Map locations of some mutations conferring resistance to arginine hydroxamate in Bacillus subtilis 168

Mutations conferring resistance to arginine hydroxamate in Bacillus subtilis 168 have been located on the genetic map by PBS1-mediated transduction. The majority of these mutations, belonging to classes 1, 2 and 4 of Harwood and Baumberg (1977) and affecting only expression of arginine catabolic enzymes, map at a locus designated ahr A cotransducible with cysA, purA and sacA. The order of markers in this region appears to be sacA-ahrA-purA-cysA. Certain anomalies were observed in the properties of Pur+ transductants from crosses with an Ahr donor and a purA recipient. A single ahr mutation (class 3), also affecting only arginine catabolism, maps between ctrA and sacA at a locus designated ahrB. Two others (class 6), affecting simultaneously enzymes of both arginine biosynthesis and catabolism, map between lys and aroD at a locus designated ahrC. Preliminary attempts to define the nature of functional products specified by these ahr loci suggest that a protein is encoded at ahrA.