New England Biolabs: Reagents for the Life Sciences Industry

Strain Properties

There are many properties to consider when choosing a strain for your experiments. Requirements such as plasmid preparation, blue/white screening, cytoplasmic disulfide bond formation, and fast colony growth necessitate specific strain choices. The following selection chart highlights the characteristics of NEB’s strains to help select the optimal strain for a particular experiment.

CAUTION: Chemically Competent E. coli contain DMSO, a hazardous material. Review the MSDS before handling.

ProductNEB #Transform Efficiency (cfu/µg)⁽¹⁾StrainT1 Phage ResistantLibrary Construction⁽²⁾Cloning/Sub CloningBlue/White ScreeninglaclqlysYEndonucleaseI Deficient⁽³⁾Protease Deficient⁽⁴⁾F'RecA¯T7 RNA PolymeraseCytoplasmic disulfide bond formation⁽⁵⁾Drug Resistance⁽⁶⁾
Cloning Strains
NEB® Turbo Competent E. coli (High Efficiency)C2984H
C2984I
1-3x109K12nit
NEB® 5-alpha Competent E. coli (High Efficiency)C2987H
C2987I
C2987P
C2987R
C2987U
1-3x109K12none
NEB® 5-alpha F' Iq Competent E. coli (High Efficiency)C2992H
C2992I
1-3x109K12tetracycline
NEB® 10-beta Competent E. coli (High Efficiency)C3019H
C3019I
1-3x109K12str
dam-/dcm- Competent E. coliC2925H
C2925I
1-3x106K12cam, str and nit
NEB® Stable Competent E. coli (High Efficiency)C3040H
C3040I
1-3 x 109 K12tetracycline and streptomycin
Protein Expression Strains
NEB® Express Competent E. coli (High Efficiency)C2523H
C2523I
0.6-1x109Bnit
NEB® Express Iq Competent E. coli (High Efficiency)C3037I0.6-1x109Bcam and nit
T7 Express Competent E. coli (High Efficiency)C2566H
C2566I
0.6-1x109Bnit
T7 Express lysY Competent E. coli (High Efficiency)C3010I0.6-1x109Bcam and nit
T7 Express lysY/Iq Competent E. coli (High Efficiency)C3013I0.6-1x109Bcam and nit
T7 Express Crystal Competent E. coli (High Efficiency)C3022I0.6-1x109Bnit
SHuffle® T7 Competent E. coliC3026J1 x 106K12str, spec and nit
SHuffle® Express Competent E. coliC3028J1 x 107Bspec, nit and str
SHuffle® T7 Express Competent E. coliC3029J1 x 107Bspec⁽⁷⁾, nit and str
SHuffle® T7 Express lysY Competent E. coliC3030J1 x 107Bcam, spec⁽⁷⁾, nit and str
BL21 Competent E. coliC2530H1-5x107B
BL21(DE3) Competent E. coliC2527H
C2527I
1-5x107B
NiCo21(DE3) Competent E. coliC2529H1-5x107B
Lemo21(DE3) Competent E. coliC2528J1-3x107Bcam
  1. TE given are for high-efficiency chemically competent strains. TE for electrocompetent strains are 1-4 x 1010cfu/mg. TE for subcloning strains are >1 x 106.
  2. Restriction-deficient strain.
  3. Important for plasmid preparation.
  4. Lacks Lon and OmpT protease activity
  5. Constitutively expresses a chromosomal copy of the disulfide bond isomerase DsbC.
  6. nit = nitrofurantoin, tet = tetracycline, cam = chloramphenicol, str = streptomycin, spec = spectinomycin
  7. Resistance to low levels of streptomycin may be observed.