Structure-energy relations in methylcobalamin with and without bound axial base

C. Rovira , X. Biarnes , Karel Kunc (1)

1 LOS - Laboratoire d'optique des solides

The properties of the Co-C bond in methylcobalamin (MeCbl) are analyzed by means of first-principles molecular dynamics. The optimized structure is in very good agreement with experiments, reproducing the bent-up deformation of the corrin ring as well as the metal-ligand bond distances. The analysis of the binding energies, bond orders, and vibrational stretching frequencies shows that the axial base slightly weakens the Co-C bond (by 4%), while the alkyl ligand substantially reinforces the Co-axial base bond (by 90%). These findings support several experiments and provide insight into the conversion between the base-on and base-off forms of the MeCbl cofactor.

C. Rovira, X. Biarnes, Karel Kunc. Structure-energy relations in methylcobalamin with and without bound axial base. Inorganic Chemistry, 2004, 43 (21), pp.6628. ⟨10.1021/ic049810s⟩. ⟨hal-00008949⟩