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Generate Unmethylated DNA - Details & Specifications

Most E. coli hosts contain both DNA adenine methylation (dam) and DNA cytosine methylation (dcm) genes. These genes code for proteins that methylate specific sequences when DNA is propagated, making subsequent digestion with methylation-sensitive restriction enzymes impossible. Stratagene offers the SCS110 and JM110 strains, which lack both dam and dcm activity. DNA propagated in these strains can be digested by methylation-sensitive enzymes such as Xba I, Cla I and EcoR II.

JM110 Competent Cells

The JM110 strain is useful for preparing plasmid or phagemid DNA that is free of Dam or Dcm methylation so that the DNA can be restriction digested by one or more methylation-sensitive restriction enzymes. JM110 is deficient for two methylases (Dam and Dcm) found in most strains of E. coli. Dam methylase recognizes the DNA sequence GATC and methylates the adenine residue at the N-6 position, while Dcm methylase recognizes the DNA sequence CCAGG and CCTGG and methylates the internal cytosine at the C-5 position. JM110 cells contain the lacIqZΔM15 gene on the F´ episome, allowing blue-white screening for recombinant plasmids.

Efficiency:  5 x 106 transformants/µg of pUC18 DNA

SCS110 Competent Cells

SCS110 is an endA– derivative of the JM110 strain. The SCS110 strain is ideal for preparing plasmid or phagemid DNA free of Dam or Dcm methylation so that the DNA can be restriction digested by one or more methylation sensitive restriction enzymes. SCS110 is deficient for two methylases (Dam and Dcm) found in most strains of E. coli. Dam methylase recognizes the DNA sequence GATC and methylates the adenine residue at the N-6 position, while Dcm methylase recognizes the DNA sequence CCAGG and CCTGG and methylates the internal cytosine at the C-5 position. SCS110 cells are endonuclease (endA) deficient, greatly improving the quality of miniprep DNA. SCS110 cells contain the lacIqZΔM15 gene on the F´ episome, allowing bluewhite screening for recombinant plasmids.

Efficiency:  5 x 106 transformants/µg of pUC18 DNA
Resistant to streptomycin.

For Research Use Only. Not for use in diagnostic procedures