Structural and biochemical characterization of recombinant wild type and a C30A mutant of trimethylamine dehydrogenase from Methylophilus methylotrophus (sp. W(sub.3)A(sub.1))

Recombinant wild-type and a C30A mutant of trimethylamine dehydrogenase (TMADH) from Methylophilus methylotrophus (sp. W(sub.3)A(sub.1)) have been characterized from the perspectives of structure and biochemistry. Combined crystallographic and NMR studies show inorganic phosphate in the FMN binding site in the deflavo fraction of both recombinant wild-type and C30A proteins. Major differences in kinetic behavior are seen in solution studies. Computational studies show contribution made by the S(gamma) atom of Cys-30 to substrate binding and a role for Cys-30 in the optimal geometrical alignment of substrate with the 6-S-cysteinyl FMN in the enzyme active site.