Identification, expression, and deduced primary structure of transketolase and other enzymes encoded within the form II CO2 fixation operon of Rhodobacter sphaeroides.
Previous studies had indicated that the form II or B cluster of CO2 fixation structural genes is part of a large operon in Rhodobacter sphaeroides (Gibson, J. L., Chen, J.-H., Tower, P. A., and Tabita, F. R. (1990) Biochemistry 29, 8085-8093). In this investigation, we have sequenced the DNA between the prkB and rbpL genes and provide evidence for three distinct open reading frames which encode additional structural genes of the Calvin reductive pentose phosphate pathway; these genes encode the enzymes transketolase, glyceraldehyde phosphate dehydrogenase, and aldolase. Noteworthy is transketolase, which may be expressed to high levels in Escherichia coli. This study thus represents the initial description of the primary structure of bacterial transketolase, a key enzyme of the reductive and the oxidative pentose phosphate pathways. Each of the genes are separated by short stretches of intergenic sequence, consistent with earlier evidence which suggested that these genes are cotranscribed and part of a large operon controlled by sequences upstream from fbpB.
Department of Microbiology, University of Texas, Austin 78712.
J H
JH
Chen
J L
JL
Gibson
L A
LA
McCue
F R
FR
Tabita
D000595:Amino Acid Sequence; D001483:Base Sequence; D002245:Carbon Dioxide / Q000378:metabolism*; D004269:DNA, Bacterial / Q000235:genetics; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000235:genetics; D015870:Gene Expression; D005798:Genes, Bacterial; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000235:genetics; D008969:Molecular Sequence Data; D005810:Multigene Family; D016366:Open Reading Frames; D009876:Operon; D010957:Plasmids; D015183:Restriction Mapping; D012242:Rhodobacter sphaeroides / Q000235:genetics*; D016415:Sequence Alignment; D012689:Sequence Homology, Nucleic Acid; D014174:Transketolase / Q000235:genetics*
D004269:DNA, Bacterial; D002245:Carbon Dioxide; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; D014174:Transketolase