CGSC Strain#: 14177
Strain Designation: BL21(DE3)/pCP20      Source of Strain:
Sex: F- Episome/Plasmid: pCP20
   Plasmid Markers/Mutations: [cI857](λ)(ts), bla(ApR), cat, [FLP], repA101(ts), FLP , Cm , Ap
   Plasmid Comment: pCP20 has the yeast Flp recombinase gene, FLP, chloramphenicol and ampicillin resistant genes, and temperature sensitive replication.
Chromosomal Markers: lon-11, Δ(ompT-nfrA)885, Δ(galM-ybhJ)884, λDE3 [lacI, lacUV5-T7 gene 1, ind1, sam7, nin5], Δ46, [mal⁺]_K-12(λ^S), hsdS10
Strain Comments:

• This strain should be grown on rich media with ampicillin (100 ug/ml at 30 C).
• lon-11-- is a mutation of an E. coli B gene caused by an IS186 insertion in the promoter. All derivatives of Witkin's B wildtype carry this lon mutation.
• Δ(ompT-nfrA)885-- This deletions actually spans from distal region of the DLP12 prophage to an Rhs element just downstream of nfrA in the E. coli B genome. Actual genes deleted are appY, ompT, envY, ybcH, and nfrA.
• Δ(galM-ybhJ)884-- Deletion from base 769,048 to 786,294 in the REL606 genome and includes the following genes: galMKTE, modFE, acrZ, modABC, ybhA, pgl, ybhD, ybhH, ybhI, and ybhJ
• λDE3 [lacI, lacUV5-T7 gene 1, ind1, sam7, nin5]-- Lambda DE3 has the phage T7 RNA polymerase under the control of the lacUV5 promoter inserted into the BamHI site of the Lambda cloning vector D69.
• Δ46-- : cured of defective P2-like prophage found in wildtype E.coli B.
• [mal⁺]_K-12(λ^S)-- The malK, lamB, malM region was transduced in from E. coli K-12.
• Δ(galM-ybhJ)884 was formerly called
• LamS = Lambda sensitive
• ApR = ampicillin resistant
• ts = Temperature Sensitive

References:

• Wood, W.B. 1966. Host specificity of DNA produced by Escherichia coli: bacterial mutations affecting the restriction and modification of DNA. J.Mol.Biol. 16:118-133
• Datsenko, KA, BL Wanner 2000. One-step inactivation of chromosomal genes in Escherichia coli K-12 using PCR products. Proc. Natl. Acad. Sci. U.S.A. 97(12):6640-5.