Spontaneous Mutations in pcaH,G, Structural Genes for Protocatechuate 3,4-Dioxygenase in Acinetobacter calcoaceticus

摘要

Bacteria containing spontaneous null mutations in pcaH, G, structural genes forprotocatechuate 3,4-dioxygenase, were selected by exposure of an Acinetobacter calcoacedcus strain to physiological conditions in which expression of the genes prevents growth. The parental bacterial strain exhibits high competence for natural taansformation, and this procedure was used to characterize 94 independently isolated spontaneous mutations. Four of the mutations were caused by integration of a newly identified insertion sequence, IS 1236. Many (22/94) of the mutations were lengthy deletions, the largest of which appeared to eliminate