Enoate reductases of Clostridia. Cloning, sequencing, and expression.

The enr genes specifying enoate reductases of Clostridium tyrobutyricum and Clostridium thermoaceticum were cloned and sequenced. Sequence comparison shows that enoate reductases are similar to a family of flavoproteins comprising 2,4-dienoyl-coenzyme A reductase from Escherichia coli and old yellow enzyme from yeast. The C. thermoaceticum enr gene product was expressed in recombinant Escherichia coli cells growing under anaerobic conditions. The recombinant enzyme was purified and characterized.