A conformational approach to study the mode of binding of flavin mononucleotide to flavodoxin.

Energetically preferred conformers of Flavin mononucleotide (FMN) were determined using empirical potential energy functions. The minimum energy conformers were used to study the mode of its binding to apoflavodoxin. This study indicates that the conformers of FMN that initiate the binding process undergo significant changes in the position of the phosphate group to reach the final bound conformation. In the bound conformation the phosphate group leads to the formation of a network of hydrogen bonds with the apoflavodoxin and contributes significantly to the binding energy. This extra energy is required for FMN to overcome the repulsion from Met 56 and Glu 59 and to bind tightly to apoflavodoxin.