Adaptation to Low CO(2) Level in a Mutant of Anacystis nidulans R(2) which Requires High CO(2) for Growth.

The mutant E(1) of Anacystis nidulans R(2) requires high CO(2) concentration for growth but was able to adapt to low CO(2) concentration. This was exhibited by the increased ability to accumulate inorganic carbon within the cells and the large increase in the amount of a 42-kilodalton polypeptide located in the cytoplasmic membrane. The adaptation occurred in E(1) cells at an extracellular CO(2) concentration as high as 0.3%, which was 8 times the concentration for maximal adaptation in R(2) cells. The ability of E(1) cells to exhibit low CO(2) characteristics at a higher CO(2) concentration was attributed to lower intracellular CO(2) concentration.