Functional expression and characterization of the assimilatory-type sulfite reductase from Desulfovibrio vulgaris (Hildenborough).

By use of a conjugational transfer method, the gene encoding the assimilatory-type sulfite reductase (ASiR) from Desulfovibrio vulgaris (Hildenborough) has been functionally expressed in Desulfovibrio hosts using the broad-host-range plasmid pDSK519. Production is increased greater than 50-fold relative to natural expression levels. Recombinant enzyme has been characterized by standard biochemical methods, nuclear magnetic resonance, electron paramagnetic resonance, electronic absorption, and activity measurements. It cannot be distinguished from the native enzyme on the basis of spectroscopic characteristics or enzyme activity.