TABLE 2

Effect of the SME-1 gene and its derivatives on E. coli B fitness

Competition experimentSelection rate constant (day−1)
pTP123-SME-1 vs. pTP123−10.7 ± 0.7***
pTP123-SME-1 vs. pTP123-TEM-1−7.0 ± 2.4***
chSME-1 Ara+ vs. chTEM-1 Ara−1.3 ± 0.5***
chSME-1 Ara vs. chTEM-1 Ara+−0.2 ± 0.1**
pTP123-SME-1 vs. Trunc. SME-1−2.2 ± 1.3***
pTP123-SME-1 vs. SMEΔSTART−3.8 ± 2.8***
SMEΔSTART vs. pTP123-TEM-1−0.3 ± 0.7
pTP123-SME-1 vs. SME S70A:E166Q−0.9 ± 1.4
pTP123-SME-1 vs. SME C69V:C238V1.4 ± 1.0*
pTP123-SME-1 vs. TEM(SS)SME−3.9 ± 1.3***
TEM(SS)SME vs. pTP123-TEM-1−0.9 ± 1.2
SME(SS)TEM vs. pTP123-TEM-1−1.4 ± 1.1**
pTP123-SME-1 vs. SME(SS)TEM−4.4 ± 1.2***
  • A negative selection rate constant is indicative of a fitness cost associated with the initial construct (e.g., SME-1) relative to the construct it is competing against (e.g., TEM-1). Significance is based on paired t-test: *0.05 < P < 0.01; **0.01 < P < 0.001; ***P < 0.001.