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	<id>https://eln.excellgen.com/index.php?action=history&amp;feed=atom&amp;title=Invitrogen_Competent_Cells</id>
	<title>Invitrogen Competent Cells - Revision history</title>
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	<updated>2026-10-18T06:27:08Z</updated>
	<subtitle>Revision history for this page on the wiki</subtitle>
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	<entry>
		<id>https://eln.excellgen.com/index.php?title=Invitrogen_Competent_Cells&amp;diff=3704&amp;oldid=prev</id>
		<title>Paul.xu: Created page with &quot;{| width=&quot;100%&quot; cellspacing=&quot;0&quot; |- ! valign=&quot;top&quot; | Product Name  ! valign=&quot;top&quot; | Genotype |- | valign=&quot;top&quot; |  BL21-AI™  | valign=&quot;top&quot; |  F– ompT hsdSB(rB–, mB–) gal d...&quot;</title>
		<link rel="alternate" type="text/html" href="https://eln.excellgen.com/index.php?title=Invitrogen_Competent_Cells&amp;diff=3704&amp;oldid=prev"/>
		<updated>2012-04-01T02:37:09Z</updated>

		<summary type="html">&lt;p&gt;Created page with &amp;quot;{| width=&amp;quot;100%&amp;quot; cellspacing=&amp;quot;0&amp;quot; |- ! valign=&amp;quot;top&amp;quot; | Product Name  ! valign=&amp;quot;top&amp;quot; | Genotype |- | valign=&amp;quot;top&amp;quot; |  BL21-AI™  | valign=&amp;quot;top&amp;quot; |  F– ompT hsdSB(rB–, mB–) gal d...&amp;quot;&lt;/p&gt;
&lt;p&gt;&lt;b&gt;New page&lt;/b&gt;&lt;/p&gt;&lt;div&gt;{| width=&amp;quot;100%&amp;quot; cellspacing=&amp;quot;0&amp;quot;&lt;br /&gt;
|-&lt;br /&gt;
! valign=&amp;quot;top&amp;quot; | Product Name &lt;br /&gt;
! valign=&amp;quot;top&amp;quot; | Genotype&lt;br /&gt;
|-&lt;br /&gt;
| valign=&amp;quot;top&amp;quot; | &lt;br /&gt;
BL21-AI™&lt;br /&gt;
&lt;br /&gt;
| valign=&amp;quot;top&amp;quot; | &lt;br /&gt;
F– ompT hsdSB(rB–, mB–) gal dcm araB::T7RNAP-tetA &lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| valign=&amp;quot;top&amp;quot; | &lt;br /&gt;
BL21(DE3)&lt;br /&gt;
&lt;br /&gt;
| valign=&amp;quot;top&amp;quot; | &lt;br /&gt;
F– ompT hsdSB(rB–, mB–) gal dcm (DE3) &lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| valign=&amp;quot;top&amp;quot; | &lt;br /&gt;
BL21(DE3)pLysS &lt;br /&gt;
&lt;br /&gt;
| valign=&amp;quot;top&amp;quot; | &lt;br /&gt;
F– ompT hsdSB(rB–, mB–) gal dcm (DE3) pLysS (CamR) &lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| valign=&amp;quot;top&amp;quot; | &lt;br /&gt;
BL21(DE3)pLysE&amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
| valign=&amp;quot;top&amp;quot; | &lt;br /&gt;
F– ompT hsdSB(rB–, mB–) gal dcm (DE3) pLysE (CamR)&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| valign=&amp;quot;top&amp;quot; | &lt;br /&gt;
BL21 Star™(DE3)&amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
| valign=&amp;quot;top&amp;quot; | &lt;br /&gt;
F– ompT hsdSB(rB–, mB–) gal dcm rne131 (DE3)&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| valign=&amp;quot;top&amp;quot; | &lt;br /&gt;
BL21 Star™ (DE3)pLysS&lt;br /&gt;
&lt;br /&gt;
| valign=&amp;quot;top&amp;quot; | &lt;br /&gt;
F– ompT hsdSB(rB–, mB–) gal dcm rne131 (DE3) pLysS (CamR) &lt;br /&gt;
&lt;br /&gt;
|}&lt;br /&gt;
&amp;lt;div&amp;gt;&amp;lt;/div&amp;gt;&amp;lt;div&amp;gt;&amp;lt;br&amp;gt;&lt;br /&gt;
{| cellspacing=&amp;quot;0&amp;quot; cellpadding=&amp;quot;0&amp;quot; border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-&lt;br /&gt;
! Sku &lt;br /&gt;
! Product Catalog &lt;br /&gt;
! Size &lt;br /&gt;
! Price&lt;br /&gt;
|-&lt;br /&gt;
| A11154 &lt;br /&gt;
| PichiaPink™ Expression Strain Set &lt;br /&gt;
| 4 × 1ml&amp;lt;br&amp;gt; &lt;br /&gt;
| id=&amp;quot;price1&amp;quot; | 1,067.31 USD&amp;lt;br&amp;gt;&lt;br /&gt;
|-&lt;br /&gt;
| C6000-03 &lt;br /&gt;
| One Shot® BL21(DE3) Chemically Competent E. coli &lt;br /&gt;
| 20 × 50 µl&amp;lt;br&amp;gt; &lt;br /&gt;
| id=&amp;quot;price2&amp;quot; | 253.26 USD&amp;lt;br&amp;gt;&lt;br /&gt;
|-&lt;br /&gt;
| C6010-03 &lt;br /&gt;
| One Shot® BL21 Star™ (DE3) Chemically Competent E. coli &lt;br /&gt;
| 20 reactions&amp;lt;br&amp;gt; &lt;br /&gt;
| id=&amp;quot;price3&amp;quot; | 331.65 USD&amp;lt;br&amp;gt;&lt;br /&gt;
|-&lt;br /&gt;
| C6020-03 &lt;br /&gt;
| BL21 Star™ (DE3)pLysS One Shot® Chemically Competent E. &lt;br /&gt;
coli &lt;br /&gt;
&lt;br /&gt;
| 20 × 50 µl&amp;lt;br&amp;gt; &lt;br /&gt;
| id=&amp;quot;price4&amp;quot; | 334.67 USD&amp;lt;br&amp;gt;&lt;br /&gt;
|-&lt;br /&gt;
| C6060-03 &lt;br /&gt;
| One Shot® BL21(DE3)pLysS Chemically Competent E. coli &lt;br /&gt;
| 20 × 50 µl&amp;lt;br&amp;gt; &lt;br /&gt;
| id=&amp;quot;price5&amp;quot; | 281.40 USD&amp;lt;br&amp;gt;&lt;br /&gt;
|-&lt;br /&gt;
| C6060-10 &lt;br /&gt;
| One Shot® BL21(DE3)pLysS Chemically Competent E. coli &lt;br /&gt;
| 10 × 50 µl&amp;lt;br&amp;gt; &lt;br /&gt;
| id=&amp;quot;price6&amp;quot; | 165.83 USD&amp;lt;br&amp;gt;&lt;br /&gt;
|-&lt;br /&gt;
| C6070-03 &lt;br /&gt;
| BL21-AI™ One Shot® Chemically Competent E. coli &lt;br /&gt;
| 20 × 50 µl&amp;lt;br&amp;gt; &lt;br /&gt;
| id=&amp;quot;price7&amp;quot; | 322.61 USD&amp;lt;br&amp;gt;&lt;br /&gt;
|-&lt;br /&gt;
| C6565-03 &lt;br /&gt;
| One Shot® BL21(DE3)pLysE Chemically Competent E. coli &lt;br /&gt;
| 20 × 50 µl&amp;lt;br&amp;gt; &lt;br /&gt;
| id=&amp;quot;price8&amp;quot; | 258.29 USD&amp;lt;br&amp;gt;&lt;br /&gt;
|- id=&amp;quot;addButton_9950&amp;quot;&lt;br /&gt;
| colspan=&amp;quot;5&amp;quot; | &amp;lt;br&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
&amp;lt;br&amp;gt;&amp;lt;/div&amp;gt;&lt;br /&gt;
== Genotypes ==&lt;br /&gt;
&lt;br /&gt;
{| width=&amp;quot;100%&amp;quot; cellspacing=&amp;quot;0&amp;quot; align=&amp;quot;&amp;quot; summary=&amp;quot;&amp;quot;&lt;br /&gt;
|-&lt;br /&gt;
! valign=&amp;quot;top&amp;quot; | Genotype &lt;br /&gt;
! valign=&amp;quot;top&amp;quot; | Description&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;100&amp;quot; | &lt;br /&gt;
ara-14&amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
| &lt;br /&gt;
Blocks arabinose catabolism&amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;100&amp;quot; | &lt;br /&gt;
argF&amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
| &lt;br /&gt;
Ornithine carbamoyltransferase mutation blocks ability to use arginine&amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;100&amp;quot; | &lt;br /&gt;
dam/dcm&amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
| &lt;br /&gt;
Abolishes endogenous adenine methylation at GATC sequences &lt;br /&gt;
&lt;br /&gt;
(dam) or cytosine methylation at CCWGG sequences (dcm). Used to propagate DNA for cleavage with certain restriction enzymes (e.g. Ava &lt;br /&gt;
II, Bcl I)&amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;100&amp;quot; | &lt;br /&gt;
DE3&amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
| &lt;br /&gt;
Lysogen that encodes T7 RNA polymerase. Used to induce expression in T7-driven expression systems&amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;100&amp;quot; | &lt;br /&gt;
endA&amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
| &lt;br /&gt;
endA Mutation in the non-specific endonuclease Endonuclease I; &lt;br /&gt;
&lt;br /&gt;
eliminates non-specific endonuclease activity, resulting in improved &lt;br /&gt;
plasmid preps&amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;100&amp;quot; | &lt;br /&gt;
F´ &amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
| &lt;br /&gt;
A self-transmissible, low-copy plasmid used for the generation &lt;br /&gt;
&lt;br /&gt;
of single-stranded DNA when infected with M13 phage; may contain a resistance marker to allow maintenance and will often carry the lacI &lt;br /&gt;
and lacZ∆M15 genotypes&amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;100&amp;quot; | &lt;br /&gt;
galK&amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
| &lt;br /&gt;
Galactokinase mutation blocks catabolism of galactose—cells &lt;br /&gt;
&lt;br /&gt;
that are galK minus grow in the presence of galactose as the sole &lt;br /&gt;
carbon source&amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;100&amp;quot; | &lt;br /&gt;
galU&amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
| &lt;br /&gt;
Glucose-1-phosphate uridylyltransferase mutation blocks &lt;br /&gt;
&lt;br /&gt;
ability to use galactose—cells that are galU minus can grow on media &lt;br /&gt;
that contains galactose as the sole carbon source&amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;100&amp;quot; | &lt;br /&gt;
gyrA96 &amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
| &lt;br /&gt;
DNA gyrase mutant produces resistance to nalidixic acid&amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;100&amp;quot; | &lt;br /&gt;
hsd &amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
| &lt;br /&gt;
Mutations in the system of methylation and restriction that &lt;br /&gt;
&lt;br /&gt;
allow E. coli to recognize DNA as foreign. The hsd genotype allows efficient transformation of DNA generated from PCR reactions &lt;br /&gt;
&lt;br /&gt;
*hsdR–eliminates restriction of unmethylated EcoK I sites. (1) &lt;br /&gt;
**hs&amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;100&amp;quot; | &lt;br /&gt;
lacI &amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
| &lt;br /&gt;
Encodes the lac repressor that controls expression from &lt;br /&gt;
&lt;br /&gt;
promoters that carry the lac operator; IPTG binds the lac repressor and derepresses the promoter; often used when performing blue/white &lt;br /&gt;
screening or to control expression of recombinant genes&amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;100&amp;quot; | &lt;br /&gt;
lacY1 &amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
| &lt;br /&gt;
Blocks use of lactose via β-D-galactosidase mutant&amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;100&amp;quot; | &lt;br /&gt;
lacZ &amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
| &lt;br /&gt;
β-D-galactosidase gene; mutations yield colorless (vs. blue) colonies in the presence of X-gal&amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;100&amp;quot; | &lt;br /&gt;
lacZ∆M15 &amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
| &lt;br /&gt;
Element required for β-galactosidase complementation when &lt;br /&gt;
&lt;br /&gt;
plated on X-gal; used in blue/white screening of recombinants; usually &lt;br /&gt;
carried on the lambdoid prophage φ80 or F´&amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;100&amp;quot; | &lt;br /&gt;
leuB &amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
| &lt;br /&gt;
Requires leucine for growth on minimal media via β-isopropyl malate dehydrogenase mutation&amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;100&amp;quot; | &lt;br /&gt;
lon &amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
| &lt;br /&gt;
lon Deficiency in the Lon ATPase-dependent protease; decreases &lt;br /&gt;
&lt;br /&gt;
the degradation of recombinant proteins; all B strains carry this &lt;br /&gt;
mutation&amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;100&amp;quot; | &lt;br /&gt;
mcrA, mcrBC,or mrr&amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
| &lt;br /&gt;
Mutations that allow methylated DNA to not be recognized as &lt;br /&gt;
&lt;br /&gt;
foreign; this genotype is necessary when cloning genomic DNA or &lt;br /&gt;
methylated cDNA &amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;100&amp;quot; | &lt;br /&gt;
nupG &amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
| &lt;br /&gt;
Mutation for the transport of nucleosides&amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;100&amp;quot; | &lt;br /&gt;
ompT &amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
| &lt;br /&gt;
Indicates that the E. coli lack an outer membrane &lt;br /&gt;
&lt;br /&gt;
protease—reduces degradation of heterologous the strains and recovery &lt;br /&gt;
of intact recombinant proteins is improved in ompT minus strains&amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;100&amp;quot; | &lt;br /&gt;
P3 &amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
| &lt;br /&gt;
A 60-kb low-copy plasmid that carries the ampicillin and &lt;br /&gt;
&lt;br /&gt;
tetracycline resistance genes with amber mutations; used predominantly for selection of supF-containing plasmids; carries the kanamycin &lt;br /&gt;
resistance gene for selection&amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;100&amp;quot; | &lt;br /&gt;
pLys &amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
| &lt;br /&gt;
pLys Plasmid that encodes T7 lysozyme; used to reduce basal &lt;br /&gt;
&lt;br /&gt;
expression in T7-driven expression systems by inhibiting basal levels &lt;br /&gt;
of T7 RNA polymerase&amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;100&amp;quot; | &lt;br /&gt;
proAB &amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
| &lt;br /&gt;
proAB Requires proline for growth on minimal media&amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;100&amp;quot; | &lt;br /&gt;
recA &amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
| &lt;br /&gt;
Mutation in a gene responsible for general recombination of DNA; particularly desirable when cloning genes with direct repeats&amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;100&amp;quot; | &lt;br /&gt;
relA &amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
| &lt;br /&gt;
RNA is synthesized in absence of protein synthesis (relaxed &lt;br /&gt;
&lt;br /&gt;
phenotype) relA locus regulates the coupling between transcription and translation. In the wild type, limiting amino acid concentrations &lt;br /&gt;
results in the shutdown of RNA synthesis (also known as th&amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;100&amp;quot; | &lt;br /&gt;
rpsL&amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
| &lt;br /&gt;
Confers resistance to streptomycin (this makes a mutant ribosomal protein, small subunit, the target of the drug)&amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;100&amp;quot; | &lt;br /&gt;
supE,F&amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
| &lt;br /&gt;
tRNA glutamine suppressor of amber (supE)(UAG) or tyrosine (supF)&amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;100&amp;quot; | &lt;br /&gt;
thi-1 &amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
| &lt;br /&gt;
Requires thiamine for growth on minimal media&amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;100&amp;quot; | &lt;br /&gt;
Tn10 &amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
| &lt;br /&gt;
Confers tetracycline resistance via a transposon&amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;100&amp;quot; | &lt;br /&gt;
tonA&amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
| &lt;br /&gt;
Confers resistance to the lytic bacteriophage T1, T5 and f80&amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;100&amp;quot; | &lt;br /&gt;
traD, D36 &amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
| &lt;br /&gt;
Prevents transfer of F&amp;#039; episome via transfer factor mutation&amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;100&amp;quot; | &lt;br /&gt;
tsx &amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
| &lt;br /&gt;
Confers resistance to phage T6 and colicin K&amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;100&amp;quot; | &lt;br /&gt;
xyl-5 &amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
| &lt;br /&gt;
Blocks catabolism of xylose&amp;amp;nbsp;&lt;br /&gt;
&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
[[Category:Knowledgebase]]&lt;/div&gt;</summary>
		<author><name>Paul.xu</name></author>
	</entry>
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