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 assim ilatory-type sulfite reductase (ASiR) from Desulfovibrio vulgaris (Hil denborough) has been functionally expressed in Desulfovibrio hosts usi ng the broad-host-range plasmid pDSK519. Production is increased great er than 50-fold relative to natural expression levels. Recombinant enz yme has been characterized by standard biochemical methods, nuclear ma gnetic resonance, electron paramagnetic resonance, electronic absorpti on, and activity measurements. It cannot be distinguished from the nat ive enzyme on the basis of spectroscopic characteristics or enzyme act ivity. (C) 1994 Academic Press, Inc.