Price Information
| Cat No. | Plasmid Name | Availability | Buy one, get one free! (?) |
|---|---|---|---|
| V006797 | pMAL-c4x | In stock, 1 week for quality controls |
Two tubes of lyophilized plasmid will be delivered, each tube is about 5µg.
Basic Vector Information
The pMAL-4 vectors (Figure 1) provide a method for expressing and purifying a protein produced from a cloned gene or open reading frame. The cloned gene is inserted downstream from the malE gene of E. coli, which encodes maltose-binding protein (MBP), resulting in the expression of an MBP fusion protein (1,2). The MBP in these vectors has been engineered for tighter binding to amylose. The method uses the strong “tac” promoter and the malE translation initiation signals to give high-level expression of the cloned sequences (3,4), and a one-step purification of the fusion protein using MBP’s affinity for maltose (5). The vectors express the malE gene (with or without its signal sequence) fused to the lacZα gene. Restriction sites between malE and lacZα are available for inserting the coding sequence of interest. Insertion inactivates the β-galactosidase α-fragment activity of the malE-lacZα fusion, which results in a blue to white color change on Xgal plates when the construction is transformed into an α-complementing host such as TB1, JM107 or NEB 5-alpha Competent E. coli (6,7). When present, the signal peptide on pre-MBP directs fusion proteins to the periplasm. For fusion proteins that can be successfully exported, this allows folding and disulfide bond formation to take place in the periplasm of E. coli, as well as allowing purification of the protein from the periplasm (8). The vectors carry the lacIq gene, which codes for the Lac repressor. This keeps expression from Ptac low in the absence of IPTG induction. The pMAL-4 vectors also contain the sequence coding for the recognition site of a specific protease, located just 5´ to the polylinker insertion sites. This allows MBP to be cleaved from the protein of interest after purification. The pMAL-c4X and pMAL-p4X vectors that are included in the system encode the site for Factor Xa (9, 10). Factor Xa cleaves after its four amino acid recognition sequence, so that few or no vector-derived residues are attached to the protein of interest, depending on the site used for cloning. pMAL vectors containing sites for alternative proteases are also available (Figure 1). The vectors pMAL-c4G (NEB #N8106) and pMAL-p4G (NEB #N8103) encode the site for GenenaseI (NEB #P8075), which cleaves following the sequence His-Tyr. The vectors pMAL-c4E (NEB #N8105) and pMAL-p4E (NEB #N8102) encode the site for Enterokinase (NEB #P8070), which cleaves following the sequence Asp-Asp-Asp-Asp-Lys.
- Vector Name:
- pMAL-c4x
- Antibiotic Resistance:
- Ampicillin
- Length:
- 6645 bp
- Type:
- E. coli Expression Vectors
- Replication origin:
- ori
- Copy Number:
- High copy number
- Promoter:
- Tac
- Cloning Method:
- Enzyme digestion and ligation
- 5' Primer:
- MalE: 5'-GGTCGTCAGACTGTCGATGAAGCC-3'; MBP-F: 5'-gatgaagccctgaaagacgcgcag-3'
- 3' Primer:
- pBad-R: 5'-gatttaatctgtatcagg-3'; M13-F: 5'-TGTAAAACGACGGCCAGT-3'
- Fusion Tag:
- N-MBP, N-Factor Xa
pMAL-c4x vector Map
Plasmid Protocol
1. Centrifuge at 5,000×g for 5 min.
2. Carefully open the tube and add 20 μl of sterile water to dissolve the DNA.
3. Close the tube and incubate for 10 minutes at room temperature.
4. Briefly vortex the tube and then do a quick spin to concentrate the liquid at the bottom. Speed is less than 5000×g.
5. Store the plasmid at -20 ℃.
6. The concentration of plasmid re-measurement sometimes differs from the nominal value, which may be due to the position of the lyophilized plasmid in the tube, the efficiency of the re-dissolution, the measurement bias, and adsorption on the wall of the tube, therefore, it is recommended to transform and extract the plasmid before using it
General Plasmid Transform Protocol
1. Take one 100μl of the competent cells and thaw it on ice for 10min, add 2μl of plasmid, then ice bath for 30min, then heat-shock it at 42℃ for 60s, do not stir, and then ice bath for 2min.
2. Add 900μl of LB liquid medium without antibiotics, and incubate at 37℃ for 45min (30℃ for 1-1.5 hours) with 180rpm shaking.
3. Centrifuge at 6000rpm for 5min, leave only 100μl of supernatant to resuspend the bacterial precipitate and spread it onto the target plasmid-resistant LB plate.
4. Invert the plate and incubate at 37℃ for 14h, or at 30℃ for 20h.
5. Pick a single colony into LB liquid medium, add the corresponding antibiotics, incubate at 220rpm for 14h, and extract the plasmid according to the experimental needs and the instructions of the plasmid extraction kit.
pMAL-c4x vector Sequence
LOCUS Exported 6645 bp DNA circular SYN 10-SEP-2025
DEFINITION synthetic circular DNA
ACCESSION .
VERSION .
KEYWORDS .
SOURCE synthetic DNA construct
ORGANISM synthetic DNA construct
REFERENCE 1 (bases 1 to 6645)
AUTHORS 11111111
TITLE Direct Submission
FEATURES Location/Qualifiers
source 1..6645
/mol_type="other DNA"
/organism="synthetic DNA construct"
misc_feature 97..125
/label=tac promoter
/note="strong E. coli promoter; hybrid between the trp and
lac UV5 promoters"
protein_bind 133..149
/label=lac operator
/bound_moiety="lac repressor encoded by lacI"
/note="The lac repressor binds to the lac operator to
inhibit transcription in E. coli. This inhibition can be
relieved by adding lactose or
isopropyl-beta-D-thiogalactopyranoside (IPTG)."
CDS 219..1319
/codon_start=1
/gene="malE (mutated)"
/product="maltose binding protein from E. coli"
/label=MBP
/note="This version of the gene does not encode a signal
sequence, so MBP will remain in the cytosol."
/translation="MKIEEGKLVIWINGDKGYNGLAEVGKKFEKDTGIKVTVEHPDKLE
EKFPQVAATGDGPDIIFWAHDRFGGYAQSGLLAEITPDKAFQDKLYPFTWDAVRYNGKL
IAYPIAVEALSLIYNKDLLPNPPKTWEEIPALDKELKAKGKSALMFNLQEPYFTWPLIA
ADGGYAFKYENGKYDIKDVGVDNAGAKAGLTFLVDLIKNKHMNADTDYSIAEAAFNKGE
TAMTINGPWAWSNIDTSKVNYGVTVLPTFKGQPSKPFVGVLSAGINAASPNKELAKEFL
ENYLLTDEGLEAVNKDKPLGAVALKSYEEELVKDPRIAATMENAQKGEIMPNIPQMSAF
WYAVRTAVINAASGRQTVDEALKDAQT"
CDS 1368..1379
/codon_start=1
/product="Factor Xa recognition and cleavage site"
/label=Factor Xa site
/translation="IEGR"
primer_bind complement(1427..1443)
/label=M13 fwd
/note="common sequencing primer, one of multiple similar
variants"
terminator 1792..1878
/gene="Escherichia coli rrnB"
/label=rrnB T1 terminator
/note="transcription terminator T1 from the E. coli rrnB
gene"
terminator 1970..1997
/label=rrnB T2 terminator
/note="transcription terminator T2 from the E. coli rrnB
gene"
promoter 2016..2107
/gene="bla"
/label=AmpR promoter
CDS 2108..2968
/codon_start=1
/gene="bla"
/product="beta-lactamase"
/label=AmpR
/note="confers resistance to ampicillin, carbenicillin, and
related antibiotics"
/translation="MSIQHFRVALIPFFAAFCLPVFAHPETLVKVKDAEDQLGARVGYI
ELDLNSGKILESFRPEERFPMMSTFKVLLCGAVLSRVDAGQEQLGRRIHYSQNDLVEYS
PVTEKHLTDGMTVRELCSAAITMSDNTAANLLLTTIGGPKELTAFLHNMGDHVTRLDRW
EPELNEAIPNDERDTTMPVAMATTLRKLLTGELLTLASRQQLIDWMEADKVAGPLLRSA
LPAGWFIADKSGAGERGSRGIIAALGPDGKPSRIVVIYTTGSQATMDERNRQIAEIGAS
LIKHW"
rep_origin complement(3068..3523)
/direction=LEFT
/label=f1 ori
/note="f1 bacteriophage origin of replication; arrow
indicates direction of (+) strand synthesis"
rep_origin 3634..4222
/direction=RIGHT
/label=ori
/note="high-copy-number ColE1/pMB1/pBR322/pUC origin of
replication"
misc_feature 4408..4550
/label=bom
/note="basis of mobility region from pBR322"
CDS complement(4652..4843)
/codon_start=1
/gene="rop"
/product="Rop protein, which maintains plasmids at low copy
number"
/label=rop
/translation="MTKQEKTALNMARFIRSQTLTLLEKLNELDADEQADICESLHDHA
DELYRSCLARFGDDGENL"
promoter 5339..5416
/gene="lacI (mutant)"
/label=lacIq promoter
/note="In the lacIq allele, a single base change in the
promoter boosts expression of the lacI gene about 10-fold."
CDS 5417..6499
/codon_start=1
/gene="lacI"
/product="lac repressor"
/label=lacI
/note="The lac repressor binds to the lac operator to
inhibit transcription in E. coli. This inhibition can be
relieved by adding lactose or
isopropyl-beta-D-thiogalactopyranoside (IPTG)."
/translation="MKPVTLYDVAEYAGVSYQTVSRVVNQASHVSAKTREKVEAAMAEL
NYIPNRVAQQLAGKQSLLIGVATSSLALHAPSQIVAAIKSRADQLGASVVVSMVERSGV
EACKAAVHNLLAQRVSGLIINYPLDDQDAIAVEAACTNVPALFLDVSDQTPINSIIFSH
EDGTRLGVEHLVALGHQQIALLAGPLSSVSARLRLAGWHKYLTRNQIQPIAEREGDWSA
MSGFQQTMQMLNEGIVPTAMLVANDQMALGAMRAITESGLRVGADISVVGYDDTEDSSC
YIPPLTTIKQDFRLLGQTSVDRLLQLSQGQAVKGNQLLPVSLVKRKTTLAPNTQTASPR
ALADSLMQLARQVSRLESGQ"