and catabolic pathways. involved in the regulation of arginine anabolic Dissection of the bifunctional ARGRII protein

by electroelution. Plasmid DNAwas prepared by the alka-line lysis method (4) or rapid-boiling lysis (19).Both single-strand DNAand denaturated double-strandDNA were used as templates for DNA sequencing. Forpreparation of single-strand DNAtemplate, E. coli XL1-Bharboring phagemid pBS(+SK)-ARGRII recombinant plas-mids was grown overnight. Cells were diluted (1:20) intofresh mediumandgrownagainuntil the optical densityat 660nm reached 0.4. Helper phage R408 was added to themixture, and cells were grown for another 6 to 7 h. Single-strand DNAtemplates wereprepared as described byMess-ing (33). For double-strand DNA sequencing, pBR322-ARGRIIrecombinant plasmids were denatured with alkalin(7). DNAsequencing was performed by the dideoxynucle-otide chain termination method of Sanger et al. (40) withhome-made oligomers as primers.Gel retardation assay. (i) Extract preparation. TheargRIIstrain 10R34d-II was transformed with different ARGRIIdeletions inserted into the multicopy plasmidpFL44(pUC19URA3 2 p.m). We used the French pressure cell to makeextracts from 1 liter of culture grown overnight on M.amplus 1 mgofarginine permlto acell concentration of4 x