. 2000 Mar 7;97(6):2656–2661. doi: 10.1073/pnas.050578997

Table 3.

Effect of yczA-ycbK operon deletion on trp gene expression in the trpS1 strain

Genetic background	Trp	Anthranilate synthase sp. act. of strain grown at:
Genetic background	Trp	30°C	42°C
trpS⁺ycbK⁺	−	35	28
trpS⁺ycbK⁺	+	12	9
trpS1 ycbK⁺	−	89	NG^*
trpS1 ycbK⁺	+	13	285
trpS1 Δ(leader-yczA-ycbK′)^†	+	10	10
trpS1 Δ(leader-yczA-ycbK′)^† (promoter-yczA-ycbK′ in amyE)^‡	+	9	97

Each assay was performed in duplicate on at least four separate occasions.

NG, No growth at 42°C in the absence of tryptophan.

^† Strain contains a chromosomal deletion of 614 bp of the yczA-ycbK locus and replacement with a spectinomycin-resistance determinant.

^‡ A 736-bp fragment of yczA-ycbK integrated into the amyE locus.