Table 5.

Combining a deletion of the presumed rut site with a point mutation in the boxA-like region results in near-maximum expression of the tna operon;tnaC translation is required for constitutive expressiona

StraintnaC codon and spacer region ntβ-Gal activity (Miller units)Ratiob
−Trp+Trp
(nt 101–123)
SVS1144 (wild type)AUG1...CGC23CCU24UGAU(UU..CC...CC...C..CCA)...410 ± 3212,890 ± 1,26831
VK1800Δ(nt 101–123)3,450 ± 3124,420 ± 698
VK1800 + bicyclomycin3,120 ± 6303,880 ± 330
VK2000AGC23Δ(nt 101–123)8,970 ± 7669,640 ± 1,027
VK1900UAG1 Δ(nt 101–123)480 ± 57480 ± 72
VK1900 + bicyclomycin2,360 ± 652,320 ± 44
VK2100UAG1...AGC23Δ(nt 101–123)2,365 ± 1542,320 ± 243
VK2100 + bicyclomycin3,075 ± 2003,100 ± 560
  • a Cultures were grown as for Table 2. More than five cultures of each type were assayed in each case. The nucleotide changes introduced are underlined.

  • b Ratio of activities for cultures grown with Trp and without Trp.