title: Identity of the subunits and the stoicheiometry of prosthetic groups in trimethylamine dehydrogenase and dimethylamine dehydrogenase.
abstract: Trimethylamine dehydrogenases from bacterium W3A1 and Hyphomicrobium X and the dimethylamine dehydrogenase from Hyphomicrobium X were found to contain only one kind of subunit. The millimolar absorption coefficient of a single [4Fe-4S] cluster in trimethylamine dehydrogenase from bacterium W3A1 was estimated to be 14.8 mM-1 . cm-1 at 443 nm. From this value a 1:1 stoicheiometry of the prosthetic groups, 6-S-cysteinyl-FMN and the [4Fe-4S] cluster, was established. Millimolar absorption coefficients of the three enzymes were in the range 49.4-58.7 mM-1 . cm-1 at approx. 440 nm. This range of values is consistent with the presence of two [4Fe-4S] clusters and two flavin residues, for which the millimolar absorption coefficient had earlier been found to be 12.3 mM-1 . cm-1 at 437 nm. The N-terminal amino acid was alanine in each of the three enzymes. Sequence analysis of the first 15 residues from the N-terminus of dimethylamine dehydrogenase indicated a single unique sequence. Two identical subunits, each containing covalently bound 6-S-cysteinyl-FMN and a [4Fe-4S] cluster, in each of the enzymes are therefore indicated.
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D001419:Bacteria / Q000201:enzymology; D055598:Chemical Phenomena; D002621:Chemistry; D004591:Electrophoresis, Polyacrylamide Gel; D007501:Iron / Q000032:analysis; D046911:Macromolecular Substances; D008970:Molecular Weight; D010089:Oxidoreductases, N-Demethylating; D011487:Protein Conformation; D013455:Sulfur / Q000032:analysis
chemical_list: D000596:Amino Acids; D046911:Macromolecular Substances; D013455:Sulfur; D007501:Iron; D010089:Oxidoreductases, N-Demethylating; C023186:trimethylamine dehydrogenase; C020064:dimethylamine dehydrogenase