Expression of the gene for NAD-dependent glucose-6-phosphate dehydrogenase from Leuconostoc mesenteroides cloned in Escherichia coli K-12.

The structural gene (zwf) for Leuconostoc mesenteroides glucose-6-phosphate dehydrogenase has been cloned into Escherichia coli on pBR322 by selecting for complementation of a zwf mutation of E. coli which eliminates glucose-6-phosphate dehydrogenase. The gene has been subcloned on a 3.4-kilobase DNA segment. The encoded glucose-6-phosphate dehydrogenase displays the dual nucleotide specificity (reacting with NAD and NADP) of the L. mesenteroides enzyme and has a subunit Mr of 55,000. A second gene encoding protein of subunit Mr 24,000 is also encoded on the 3.4-kilobase DNA segment. The genes have been located by the analysis of deletions and insertions generated in vitro and by transcriptional mapping with a promoterless chloramphenicol acetyl transferase cartridge inserted at different sites in the 3.4-kilobase fragment.