Abstracts » Biological sciences

The Lactococcus lactis triosephosphate isomerase gene, tpi, is monocistronic

Article Abstract:

Triosephosphate isomerase purified from Lactococcus lactis is a homodimer of noncovalently bound subunits. A lactococcal tpi probe is synthesized using PCR technique from the first 37 amino acid residue sequence from the NH2-terminus. Nucleotide sequencing of the molecular clone of tpi isolated using this probe reveals a 252-amino acid protein with an NH2-terminal sequence identical to the purified enzyme. The triosephosphate isomerase activity of Escherichia coli cells with a tpi-containing plasmid is 15 times higher than that of isogenic plasmid-free cells, confirming the nature of the cloned gene. Northern blot analysis reveals that tpi hybridizes with a 900 base transcript while primer extension analysis reveals the 5' transcription-initiation site to be a G that is 64 bp upstream of the start codon, indicating that tpi is expressed on a monocistronic transcript.

Genetic aspects, Bacteria, Isomerases

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Lactococcus lactis glyceraldehyde-3-phosphate dehydrogenase gene, gap: further evidence for strongly biased codon usage in glycolytic pathway genes

Article Abstract:

The use of Lactococcus lactis bacterium in the making of cheese is prevalent because of the bacterium's ability to produce lactic acid. The process by which lactic acid is made involves the interaction of three metabolic pathways. An analysis of these pathways with the use of molecular probes and cloning and DNA purification revealed the high degree of bias with the codon usage of the glyceraldehyde-3-phosphate dehydrogenase gene.

Research, Cheese, Genetic transcription, Transcription (Genetics), Codon, Codons, Dairy bacteriology, Glycolysis

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