Identification of a gene required for the oxygen-regulated formation of the photosynthetic apparatus of Rhodobacter capsulatus.
The pigment-binding proteins of Rhodobacter capsulatus are encoded by the polycistronic puf and puc operons. Both operons show higher expression under low oxygen tension than under high oxygen tension in the wild-type strain. The Tn5 mutant strain AH2 shows only low levels of puf and puc mRNA under high and low oxygen tension, indicating that it lacks a gene product required for stimulation of puf and puc gene expression under low oxygen tension. The formation of wild-type levels of photosynthetic complexes and normal oxygen regulation could be restored by the expression in trans of a 1.7 kb fragment of the R. capsulatus wild-type chromosome or by addition of 10 micrograms l-1 vitamin B12 to the growth medium. An open reading frame of 798 nucleotides containing the Tn5 insertion was identified on the 1.7 kb fragment. This open reading frame shows no homology to known genes and has a remarkably high GC content of 76%.
Pollich
M
M
Zentrum für Molekulare Biologie, Heidelberg, Germany.
Jock
S
S
Klug
G
G
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D003001:Cloning, Molecular; D004251:DNA Transposable Elements; D004269:DNA, Bacterial / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D005816:Genetic Complementation Test; D008969:Molecular Sequence Data; D009154:Mutation; D009876:Operon; D010100:Oxygen / Q000378:metabolism*; D010641:Phenotype; D010788:Photosynthesis / Q000235:genetics* / Q000502:physiology; D010860:Pigments, Biological / Q000378:metabolism; D016364:Reading Frames; D015183:Restriction Mapping; D016354:Rhodobacter capsulatus / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism*; D014805:Vitamin B 12 / Q000494:pharmacology
D001426:Bacterial Proteins; D004251:DNA Transposable Elements; D004269:DNA, Bacterial; D010860:Pigments, Biological; D014805:Vitamin B 12; D010100:Oxygen