers were located, of which 34 were common with N- and C-protected serine. The relative stabilities of the various conformers have been analyzed in terms of backbone–backbone and backbone–sidechain hydrogen bonding interactions. The stabilization energies exerted by the sidechain of threonine on the backbone are presented as well.