Cloning sequencing and over-expression of Escherichia coli malate dehydrogenase

The malate dehydrogenase gene (mdh ) from E. coli W3899 has been cloned and its nucleotide sequence determined. A comparison of the DNA sequence presented here and other E. coli mdh gene sequences reveals a number of important differences including an "apparent" frame shift in the C-terminal region of the gene. The mdh gene was shown to be expressed from its own transcription promotor at a very high level (50% soluble cell protein) in this system and a simple single step procedure for purification of the gene product in large quantities is described.