CLONING, NUCLEOTIDE-SEQUENCE, AND TRANSCRIPTIONAL ANALYSIS OF THE PEDIOCOCCUS-ACIDILACTICI L-(-LACTATE DEHYDROGENASE GENE())

Recombinant plasmids containing the Pediococcus acidilactici L-(+)-lac tate dehydrogenase gene (ldhL) were isolated by complementing for grow th under anaerobiosis of an Escherichia coli lactate dehydrogenase-pyr uvate formate lyase double mutant. The nucleotide sequence of the ldhL gene predicted a protein of 323 amino acids showing significant simil arity with other bacterial L-(+)-lactate dehydrogenases and especially with that of Lactobacillus plantarum. The ldhL transcription start po ints in P. acidilactici were defined by primer extension, and the prom oter sequence was identified as TCAACT-(17 bp)-TATAAT. This sequence i s closely related to the consensus sequence of vegetative promoters fr om gram-positive bacteria as well as from E. coli. Northern analysis o f P. acidilactici RNA showed a 1.1-kb ldhL transcript whose abundance is growth rate regulated. These data, together with the presence of a putative rho-independent transcriptional terminator, suggest that ldhL is expressed as a monocistronic transcript in P. acidilactici.