pTrc99a
pTrc99a is a pTrc-series protein expression plasmid of Escherichia coli. It places the gene of interest under the hybrid trc/lac promoter for tight, IPTG-inducible expression, carries the pBR322 high-copy origin and ampicillin resistance, and is widely used for recombinant protein production in E. coli. Suitable for general cloning and heterologous gene expression.
Q: How should I reconstitute the lyophilized plasmid?
A: Centrifuge the tube at 5000 rpm/min for 1 minute to collect the powder, then add 20 ul of sterile ddH2O (or TE buffer) and mix gently. For transformation, typical usage is 2 ul plasmid into 100 ul competent cells.
Q: What are the shipping and storage conditions?
A: Plasmids are shipped at 2-8 C (refrigerated). Upon receipt, store the lyophilized plasmid at -20 C for long-term stability. Avoid repeated freeze-thaw cycles.
Q: How do I select for transformants?
A: Use the antibiotic resistance carried by the vector (ampicillin, chloramphenicol, kanamycin, etc.) in your selection medium. Some vectors also provide a secondary screening marker (e.g., tetracycline, spectinomycin, G418/Neo, Hyg).
Q: Which competent cells should I use?
A: Most E. coli vectors are propagated in DH5 alpha or similar cloning strains. Note that some vectors (e.g., pGWB4 carrying ccdB) require a ccdB-resistant strain such as DB3.1. Always match the strain to the vector requirements.
Q: Are sequencing primers provided?
A: Sequencing primers are listed in each product's specifications where available (e.g., pTrc99a, pEGFP-C2). For vectors without listed primers, standard vector primers (M13, T3, T7, SK) or sequence-derived primers can be used.
Q: Are these plasmids for diagnostic or therapeutic use?
A: No. All plasmids are FOR RESEARCH USE ONLY and are not intended for diagnostic, therapeutic, or human/animal consumption purposes.
Q: Can I obtain the full vector map and sequence?
A: Yes. The full nucleotide sequence is provided in the downloadable specification manual (PDF) and on the product page. The official annotated vector map is available from LSMBIO on request.
Q: What is the supplied amount?
A: Each plasmid is supplied as 2 ug of lyophilized DNA, sufficient for multiple transformations, subcloning, or transfection experiments.
