VS101      Source of Strain:
F- Chromosomal Markers: Δ(gpt-proA)62
, lacZp-topA76(L5F C662H)
, thiE1Strain Comments:
- This strain will grow at 37-42 C in LB + 15 ug/ml chloramphenicol, but for growth at 30 C it requires 1 mM IPTG.
- glnX44(AS)-- Mutation is a C to T transition at nucleotide 34 (3rd position of the anticodon)
- galK2(Oc)-- is a GAA(glu) to TAA(ochre) mutation, residue 134. Oller et al.1993. Apparently non-suppressible, since all revertants found were at the ochre site.
- lacZp-topA76(L5F C662H)-- replaces promoter topAp of allele topA78(G65N W79S substitutions in TopoI) with lacZp, resulting in an IPTG requirement for expression.
- lacZp-topA76(L5F C662H)-- : poor growth at 30C in absence of IPTG; At 42C, TopoI level is low and more negative supercoiling is observed, but the strain grows if it is topB+.
- zci-2234::cat-- is an insertion of cam at a unique SphI site in region 5' (counterclockwise) of the topA gene
- Δ(gpt-proA)62 was formerly called proA2
- galK2(Oc) was formerly called gal2
- glnX44(AS) was formerly called supE44
- glnX44(AS) was formerly called su+II
- glnX44(AS) was formerly called glnV44
- rfbC1 was formerly called rfbD1
- thiE1 was formerly called thi-1
- = chloramphenicol resistant
- AS = amber(UAG) suppressor
- L5F C662H = amino acid changes in TopoI
- Oc = ochre(UAA) mutation
- Stupina, V.A., J.C. Wang 2005. Viability of Escherichia coli topA mutants lacking DNA topoisomerase I. J.Biol.Chem. 280:355-360