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pBluescript II SK(+) plasmid map

The map of pBluescript II SK(+) (GenBank X52328.1): unique cutters, the features the annotation library finds and the primer sites, with sources shown.

Built and maintained by Mat Beale. Methods and sources · Reference checks · Contact

NCBI X52328.1, “pBluescript II SK(+) vector DNA, phagemid excised from lambda ZAPII”, 2,961 bp, circular. Shipped with the app: opening it sends nothing to NCBI.

The map is drawn from the maker's or publisher's NCBI record. A vendor's current map, or your own stock, may differ from this record at a few positions; parts of some records were taken from the published sequences of their parent plasmids, as the record states.

The map

Library features, the 8 enzymes of the cloning site that cut once, and the sequencing-primer sites. Pick a feature for its evidence.

Arrow keys move between features in map order; Enter says what the one in focus is; [ and ] step back and forward; Home and End go to the first and last.

Unique cutters

48 enzymes of the table cut this plasmid once (Host: dam⁺ dcm⁺).

AbsI, Acc65I, AccI, AflIII, AhdI, AleI, AlwNI, ApaI, BamHI, BsaAI, BsaHI, BsaI, BseYI, BsmFI, BstXI, BtgI, BtgZI, ClaI, DraIII, EagI, Eco53kI, EcoO109I, EcoRI, EcoRV, HincII, HindIII, KpnI, NaeI, NgoMIV, NmeAIII, NotI, NspI, PciI, PsiI, PspOMI, PspXI, PstI, SacI, SacII, SalI, SapI, ScaI, SmaI, SpeI, XbaI, XhoI, XmaI, XmnI

Depends on methylation (not recorded)

Enzymes with a site whose methylation sensitivity is not recorded: they may or may not cut, so they are not counted.

BsaJI, BsiEI, CviKI-1, Hpy188I, Hpy188III, MwoI, NlaIV, PspGI, StyD4I

Features

FeatureLocationStrandEvidence
f1 regioncomplement(3..458)reverseExact match
T7 promoter626..644forwardExact match
T3 promoter772..790forwardExact match
lac promotercomplement(817..938)reverseExact match
lac operatorcomplement(834..854)reverseExact match
CAP binding sitecomplement(901..938)reverseExact match
ColE1-type origin1158..1825forwardExact match
RNA I (ColE1-type copy-number control)1656..1762forwardMatch: 99.0% identity, 100.0% coverage, 1 mismatch, 0 gaps
AmpR (bla)complement(1973..2833)reverseMatch: 99.7% identity, 100.0% coverage, 2 mismatches, 0 gaps

Sequencing-primer sites

PrimerLocationStrandBinding
pUC/M13 Forward Primer573 to 596forwardExact
M13 Forward (−20)600 to 615forwardExact
T7 Promoter primer626 to 645forwardExact
M13 Reverse812 to 828reverseExact
pUC/M13 Reverse Primer812 to 833reverseExact

Whether the primer primes at this site is not assessed.

Numbers

  • Double-stranded weight: 1.82961 × 10⁶ g/mol (circular, no end groups).
  • 1 µg is 0.5466 pmol.
  • 1 ng is 3.291 × 10⁸ copies.

Next: pick a diagnostic digest

The digest picker finds the digests whose gels tell a correct construct from an empty or reversed one.

Computed when this page was built, from data release f2.e1.p1.

How it is computed

  • Feature annotation from the library. Local alignment with affine gaps, seeded by shared 12-base words and banded; match +2, mismatch -3, this app's parameters, checked against the Python reference (Biopython 1.88's PairwiseAligner in local mode); a gap of k bases scores -5 - 2(k - 1), so one long gap costs less than several short ones. Identity is identical columns over alignment columns, gaps included; coverage is the feature's aligned bases over its length. The exported local_alignment_score is this score, for re-deriving a call, not a quality measure; for a feature under 30 bases no alignment runs and the score is set to twice its length, the score a whole exact alignment would have. A coding feature the library finds carries the /transl_table of the record it was taken from where that record names a genetic code other than genetic code 1, and carries none otherwise. Attribution to the original publications not yet checked.Checked against Biopython 1.88 PairwiseAligner with the same scoring on 26 alignments of library parts to other NCBI records: identity and coverage within 0.1 percentage points, place, strand, call and score exact; 12 synthetic inserts on each side of every threshold; no match and 0 partial calls on 10 random sequences of 10,000 bp and both golden plasmids reversed (2026-10-06). Library 2 (2026-10-17): all 4,005 pairs of its parts aligned against each other with the same scoring, 66 of them reaching the thresholds and each published with how it is shown; no call on 12 random controls; what is shown at a locus, the parts named beside it and the inside labels exact on 14 sequences.
  • Restriction sites and cut positions. Recognition sequences and cut positions as published facts, typed by hand (pipeline/plasmid-map/enzymes.csv); every row checked against Biopython 1.88 Bio.Restriction, whose data are REBASE release 404 (Roberts RJ et al. REBASE: a database for DNA restriction and modification. Nucleic Acids Res 2023;51:D629-D630).Every row checked against Biopython 1.88 Bio.Restriction (enzyme data release 404) in its own notation, overhang and cut positions: 223 enzymes on pUC19 and pBR322, 446 cases, cut positions exact, with sites across the origin and 6 double digests (2026-10-06).
  • dam and dcm methylation of sites. McClelland M, Nelson M, Raschke E. Effect of site-specific modification on restriction endonucleases and DNA modification methyltransferases. Nucleic Acids Res 1994;22:3640-3659, Table I.Checked against 19 cases worked by hand from McClelland et al. 1994, Table I (one per outcome, flank and origin overlaps, fully methylated DpnI and host settings, plus hemi-site sensitivity entries for other enzymes; not a hemimethylated-DpnI model), and the cited blocked examples on pUC19 (MboI) and pBR322 (EcoRII), outcomes exact (2026-10-06). Which enzymes need a Table I row (82 whose site can carry a dam or dcm methylated base, 57 of them with a row) checked by a second implementation sharing no code with the engine (2026-10-17); whether Table I lists the other 25 has not been checked.
  • Sequencing-primer sites. Exact and one-mismatch matches of the shipped primers on both strands; a mismatch is reported with its distance from the primer's 3′ end and its own position, and nothing is claimed about whether such a site primes. A template letter other than A, C, G or T is an unknown base, not a mismatch: a site may hold one in place of the mismatch, and is then not exact. An oligo with more than 200 sites has none drawn or listed.Each of the 6 shipped primers found exactly at its NCBI binding site at build and every week; one-mismatch places unit-tested (2026-10-06).
  • ng, pmol, copies and ligation amounts. pmol = ng × 1000 / MW; copies = ng × 10⁻⁹ × N_A / MW, with N_A = 6.02214076 × 10²³ per mole (exact, SI 2019); insert ng = vector ng × insert bp / vector bp × ratio. MW of the double-stranded plasmid from its own sequence (both strands, no end groups when circular) with the CIAAW 2021 atomic weights.Checked against exact rational arithmetic on 11 cases (pmol, copies per µL, ng for copies, ligation, the 650 Da per bp rule and the weights of pUC19 and pBR322), to full double precision (2026-10-06).

Limits

  • For research and education only, and not medical advice: this app designs restriction, Golden Gate and Gibson products from the sequences you supply; a designed product is not evidence that the reaction occurred, and nothing here predicts whether a reaction works, how well, or whether the product is expressed.
  • Enzyme sites and cut positions are from a hand-curated table of 223 enzymes (version 1, built 2026-10-06); it may differ from a vendor's list, so check NEBcutter before a critical digest. Star activity, Type IIB and nicking enzymes are not modelled.
  • Methylation blocking is called only where McClelland et al. (1994) record it; elsewhere a site reads 'may be blocked: sensitivity not recorded', which means unknown, never 'cuts'. 25 of the 82 enzymes whose site can carry a dam or dcm methylated base have no row in this app's copy of Table I, and whether Table I lists them has not been checked.
  • Feature badges are alignment matches to public records: evidence of sequence, not of function.
  • Primer sites are exact and one-mismatch sites of the shipped primers; whether a primer primes at a mismatched site is not assessed, and a Tm is given only against a perfect match.

How these numbers were checked

Link to and cite this page

Link to this page

https://www.drybench.com/plasmid/pbluescript-sk

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Cite this page

Drybench. pBluescript II SK(+) plasmid map. Drybench Plasmid 0.19.0. https://www.drybench.com/plasmid/pbluescript-sk. Accessed [date].

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