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Cloning Competent Cell Strains

Ensure successful transformations with NEB competent E. coli for cloning. Choose from several high efficiency competent cell strains in a variety of formats that deliver performance, convenience and value.

  • High transformation efficiencies
  • Compatible with NEBuilder® HiFi DNA Assembly and Gibson Assembly® reactions, as well as ligation reactions. No dilution required!
  • Strains also available for cloning of toxic genes
  • All strains are free of animal products and are T1 phage resistant
  • Outgrowth medium and control plasmid are included
  • Choose from a variety of convenient formats, including single use tubes
  • Bulk formats and custom packaging are available
  • Take advantage of value pricing and no dry ice charges

Competent Cell Selection Guide

Product NEB # Characteristics Efficiency
NEB® Stable Competent E. coli (High Efficiency) C3040I
  • High quality plasmid preparations due to endA mutation
  • Rapid growth recA strain
  • T1 phage resistance (fhuA)
  • Value pricing
  • Free of animal products
1-3 x 109 cfu/µg
NEB® Turbo Competent E. coli (High Efficiency) C2984I
  • Fastest growth – colonies visible after 6.5 hours
  • Plasmid preparation after 4 hours
  • Tight control/expression of toxic genes (F´lacIq)
1-3 x 109 cfu/µg
NEB® 5-alpha Competent E. coli (High Efficiency) C2987U
  • Versatile cloning strain
  • DH5α™ derivative
1 - 3 x 109 cfu/μg,
For C2987R: 1 - 5 x 108 cfu/μg
NEB® 5-alpha F'Iq Competent E. coli (High Efficiency) C2992I
  • Toxic gene cloning
  • F´ strain with extremely high transformation efficiency
1-3 x 109 cfu/µg
NEB® 10-beta Competent E. coli (High Efficiency) C3019I
  • Large plasmid and BAC cloning
  • DH10B™ derivative
1-3 x 109 cfu/µg
dam-/dcm- Competent E. coli C2925I
  • Dam/Dcm methyltransferase free plasmid growth
1-3 x 106 cfu/µg

Try all four cloning strains in our NEB Competent E. coli Sampler

To help select the best strain for your experiment, please use NEBcloner®, our Cloning Competent Cell Selection Chart or our Strain Properties chart.

Competent Cell Formats

Formats NEB # Single-use 200 µl tubes 96-well plate Electrocompetent Subcloning SOC & Control Plasmid Included
NEB Turbo C2984  
NEB 5-alpha C2987
NEB 5-alpha F'Iq C2992  
NEB 10-beta C3019  
dam-/dcm- C2925  

Choose Type:

FAQs for Cloning Competent Cell Strains

Protocols for Cloning Competent Cell Strains

Advantages of NEB Competent Cells

  • Free of animal products 
  • T1 phage resistance (fhuA2) 
  • Media and control plasmid included with most strains 
  • A variety of convenient formats, including single use transformation tubes and, on request, 96 well plates 
  • Bulk sales capabilities with custom packaging

Advantages of NEB Cloning Strains

  • High transformation efficiencies 
  • EndA deficient for high quality plasmid preparation 
  • T1 phage resistant 
  • RecA deficient for reduced recombination of cloned DNA 
  • Free of animal products 
  • Suitable for blue/white screening 
  • Available as single-use tubes or multiple use aliquots 
  • Outgrowth media and control plasmid included 
  • Bulk sales capabilities with custom packaging formats

High Transformation Efficiencies with NEB Competent E. coli

Transformation efficiencies were compared using manufacturers’ recommended protocols. Values shown are the average of triplicate experiments.

Legal Information

This product is covered by one or more patents, trademarks and/or copyrights owned or controlled by New England Biolabs, Inc (NEB).

While NEB develops and validates its products for various applications, the use of this product may require the buyer to obtain additional third party intellectual property rights for certain applications.

For more information about commercial rights, please contact NEB's Global Business Development team at

This product is intended for research purposes only. This product is not intended to be used for therapeutic or diagnostic purposes in humans or animals.