Molecular structure of trimethylamine dehydrogenase from the bacterium W3A1 at 6.0-A resolution

An electron density map of trimethylamine dehydrogenase has been calculated at 6.0-A resolution. Protein phases were based on two isomorphous mercury derivatives with similar binding properties, and on anomalous scattering measurements. The map has been averaged about the noncrystallographic 2-fold axis, plotted on transparent sheets and used to construct a wooden model. The elipsoidal dimer has a large inter-subunit interface. Each subunit appears to contain three closely associated domains with the iron-sulfur cluster located between two of them. The map suggests an alpha/beta-structure for two of the domains and a large helix content for the third.