TABLE 3.

Mutational analysis of the shift region in the 3′ terminus of cdd^a

Mutation	DNA sequence and deduced amino acidsb	β-Galactosidase activityc
		In crude extract	% (corrected)d
	K   A   L  LacZ′
	S   E   D   L   H   D   E   R   K   L   *
Wild type	TCG GAG GAT TTA CAT GAC GAA CGA AAG CTT TAA	7,000 ± 250	100 (100)
Stop UAA → Tyr UAC	........................................TAC.	10,800 ± 450	155 (—)e
Leu CUU → Leu CUG	....................................CTG.....	6,000 ± 600	85 (74)
Glu GAA → Glu GAG	........................GAG.................	6,400 ± 200	91 (104)
Lys AAG → Lys AAA	................................AAA.........	410 ± 40	6 (3)
Arg CGA → Arg CGC	............................CGC.............	81 ± 14	1 (2)
Arg CGA → Arg AGA	............................AGA.............	380 ± 40	5 (1)
GGAGG → CGAAG	..C GAA G...................................	640 ± 40	9 (7)
AAG → AAAG	...............................AAAG.........	44,200 ± 1,600	630 (—)

^aAll mutations were introduced into pNMJ62, and the resulting plasmids were transformed into SØ5299. 

^bThe deduced amino acid sequence is shown above the DNA sequence in the 0 (bottom) and −1 (top) reading frames with respect to CDA. The CDA stop codon is in italics, the shift site is underlined, and the SD-like sequence is overlined. Mutations are indicated in bold letters, and the insertion is in bold italics. 

^cEnzyme activities were measured in sonic extracts of cells from exponentially growing cultures. β-Galactosidase activities are expressed in nanomoles per minute per milligram of protein and are the means of nine measurements. 

^dPercentage of the activity measured in the wild type. The numbers in parentheses are corrected for the level of CDA activity in the extracts (β-galactosidase_mutant × CDA_{wild type} × 100/CDA_mutant × β-galactosidase_{wild type}). 

^e—, no detectable CDA activity in extracts.