Riboflavin is the precursor of the redox cofactors flavine mononucleotide and flavine adenindinucleotide. Riboflavin synthase of Escherichia coli has been hyperexpressed to a level of about 30 % of cellular protein. The gene codes for a peptide of 213 amino acids with a molecular mass of 23.4 kDa. Sedimentation equilibrium centrifugation indicated a molecular weight of 70 kDa consistent with a trimer structure.
The aim of the described project is to determine the atomic structure of the enzyme. The protein can be crystallized to a maximal crystal size of 0.5 mm. Crystals of orthorhombic space group symmetry diffracted X-rays to beyond 3 A resolution. The knowledge of the three-dimensional structure of the Escherichia coli enzyme could be helpful in the development of inhibitors of bacterial growth which could be used in antimicrobial therapy. Furthermore, structural modelling of the lumazine synthase / riboflavin synthase complex of Bacillus subtilis will become possible.