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Genetic Code Expansion


The genetic code for all life is based upon four nucleotides, 64 codons, and 20 amino acids. Yet in the past two decades, biologists have expanded the genetic code by redirecting specific codons to encode amino acids beyond the 20 standard amino acids.

Expanding the Genetic Code

In protein translation, an aminoacyl-tRNA synthetase (aaRS) loads its cognate tRNA with a specific amino acid. Then, the tRNA is pulled into the ribosome and if the anticodon on the tRNA can bind to the mRNA (hence, the anticodon is complementary to the codon), the amino acid from the tRNA is incorporated into the growing peptide chain.

To expand the genetic code, modified tRNAs, codons, and tRNA synthetases are introduced into the cell on plasmids and the new amino acid is introduced in the media. Generally, you will need two plasmids, as depicted in the figure below:

  1. A plasmid expressing the tRNA and its cognate aminoacyl-tRNA-synthetase (aaRS) that has been evolved to incorporate non-canonical amino acids (ncAAs).

  2. A plasmid containing the gene of interest with the modified codon (typically the amber codon) that is recognized by the cognate charged tRNA.

  3. Once these plasmids have been introduced in the cells, the non-canonical amino acid can be incorporated using the existing protein translation machinery.


To expand the genetic code, 4 major changes to the standard translation machinery are needed in order to incorporate a non-canonical amino acid into the protein of interest:

  1. The non-canonical amino acid, which is generally introduced in the media.
  2. A new codon to be allocated to the new amino acid. Because there are no free codons, this can be challenging. In E.coli, the rarest codon is the amber stop codon (UAG) and thus this codon is often used. The gene of interest can be expressed from a plasmid containing a UAG codon at the place where the new amino acid would be incorporated. Other options, such a 4-base pair codons, have also been utilized.
  3. A tRNA that recognizes this codon.
  4. An aminoacyl-tRNA synthetase to load the new amino acid onto the tRNA. The tRNA and synthetase are called an orthogonal set, because they should not crosstalk with the endogenous tRNA and synthetase sets. Many of these sets are derived from M. jannaschii, M. barkeri, or E.coli and can be mutated and screened through directed evolution to charge the tRNA with a different amino acid. They are typically expressed from a single plasmid, with multiple copies of the tRNA.

Applications

By making small changes in selected amino acids within a protein, any alterations in structure or function in the protein can be observed. The introduced amino acid can also be used to intentionally change the activity of a protein (e.g. converting a DNA binding protein to a DNA cleaving enzyme) or to regulate the activity of a protein so that it is responsive to specific stimuli, such as light. On a broader scale, the expanded genetic code can help us understand and evolve proteins for various purposes from therapeutics to biopolymers.

Tips for Success

Before beginning to reprogram the genetic code, there are several things to consider. If you are working off of a previously established protocol, make sure to match the growth medium, ncAA concentration, and the cell lines used previously.

Remember that the orthogonal pairs of synthetase and tRNA that work for one organism may not work for another. The orthogonal synthetase must aminoacylate only the orthogonal tRNA, and not endogenous ones. Endogenous synthetases cannot aminoacylate the orthogonal tRNA. And the orthogonal tRNA has to bind to an unallocated codon. Therefore many controls must be used to make sure that these conditions are true. Always express first with a control reporter gene – GFP for E. coli or mCherry-GFP for mammalian cells. You should also express the protein with and without the ncAA in the media to make sure that the full length protein is only made when the ncAA is included.

Browse Synthetase Plasmids

The table below highlights plasmids that contain aminoacyl tRNA synthetase for use in E.coli and Mammalian Cells. Many of the plasmids also contain one or more copies of the cognate tRNA gene.

ID Plasmid Synthetase Origin ncAA Expression Codon PI
64915 pMAH-POLY tyrosyl-tRNA synthetase E. coli pBof Mammalian TAG Huiwang Ai
71403 pCMV-DnpK PylRS M. barkeri N6‐(2‐(2,4‐dinitrophenyl)acetyl)lysine (DnpK) Bacterial, Mammalian TAG Huiwang Ai
71404 pMAH2-CageCys leucyl-tRNA-synthetase E. coli photocaged cysteine Mammalian TAG Huiwang Ai
153557 pEvol-MjaYRS MJaYRS M. jannaschii 3-aminotyrosine Bacterial TAG Huiwang Ai
153558 pMAH-EcaYRS EcaYRS E. coli 3-aminotyrosine Mammalian Huiwang Ai
157925 pMAH-POLY-eRF1(E55D) POLY-eRF1(E55D) E. coli para-substituted phenylalanine analogs Mammalian TAG Huiwang Ai
92047 pCOTS-pyl-GFP(35TAG) PylRS M. mazei Cyanobacterial TAG Lital Alfonta
92048 gCOTS-pyl PylRS M. mazei Cyanobacterial TAG Lital Alfonta
160041 pRaGE Pyl TAG GFP Y35TAG PylRS M. mazei Bacterial TAG Lital Alfonta
160089 pPaGE Pyl TAG FliC T248TAG PylRS M. mazei Bacterial TAG Lital Alfonta
182881 Mut1-RS tyrosyl-tRNA synthetase M. jannaschii 4-propargyloxy-l-phenylalanine (pPR) Bacterial TAG Miriam Amiram
182882 Mut2-RS tyrosyl-tRNA synthetase M. jannaschii 4-propargyloxy-l-phenylalanine (pPR) Bacterial TAG Miriam Amiram
182884 AzoRS-4 tyrosyl-tRNA synthetase M. jannaschii azobenzene-bearing uAAs Bacterial TAG Miriam Amiram
113644 pRF0G-Tyr tyrosyl-tRNA synthetase M. jannaschii tyrosine Bacterial TAG Jeffrey Barrick
113645 pRF0G-IodoY iodotyrosine tRNA synthetase M. jannaschii iodotyrosine Bacterial TAG Jeffrey Barrick
91705 pSupAR-MbPylRS(DiZPK) PylRS M. barkeri photocrosslinkers DiZPK, DiZSeK, or DiZHSeC Bacterial TAG P. Chen
91706 pCMV-MbPylRS(DiZPK) PylRS M. barkeri photocrosslinkers DiZPK, DiZSeK, or DiZHSeC Mammalian TAG P. Chen
173897 SepRS(2)/pSertRNA(B4)/EF-Sep aminoacyl-tRNA synthetase M. maripaludis phosphoserine Bacterial Jason W Chin
174515 pMB1_MmPylRS_MmtRNA-Pyl-opt(UGA) PylRS M. mazei Bacterial TGA Jason W Chin
174516 pMB1_1R26PylRS(CbzK)_AfTyrRS(p-I-Phe)_AlvtRNA-ΔNPyl(8)(CGA)_AftRNA-Tyr(A01)(CUA) 1R26PylRS and AfTyrRS CbzK and p-I-Phe Bacterial TCG and TAG Jason W Chin
105829 pIRE4-Azi Azi-tRNA synthetase (EAziRS) p-Azido-phenylalanine (Azi) Mammalian TAG Irene Coin
105830 pNEU-hMbPylRS-4xU6M15 PylRS M. barkeri Pyl-like click amino acids, tRNA M15 Mammalian TAG Irene Coin
140009 pAS_4xMma PylT_FLAG-Mma PylRS PylRS M. mazei CpK, AbK Mammalian TAG Simon Elsaesser
140011 pAS_4xMx PylT_FLAG-Mx PylRS PylRS M. alvus CpK Mammalian TAG Simon Elsaesser
140012 pAS_4xMx PylT_FLAG-Mx PylRS YA PylRS YA M. alvus Mammalian TAG Simon Elsaesser
140013 pAS_4xMx PylT C41CA_FLAG_Mx PylRS PylRS M. alvus Mammalian TAG Simon Elsaesser
140014 pAS_4xMx PylT C41CA_FLAG_Mx PylRS YA PylRS M. alvus Mammalian TAG Simon Elsaesser
140018 pAS_4xBstTyrT(CUA)_EcoTyrRS-FLAG tyrosyl-tRNA synthetase E. coli Mammalian TAG Simon Elsaesser
140019 pAS_4xEcoLeuT(CUA)_AnapRS AnapRS E. coli azido-phenylalanine Mammalian TAG Simon Elsaesser
140020 pAS_4xMma PylT_FLAG-AbKRS-chIPYE chimeric PylRS Chimeric photo-crosslinking-lysine Mammalian TAG Simon Elsaesser
140021 pAS_4xMma PylT_FLAG-AcKRS AcKRS M. mazei acetyl-lysine Mammalian TAG Simon Elsaesser
140022 pAS_4xMma PylT_FLAG-PcKRS PcKRS M. barkeri photocaged-lysine Mammalian TAG Simon Elsaesser
140023 pAS_4xMma PylT_FLAG-Mma PylRS AF PylRS AF M. mazei Mammalian TAG Simon Elsaesser
154762 pAS_FLAG-Mma PylRS PylRS M. mazei Mammalian TAG Simon Elsaesser
154763 pAS_FLAG-G1 PylRS G1 PylRS M. archaeon Mammalian TAG Simon Elsaesser
154764 pAS_FLAG-Mx1201 PylRS PylRS M. alvus Mammalian TAG Simon Elsaesser
154768 pAS_4xG1 PylT FLAG-G1 PylRS G1 PylRS M. archaeon Mammalian TAG Simon Elsaesser
154769 pAS_4xG1 PylT FLAG-G1 PylRS Y125A G1 PylRS Y125A M. archaeon Mammalian TAG Simon Elsaesser
154773 pAS_4xhybPylT A41AA C55A FLAG-G1 PylRS Y125A G1 PylRS Y125A M. archaeon Mammalian TAG Simon Elsaesser
154774 pAS_4xU6-PylT M15 (UUA) FLAG-Mma PylRS PylRS M. mazei Mammalian TAA Simon Elsaesser
174890 pAS_8xMmaPylT_EF1_FLAG-MmaPylRS PylRS M. mazei Mammalian TAG Simon Elsaesser
122650 Mm-PylRS-AF/Pyl-tRNACUA PylRS M. mazei trans-cyclooct- 2-ene-lysine (TCOK) Mammalian TAG Howard Hang
163915 pRSF-ChPylTMSK ChPylTMSK N6-(((Trimethylsilyl)methoxy)carbonyl)-L-lysine (TMSK) Bacterial TAG Thomas Huber
163916 pXPR-SF61 SF5Phe tRNA synthetase para-Pentafluorosulfanyl-Phenylalanine Bacterial TAG Thomas Huber
174718 pRSF-G1mCNPRS G1mCNPRS M. archaeon L-3-(2-cyano-4-pyridyl)alanine (mCNP) Bacterial TAG Thomas Huber
174719 pRSF-G1pCNPRS G1pCNPRS M. archaeon L-3-(2-cyano-5-pyridyl)alanine (pCNP) Bacterial TAG Thomas Huber
177310 pRSF-G1(7FTrp)RS PylRS M. archaeon 7-Fluoro-L-Tryptophan (7FTrp) Bacterial TAG Thomas Huber
177311 pRSF-G1TFAKRS M. archaeon N6-(trifluoroacetyl)-L-lysine (TFA-Lys) Bacterial TAG Thomas Huber
198323 pRSF-G1TMSNKRS M. archaeon TMSNK Bacterial TAG Thomas Huber
73544 pEvol-pAcFRS.2.t1 pAcFRS.2.t1 E. coli p-acetyl-l-phenylalanine (pAcF) Bacterial TAG Farren Isaacs
73545 pEvol-pAcFRS.1.t1 pAcFRS.1.t1 E. coli p-acetyl-l-phenylalanine (pAcF) Bacterial TAG Farren Isaacs
73546 pEvol-pAzFRS.2.t1 pAzFRS.2.t1 E. coli p-azido-l-phenylalanine (pAzF) Bacterial TAG Farren Isaacs
73547 pEvol-pAzFRS.1.t1 pAzFRS.1.t1 E. coli p-azido-l-phenylalanine (pAzF) Bacterial TAG Farren Isaacs
197930 pSUP-(2xCouRS-tRNAopt) 7-HCou Aminoacyl (7-hydroxy-4-coumarin-yl) ethylglycine Bacterial TAG Kenneth Johnson
82417 pUltra-sY sY-specific aaRS M. jannaschii sulfotyrosine (sY) Bacterial, Plant TAG Chang Liu
104069 pTECH-chAcK3RS(IPYE) AcK3RS Chimeric Nε-acetyl-L-lysine Bacterial TAG David Liu
104070 pTECH-MbAcK3RS(IPYE) AcK3RS M. barkeri Nε-acetyl-L-lysine Bacterial TAG David Liu
104071 pTECH-MmAcK3RS(IPYE) AcK3RS M. mazei Nε-acetyl-L-lysine Bacterial TAG David Liu
104072 pTECH-MbPylRS(IPYE) PylRS M. barkeri m-iodo-L-phenylalanine Bacterial TAG David Liu
104073 pTECH-MmPylRS(IPYE) PylRS M. mazei m-iodo-L-phenylalanine Bacterial TAG David Liu
127411 pEVOL-pylT-N346A/C348A PylRS M. mazei mono-substituted phenylalanine derivatives and tyrosinyl ethers Bacterial TAG Wenshe Liu
127415 pEVOL-AcKRS-CloDF PylRS M. mazei acyl-lysine derivatives Bacterial Wenshe Liu
127445 pEDF-PhdRS PylRS N346A-C348A M. mazei Bacterial Wenshe Liu
137908 PylRS-AS PylRS M. mazei fluorophenylalanine derivatives Bacterial TAG Wenshe Liu
137976 pEVOL-AckRS PylRS M. mazei AzHeK Bacterial TAG Wenshe Liu
164080 pCMV-MtPylRS (human-opti) PylRS M. thermophila acetyl-lysine Mammalian Tao Liu
164081 pCMV-MfPylRS (human-opti) PylRS M. flavescens acetyl-lysine Mammalian Tao Liu
164195 pCMV-MtAcKRS (human-opti) AcKRS M. thermophila acetyl-lysine Mammalian Tao Liu
164196 pCMV-MfBulKRS (human-opti) BulKRS M. flavescens acetyl-lysine Mammalian Tao Liu
172482 pEVOL-pylT-AznLRS AznLRS M. mazei azidonorleucine Bacterial TAG Wenshe Liu
182537 pEVOL-MmAcKRS1-PylTUUA PylRS M. mazei Bacterial TAA Wenshe Liu
85484 pDule-tfmF A65V S158A tri-fluoromethyl-phenylalanine synthetase M. jannaschii family of [19]F-UAAs Bacterial TAG Ryan Mehl
85494 pDule-pCNF para-cyanophenylalanine synthetase M. jannaschii azidoPhenylalanine Bacterial TAG Ryan Mehl
85495 pDule2-pCNF para-cyanophenylalanine synthetase M. jannaschii azidoPhenylalanine Bacterial TAG Ryan Mehl
85496 pDule-Tet2.0 Tetrazine2.0 tRNA synthetase M. jannaschii Tetrazine 2.0 Bacterial TAG Ryan Mehl
85497 pDule2-Tet2.0 Tetrazine2.0 tRNA synthetas M. jannaschii Tetrazine 2.0 Bacterial TAG Ryan Mehl
85498 pDule-3-nitroTyrosine (5B) 3NY (5B) synthetase M. jannaschii 3-nitroTyrosine Bacterial TAG Ryan Mehl
85499 pDule2-3-nitroTyrosine (5B) 3NY (5B) synthetase M. jannaschii 3-nitroTyrosine Bacterial TAG Ryan Mehl
85500 pDule-IBBN (G2) IBBN (G2) synthetase M. jannaschii 4-(2′-bromoisobutyramido)-phenylalanine (IBBN) and structurally analogous amino acids Bacterial TAG Ryan Mehl
85501 pDule2-IBBN (G2) IBBN (G2) synthetase M. jannaschii 4-(2′-bromoisobutyramido)-phenylalanine (IBBN) and structurally analogous amino acids Bacterial TAG Ryan Mehl
85502 pDule-para-aminoPhe pAF synthetase M. jannaschii para-aminoPhe Bacterial TAG Ryan Mehl
85503 pDule2-para-aminoPhe pAF synthetase M. jannaschii para-aminoPhe Bacterial TAG Ryan Mehl
141173 pAcBac1-3nitroY-A7-RS A7 3nY tRNA synthetase M. barkeri Mammalian Ryan Mehl
141174 pAcBac1-haloTyrRS C6 C6 HaloTyrosine tRNA synthatase E. coli Mammalian Ryan Mehl
160377 pDule-Mb haloTyrRS C6 C6 HaloTyrosine tRNA synthatase M. barkeri Halotyrosine Amino Acids Bacterial TAG Ryan Mehl
160378 pDule2-Mb haloTyrRS C6 C6 HaloTyrosine tRNA synthatase M. barkeri Halotyrosine Amino Acids Bacterial TAG Ryan Mehl
164579 pEVOL-pAzF[TAG] pCNFRS M. jannaschii pAzF, pCNF, or pENF Bacterial TAG Ryan Mehl
164580 pUltraI-Tet3.0[TAA] Tet3.0RS M. barkeri Tet3.0 Bacterial TAA Ryan Mehl
174078 pDule-3-nitroTyrosine (A7) 3NY (A7) synthetase M. jannaschii 3-nitroTyrosine Bacterial TAG Ryan Mehl
174079 pDule2-3-nitroTyrosine (A7) 3NY (A7) synthetase M. jannaschii 3-nitroTyrosine Bacterial TAG Ryan Mehl
174080 pDule-Tet3.0 Tet3.0 tRNA synthetase M. barkeri Tetrazine 3.0 Bacterial TAG Ryan Mehl
174081 pAcBac1-NES-Flag-R2-84-MbRS Tetrazine3.0 NES-Flag-R2-84 tRNA synthetase M. barkeri Tetrazine 3.0 Mammalian Ryan Mehl
174099 pDule-Acd82 Acridone 82 tRNA synthetase M. barkeri acridone Bacterial TAG Ryan Mehl
174100 pDule2-Acd82 Acridone 82 tRNA synthetase M. barkeri acridone Bacterial TAG Ryan Mehl
174101 pAcBac1.tR4-AcdRS82 Acridone 82 tRNA synthetase M. barkeri acridone Mammalian Ryan Mehl
197566 pAcBac1-Ma-Acridone-RS1 (A7) PylRS M. alvus acridonyl-alanine Mammalian TAG Ryan Mehl
197573 pBK- Ma PylRS WT PylRS M. alvus Bacterial Ryan Mehl
197576 pAcBac1-Mb-Fluoro-Phe B5 Pyl Fluoro-Phe B5 M. barkeri fluorinated phenylalanine derivatives Mammalian TAG Ryan Mehl
197577 pAcBac1-Mb-Fluoro-Phe D6 Pyl Fluoro-Phe D6 M. barkeri fluorinated phenylalanine derivatives Mammalian TAG Ryan Mehl
197651 pDule- Mj Acd A9 Acd-A9 M. jannaschii acridone Bacterial TAG Ryan Mehl
197652 pDule2 - Mj Acd A9 Acd-A9 M. jannaschii acridone Bacterial TAG Ryan Mehl
201922 pERM2-nhpSer SepRS M. maripaludis non-hydrolyzable phosphoserine Bacterial TAG Ryan Mehl
126035 pEVOL-ABK PylRS M. barkeri 3’-azibutyl-N-carbamoyl-lysine (AbK) Bacterial TAG Andrea Musacchio
182287 pcDNA3.1(+)_U6 tRNAPyl_CMV NESPylRS(AF) Y306A/Y384F (AF) pyrrolysine (Pyl) tRNA synthetase M. mazei Mammalian TAG Ivana Nikić-Spiegel
182652 pcDNA3.1(+)_4x(U6 tRNA M15)_CMV NESPylRS(AF) Y306A/Y384F (AF) pyrrolysine (Pyl) tRNA synthetase M. mazei Mammalian TAG Ivana Nikić-Spiegel
182653 pcDNA3.1(+)_U6 tRNAPyl_CMV NESPylRS(AF)_IRES_eRF1(E55D)-HA Y306A/Y384F (AF) pyrrolysine (Pyl) tRNA synthetase M. mazei Mammalian TAG Ivana Nikić-Spiegel
68292 SepOTSλ SepRS9 E. coli Sep Bacterial TAG Jesse Rinehart
188537 pSerOTS-C1* (V70) SerRS M. maripaludis Phosphoserine Bacterial TAG Jesse Rinehart
196486 pcPylRS(Y384F Y306A) PylRS(Y384F Y306A) M. mazei Z-Lys or Azido-Z-Lys Mammalian TAG Kensaku Sakamoto
197099 pIYN3 TyrRS M. jannaschii halogenated tyrosines Bacterial TAG Kensaku Sakamoto
197100 pCDF-Mm2 PylRS M. mazei pyrrolysine derivatives Bacterial TAG Kensaku Sakamoto
197101 pCDF-Az TyrRS M. jannaschii azidophenylalanine Bacterial TAG Kensaku Sakamoto
197102 pBpaRS3tRNA TyrRS M. jannaschii p-benzoylphenylalanine Bacterial TAG Kensaku Sakamoto
200225 pMega-MaPylRS PylRS M. alvus Nε-Boc-lysine Bacterial TAG Alanna Schepartz
200226 pMega-MaFRSA PylRS M. alvus meta-trifluoromethylphenylalanine Bacterial TAG Alanna Schepartz
31186 pEVOL-pAzF p-azidohenylalanine RS M. jannaschii p-azido-l-phenylalanine Bacterial TAG Peter Schultz
31190 pEVOL-pBpF p-benzoylphenylalanine RS M. jannaschii p-benzoyl-l-phenylalanine Bacterial TAG Peter Schultz
48215 pULTRA-CNF tyrosyl-tRNA synthetase M. jannaschii para-cyanophenylalanine (pCNPhe) Bacterial TAG Peter Schultz
48696 pANAP AnapRS E. coli fluorescent AA, Anap Mammalian TAG Peter Schultz
49086 pDULE-ABK PylRS M. barkeri aliphatic diazirine amino acid Bacerial, Mammalian TAG Peter Schultz
50831 pAcBac2.tR4-OMeYRS/GFP* tyrosyl-tRNA synthetase E. coli various unnatural amino acids Mammalian TAG Peter Schultz
50832 pAcBac1.tR4-MbPyl PylRS M. barkeri variety of unnatural amino acids Mammalian TAG Peter Schultz
193250 pMV361_MjTyrRS tyrosyl-tRNA synthetase M. jannaschii Bacterial TAG Peter Schultz
99222 pTECH-chPylRS(IPYE) PylRS Chimeric p-iodo-L-phenylalanine Bacterial TAG Dieter Söll
51401 pAM1 NLL-MetRS E. coli azi-donorleucine (Anl) Bacterial ATG David Tirrell
62598 pKPY514 phenylalanyl-tRNA synthetase subunit E. coli p-azido-L-phenylalanine (Azf) C. elegans ATG David Tirrell
62599 pKPY197 phenylalanyl-tRNA synthetase (CePheRS) C.elegans p-azido-L-phenylalanine (Azf) C. elegans ATG David Tirrell
63177 pMarsL274G methionyl-tRNA synthetase (L274GMmMetRS) M. musculus azidonorleucine (Anl) Mammalian ATG David Tirrell
89189 pMaRSC methionyl-tRNA synthetase (L274GMmMetRS) M. musculus azidonorleucine (Anl) Mammalian ATG David Tirrell

Browse Strains

The table below highlights bacteria strains that have been modified to enhance non-standard amino acid incorporation.

   ID Strain Description PI
48998 C321.ΔA all TAG sites changes to UAG, RF1 function removed George Church
48999 C321 all TAG sites changes to UAG George Church
49018 C321.ΔA.exp all TAG sites changes to UAG, RF1 function removed, MutS restored so decreased mutation rate George Church
68306 C321.ΔA all TAG sites changes to UAG, RF1 function removed, deletion of SerB to maintain sufficient levels of Sep in the cytoplasm for protein synthesis. Also see Strain 192872. Jesse Rinehart
69493 MCJ.559 TAG sites, RF1 function removed, genomic deletions for improved incorporation Michael Jewett
69495 rEc.13.delA 13 amber sites changed to TAA, RF1 function removed Michael Jewett
73581 C321.deltaA (Isaacs lab) all TAG sites changes to UAG, RF1 function removed Farren Isaacs
87359 C321.∆A.opt all TAG sites changes to UAG, RF1 function removed, improved doubling time. George Church
98564 C321.Ub-UAG-sfGFP all TAG sites changes to UAG, RF1 function removed, with Ubiquitin-UAG-sfGFP reporter George Church
98565 C321.ΔClpS.Ub-UAG-sfGFP all TAG sites changes to UAG, RF1 function removed, ClpS inactivated, with Ubiquitin-UAG-sfGFP reporter George Church
174513 Syn61 No TCG, TCA, or TAG codons in all open reading frames Jason W Chin
174514 Syn61Δ3(ev5) No TCG, TCA, or TAG codons. Deletion of serT, serU, and prfA genes Jason W Chin
189857 Syn61Δ3(ev5) ΔrecA (ev1) No TCG, TCA, or TAG codons. Deletion of serT, serU, prfA, and recA genes George Church
192872 rEcoli XpS All 321 UAG codons changed to UAA. mutS+, λ-, ΔybhB-bioAB, ΔprfA, ΔserB mutations for improved yield and growth Jesse Rinehart
197655 B95(DE3) ΔA ΔfabR ΔserB 95 endogenous TAG codons mutated to TAA, RF1 (prfA) deleted, fabR spontaneously mutated, serB deleted for phosphoserine GCE. For expressing phosphoserine-containing proteins using genetic code expansion without buildup of prematurely truncated protein. Ryan Mehl
197656 BL21(DE3) ΔserC serC gene knocked out; for expressing proteins containing site-specific non-hydrolyzable phosphoserine Ryan Mehl

Browse Target Plasmids

The table below highlights plasmids that contain genes with modified codons for unnatural amino acid incorporation.

ID Plasmid Gene/Insert Vector Type PI