TE/LiAc Aqueous Solution (1.1×) is a buffer for preparing competent cells of Saccharomyces cerevisiae. TE functions as a buffer to maintain a stable pH environment; lithium acetate (LiAc) transiently renders yeast cells competent, enabling the uptake of exogenous DNA. Competent yeast cells prepared using TE/LiAc Solution (1.1×) from Aladdin exhibit a transformation efficiency of 10⁴-10⁶ cfu/μg DNA when assayed with pGADT7 plasmid.
Product Components and Formulation：
| Product Components | Molecular Formula / CAS No. | Formulation (mL/L) | Content (500 mL) | | 10× TE | C₄H₁₁NO₃/ 77-86-1
C₁₀H₁₆N₂O₈/ 60-00-4 | 110 mL | 55 mL | | 1 M LiAc | LiAc/546-89-4 | 110 mL | 55 mL | | ddH₂O | H₂O/7732-18-5 | 780 mL | 390 mL |
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Usage Protocol
I. Preparation of Competent Yeast Cells
1. Streak yeast strain on YPDA agar plate, pick a fresh single colony and inoculate into 3 mL YPDA medium in a 50 mL centrifuge tube. Incubate at 30 °C with shaking at 250 rpm for 12h. Transfer 50 μL of the overnight culture into 50 mL YPDA medium in a 250 mL Erlenmeyer flask, shake at 250 rpm until OD600 reaches approximately 0.15–0.3 (do not exceed this range).
2. Harvest cells by centrifugation at 700 g for 5 min at room temperature, discard supernatant, resuspend pellet in 100 mL YPDA medium, and shake at 30°C, 250 rpm until OD600 = 0.4–0.5.
3. Collect cells via centrifugation at 700 g for 5 min at room temperature, remove supernatant, and resuspend pellet in 50 mL sterile ddH₂O.
4. Centrifuge at 700 g for 5 min at room temperature, discard supernatant, and resuspend pellet in 15 mL pre-chilled (4°C) TE/LiAc Solution (1.1×). Centrifuge at 1500 g for 30 s and discard supernatant, then resuspend cells in 0.6 mL TE/LiAc Solution (1.1×).The competent cells can be used directly for yeast library transformation; alternatively, aliquot into 10 portions for routine yeast plasmid transformation. For optimal results, use immediately. If temporary storage is needed, keep on ice for no more than 3h.
II. Transformation Protocol for Competent Yeast Cells
Yeast Transformation Protocol – Library vs. Regular Plasmid (Comparative Table)
| Step | Parameter / Operation | Library Plasmid (Large Scale) | Regular Plasmid (Small Scale) | | 1 | Carrier DNA denaturation (common) | 95 °C water/metal bath 3 min → ice bath 3 min → repeat (95 °C 3 min) → ice bath ≥3 min | Same procedure | | 2 | Centrifuge tube size | 15‑mL tube | 1.5‑mL tube |
| Plasmid of interest | 5 – 15 μg | 0.1 – 2 μg |
| Carrier DNA | 40 μL | 5 μL |
| Yeast competent cells | 600 μL | 50 – 100 μL |
| PEG/LiAc solution | 2.5 mL | 500 μL |
| Incubation at 30 °C (water bath) | 45 min | 30 min |
| Mixing during incubation | Invert 6–8 times every 15 min | Invert 6–8 times every 10 min | | 3 | Add sterile DMSO | 160 μL | 20 μL | | 4 | Heat shock at 42 °C | 20 min | 15 min |
| Mixing during heat shock | Invert 6–8 times every 10 min | Invert 6–8 times every 7.5 min | | 5 | Discard supernatant; resuspend in 2×YPDA or YPD Plus | 3 mL | 1 mL | | 6 | Recovery shaking | 30 °C, 200 rpm, 1.5 h (common) | Same conditions | | 7 | Resuspend in 0.9% (w/v) NaCl for plating | 5 – 15 mL (for large plates) | 0.05 – 1 mL (for small plates) |
| Incubation after plating | 30 °C, 48 – 120 h (common) | Same conditions |
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Precautions
1. When preparing different quantities of competent cells, use 1.1× TE/LiAc Solution proportionally. Yeast competent cells prepared by this method cannot be stored at -80 °C.
2. Unopened 1.1× TE/LiAc Solution can be stored at 4 °C for 2 years. Discontinue use if microbial contamination is observed after opening.
3. This product is for research use only. It shall not be used for medical treatment, clinical diagnosis, food, cosmetics or other related applications. Do not store it in residential areas.
4. Our company shall not be liable for any accidents arising from improper use of this product.
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