CALVIN CYCLE GENES IN NITROBACTER-VULGARIS-T3

The genes encoding the Calvin cycle enzymes of Nitrobacter vulgaris T3 are found as two separate clusters on the chromosome. One cluster con tains the genes for the large and small subunits fribulose-1,5-bisphos phate carboxylase/oxygenase (RuBisCO), glyceraldehyde-3-phosphate dehy drogenase, and one encoding a regulatory protein of the LysR family. T he other cluster contains the genes for fructose-1,6-/sedoheptulose-1, 7-bisphosphatase, phosphoribulokinase, and fructose-1,6-/sedoheptulose -1,7-bisphosphate aldolase. With the exception of the LysR-like gene, the genes in each cluster are apparently transcribed in the same direc tion. The deduced amino acid sequence of both the large and small subu nits of RuBisCO are most similar (84-86%) to those of Thiobacillus fer rooxidans and Chromatium vinosum. The deduced sequences of phosphoribu lokinase and fructose/sedoheptulose bisphosphatase are 67-73% and 44-4 6% similar to those reported for other autotrophic bacteria, respectiv ely.