Trimethylamine Dehydrogenase TMADH

Trimethylamine dehydrogenase is an iron-sulfur flavoprotein found in the methylotrophic bacterium Methylophilus methylotrophus W3A1. It catalyzes the oxidative N-demethylation of trimethylamine by water with formation of dimethylamine and formaldehyde (Steenkamp and Mallinson, 1976). The protein is a symmetrical dimer consisting of 166kDa subunits (Kasprzak et al., 1983 Lim et al., 1982). Each subunit contains one 4Fe-4S center and one FMN cofactor. The latter is bound covalently through the 6 

These results are consistent with the behavior of the redox potential of TMADH At pH 7, the two potentials for FMN, E x/sq andE sq/red 

FIGURE 10. Stereo diagram of domain 1 of trimethylamine dehydrogenase. Residues ln371 are shown. Helices aj-ttg of the PgtXg TIM barrel are indicated. The iron sulfur cluster-binding loop consisting of an a-helix and a P-strand is located at the end of helix Og. 

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Like PDR, trimethylamine dehydrogenase (TMADH) from Methylo-philus methylotrophus W3A1 provides an example of a system in which an iron-sulfur center, in this case a [4Fe-4S] cluster, interacts... 

Loechel et al. [20] Trimethylamine Fish Trimethylamine dehydrogenase (TMADH) (Dimethylamine) methylene ferrocene (DMAMFe)... 

The foeus of this chapter is the soluble electron transfer complex formed between the nieotinamide-independent trimethylamine dehydrogenase (TMADH) and eleetron transferring flavoprotein (ETF). Recent studies of this physiological electron transfer complex have provided invaluable insight into (i) the mechanisms of inter and intraprotein electron transfer between flavin and Fe/S centers, (ii) the role of dynamics in interprotein electron transfer and (hi) quantum meehanieal mechanisms for the cleavage of substrate C-H bonds and the subsequent transfer of reducing equivalents to flavin redox centers. Brief mention is made of early structural and cofactor analyses for this redox system, but more detailed accounts of this work can be found in earlier reviews on the subjeet (e.g. Steenkamp and Mathews, 1992). 

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