pMAL-p4x vector (V000720)

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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-p4x
Antibiotic Resistance:
Ampicillin
Length:
6720 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
Growth Strain(s):
DH10B
Growth Temperature:
37℃

pMAL-p4x vector Map

pMAL-p4x6720 bp3006009001200150018002100240027003000330036003900420045004800510054005700600063006600lacIq promoterlacICAP binding sitetac promoterlac operatorMBPFactor Xa siteM13 fwdrrnB T1 terminatorrrnB T2 terminatorAmpR promoterAmpRM13 orioribomrop

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-p4x vector Sequence

LOCUS       40924_29746        6720 bp DNA     circular SYN 13-JAN-2022
DEFINITION  synthetic circular DNA.
ACCESSION   .
VERSION     .
KEYWORDS    .
SOURCE      synthetic DNA construct
  ORGANISM  synthetic DNA construct
REFERENCE   1  (bases 1 to 6720)
  TITLE     Direct Submission
REFERENCE   2  (bases 1 to 6720)
  AUTHORS   .
  TITLE     Direct Submission
COMMENT     SGRef: number: 1; type: "Journal Article"
FEATURES             Location/Qualifiers
     source          1..6720
                     /mol_type="other DNA"
                     /organism="synthetic DNA construct"
     promoter        3..80
                     /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             81..1160
                     /codon_start=1
                     /label=lacI
                     /note="lac repressor"
                     /translation="VKPVTLYDVAEYAGVSYQTVSRVVNQASHVSAKTREKVEAAMAEL
                     NYIPNRVAQQLAGKQSLLIGVATSSLALHAPSQIVAAIKSRADQLGASVVVSMVERSGV
                     EACKAAVHNLLAQRVSGLIINYPLDDQDAIAVEAACTNVPALFLDVSDQTPINSIIFSH
                     EDGTRLGVEHLVALGHQQIALLAGPLSSVSARLRLAGWHKYLTRNQIQPIAEREGDWSA
                     MSGFQQTMQMLNEGIVPTAMLVANDQMALGAMRAITESGLRVGADISVVGYDDTEDSSC
                     YIPPLTTIKQDFRLLGQTSVDRLLQLSQGQAVKGNQLLPVSLVKRKTTLAPNTQTASPR
                     ALADSLMQLARQVSRLESGQ"
     protein_bind    1176..1197
                     /label=CAP binding site
                     /note="CAP binding activates transcription in the presence
                     of cAMP."
     promoter        1406..1434
                     /label=tac promoter
                     /note="strong E. coli promoter; hybrid between the trp and
                     lac UV5 promoters"
     protein_bind    1442..1458
                     /label=lac operator
                     /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             1528..2703
                     /codon_start=1
                     /label=MBP
                     /note="maltose binding protein from E. coli"
                     /translation="MKIKTGARILALSALTTMMFSASALAKIEEGKLVIWINGDKGYNG
                     LAEVGKKFEKDTGIKVTVEHPDKLEEKFPQVAATGDGPDIIFWAHDRFGGYAQSGLLAE
                     ITPDKAFQDKLYPFTWDAVRYNGKLIAYPIAVEALSLIYNKDLLPNPPKTWEEIPALDK
                     ELKAKGKSALMFNLQEPYFTWPLIAADGGYAFKYENGKYDIKDVGVDNAGAKAGLTFLV
                     DLIKNKHMNADTDYSIAEAAFNKGETAMTINGPWAWSNIDTSKVNYGVTVLPTFKGQPS
                     KPFVGVLSAGINAASPNKELAKEFLENYLLTDEGLEAVNKDKPLGAVALKSYEEELVKD
                     PRIAATMENAQKGEIMPNIPQMSAFWYAVRTAVINAASGRQTVDEALKDAQT"
     CDS             2752..2763
                     /codon_start=1
                     /label=Factor Xa site
                     /note="Factor Xa recognition and cleavage site"
                     /translation="IEGR"
     primer_bind     complement(2811..2827)
                     /label=M13 fwd
                     /note="common sequencing primer, one of multiple similar 
                     variants"
     terminator      3176..3262
                     /label=rrnB T1 terminator
                     /note="transcription terminator T1 from the E. coli rrnB
                     gene"
     terminator      3354..3381
                     /label=rrnB T2 terminator
                     /note="transcription terminator T2 from the E. coli rrnB
                     gene"
     promoter        3400..3491
                     /label=AmpR promoter
     CDS             3492..4349
                     /codon_start=1
                     /label=AmpR
                     /note="beta-lactamase"
                     /translation="MSIQHFRVALIPFFAAFCLPVFAHPETLVKVKDAEDQLGARVGYI
                     ELDLNSGKILESFRPEERFPMMSTFKVLLCGAVLSRVDAGQEQLGRRIHYSQNDLVEYS
                     PVTEKHLTDGMTVRELCSAAITMSDNTAANLLLTTIGGPKELTAFLHNMGDHVTRLDRW
                     EPELNEAIPNDERDTTMPVAMATTLRKLLTGELLTLASRQQLIDWMEADKVAGPLLRSA
                     LPAGWFIADKSGAGERGSRGIIAALGPDGKPSRIVVIYTTGSQATMDERNRQIAEIGAS
                     LIKHW"
     rep_origin      complement(4394..4907)
                     /direction=LEFT
                     /label=M13 ori
                     /note="M13 bacteriophage origin of replication; arrow
                     indicates direction of (+) strand synthesis"
     rep_origin      5018..5606
                     /label=ori
                     /note="high-copy-number ColE1/pMB1/pBR322/pUC origin of 
                     replication"
     misc_feature    complement(5792..5934)
                     /label=bom
                     /note="basis of mobility region from pBR322"
     CDS             complement(6039..6227)
                     /codon_start=1
                     /label=rop
                     /note="Rop protein, which maintains plasmids at low copy
                     number"
                     /translation="VTKQEKTALNMARFIRSQTLTLLEKLNELDADEQADICESLHDHA
                     DELYRSCLARFGDDGENL"