Plasmid Product Nomenclature

The SnapFast system is a versatile plasmid cloning platform that provides a range of functional DNA sequences in an easy to clone format. We currently have hundreds of pre-designed DNA sections that can be easily incorporated into, or transferred between, our range of plasmids. This page contains a brief explanation of the nomenclature used in the system, to allow you to determine what is in each plasmid by using its name. 

Component nomenclature

All of the plasmids in the system are named to reflect the DNA sections that they contain.

Backbone: All inserts are sold in the same plasmid backbone, called pSF-Core. This is the first piece of information in the name.

Promoter: The second piece of information in any plasmid name is always the promoter, for example pSF-SV40 contains the SV40 promoter.  

N-terminal tags: If a coding sequence (a peptide tag for example) has been designed to be fused to the 5’ end of a gene it will be labelled as' NH2' to reflect which end of the translated protein it will be fused to. For example, pSF-CMV-NH2-His-EKT1 has the CMV promoter driving the coding sequence for a Histidine affinity tag (His) upstream of an enterokinase (EKT) protease cleavage tag followed by the MCS.

C-terminal tags: If a coding sequence (a peptide tag for example) has been designed to be fused to the 3’ end of a gene it will be labelled as 'COOH' to reflect which end of the translated protein it will be fused to. For example, pSF-CMV-COOH-EKT-His contains the CMV promoter followed by the multiple cloning site and then the enterokinase (EKT) protease cleavage tag coding sequence, followed by the coding sequence for a histidine affinity tag (His).

Frames and Fusions: Any plasmids that have the suffix 1, 2 or 3 refers to the frame of any coding sequence that has been inserted into the plasmid, and provides a reference point from which to pick your desired plasmid.

Product Terminology

NH2 - N-terminal tag, to be inserted upstream of the main MCS, and fused to the N-terminus of your expressed protein.

COOH - C-terminal tag, to be inserted downstream of the main MCS, and fused to the C-terminus of your expressed protein.

SP -
Secretory signal peptide.

EKT -
An enterokinase cleavage tag , used to cleave off a tag from a purified protein, with the amino acid sequence DDDDK (found in a FLAG tag).

V5 -
An Epitope string with the amino acid sequence GKPIPNPLLGLDST.

C-Myc - An Epitope string with the amino acid sequence EQKLISEEDL.

FLAG -
An Epitope string with the amino acid sequence DYKDDDDK.

HA - An epitope tag from influenza virus with the amino acid sequence YPYDVPDYA.

GST -
A peptide tag that encodes Glutathione-S-transferase and binds to Glutathione.

MBP -
A peptide tag that encodes Maltose binding protein and binds to maltose.

HIS -
A peptide tag that encodes a string of histidine residues and binds nickel.

P2A - a auto-catalytic protease peptide that cuts within itself to GSGATNFSLLKQAGDVEENPGP. Cleavage occurs between the penultimate glycine and the final proline.

IRES -
Internal ribosome binding site, usually from either encephalomyocarditis virus (EMCV) or Foot and Mouth Disease Virus (FMDV).

MCS -
Multiple cloning site or polylinker

IRES PciI -
An IRES in which a PciI site (ACATGT, start codon in bold) has been positioned in the correct place to enable protein translation. For reference, NcoI, PciI, BspHI all have compatible cohesive ends after digestion.

NH2 1,2 or 3 -
When used in a product name, these refer to the reading frame of the coding sequence in question. All NH2 coding sequences (N-terminal protein tags) that are labelled 1 are in frame with the start codon in the NcoI site. All those labelled 2 are one base out of frame, and all those labelled 3 are two bases out of frame with this same codon.

COOH 1, 2, or 3 -
When used in a product name, these refer to the reading frame of the coding sequence in question. All COOH coding sequences (C-terminal protein tags) that are labelled 1 are in frame with the stop codon in the XbaI site (that is ablated in all vectors containing a C-terminal fusion sequence). All those labelled 2 are one base out of frame, and all those labelled 3 are two bases out of frame with this same codon.