Cloning and characterization of the Zymobacter palmae pyruvate decarboxylase gene (pdc) and comparison to bacterial homologues.
Pyruvate decarboxylase (PDC) is the key enzyme in all homo-ethanol fermentations. Although widely distributed among plants, yeasts, and fungi, PDC is absent in animals and rare in bacteria (established for only three organisms). Genes encoding the three known bacterial pdc genes have been previously described and expressed as active recombinant proteins. The pdc gene from Zymomonas mobilis has been used to engineer ethanol-producing biocatalysts for use in industry. In this paper, we describe a new bacterial pdc gene from Zymobacter palmae. The pattern of codon usage for this gene appears quite similar to that for Escherichia coli genes. In E. coli recombinants, the Z. palmae PDC represented approximately 1/3 of the soluble protein. Biochemical and kinetic properties of the Z. palmae enzyme were compared to purified PDCs from three other bacteria. Of the four bacterial PDCs, the Z. palmae enzyme exhibited the highest specific activity (130 U mg of protein(-1)) and the lowest Km for pyruvate (0.24 mM). Differences in biochemical properties, thermal stability, and codon usage may offer unique advantages for the development of new biocatalysts for fuel ethanol production.
Raj
Krishnan Chandra
KC
Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida 32611-0700, USA.
Talarico
Lee A
LA
Ingram
Lonnie O
LO
Maupin-Furlow
Julie A
JA
D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D003062:Codon; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008969:Molecular Sequence Data; D011487:Protein Conformation; D020560:Proteobacteria / Q000201:enzymology* / Q000235:genetics; D011767:Pyruvate Decarboxylase / Q000737:chemistry / Q000235:genetics*; D017386:Sequence Homology, Amino Acid; D013696:Temperature
D003062:Codon; D011767:Pyruvate Decarboxylase