Useful Calculations
Nucleic Acid Data:
1 pmole of 1,000 b RNA = 0.33 µg
1 pmole of 1,000 bp DNA = 0.66 µg (3.03 pmoles of ends)
1 pmole of pUC18/19 DNA (2,686 bp) = 1.77 µg
1 pmole of lambda DNA (48,502 bp) = 32.01 µg
Molecular Weight Conversions:
MW of a double-stranded DNA molecule = (# of base-pairs) x (650 daltons/base-pair)
MW of a single-stranded DNA molecule = (# of bases) x (330 daltons/base)
MW of a single-stranded RNA molecule = (# of bases) x (340 daltons/base)
Estimating Tm of an Oligonucleotide:
Tm = [4°C x # of Cs and Gs in the oligo] + [2°C x # of As and Ts in the oligo]
Estimating Molar Amounts of Primer:
To estimate the weight of 1 picomole of oligodeoxynucleotide, multiply the number of nucleotides by 0.33 ng. For example, one picomole of a 24-mer is 7.92 ng (24 x 0.33 ng = 7.92 ng).
Estimating Molar Amounts of Template:
To estimate the weight of 100 fmoles of double-stranded DNA template, multiply the number of kilobases by 66 ng. For example, 100 fmoles of a 2.7 Kb plasmid is 178 ng (2.7 x 66 ng = 178 ng).
| Approximate Amount of Template (in nanograms) Required for DNA Sequencing Reactions | |||||
| Template Size (insert + vector) in Kilobases | |||||
| Template Required (fmoles) | 1 Kb | 3 Kb | 5 Kb | 7 Kb | 9 Kb |
| 25 | 17 ng | 50 | 83 | 120 | 150 |
| 50 | 33 | 100 | 165 | 230 | 300 |
| 75 | 50 | 150 | 250 | 350 | 450 |
| 100 | 66 | 200 | 330 | 460 | 600 |
| 150 | 100 | 300 | 500 | 700 | 900 |
| 200 | 135 | 400 | 660 | 930 | 1200 |
| 250 | 165 | 500 | 830 | 1200 | 1550 |
| 300 | 200 | 600 | 1000 | 1400 | 1800 |
Protein Yield Information
| Bacterial Cells: Escherichia coli or Salmonella typhimurium | ||
| Cell Data | per cell | per liter at 109 cells per ml |
| Wet Weight | 9.5 x 10-13 g | 0.95 g |
| Dry Weight | 2.8 x 10-13 g | 0.28 g |
| Total Protein | 1.55 x 10-13 g | 0.15 g |
| Volume | 1.15 µm3 = 1 femtoliter | |
| Protein concentration in the cell: 135 mg/ml | ||
| Theoretical maximum yield for a protein of interest from 1 liter of culture (109 cells/ml) | |
| 0.1% of total protein | 150 µg/liter |
| 2.0% of total protein | 3 mg/liter |
| 50.0% of total protein | 75 mg/liter |
Buffer and Gel Tables
| Effective Range of Separation of DNAs in Polyacrylamide Gels | |||
| Acrylamide (% [w/v])a | Effective range of separation (bp) | Xylene cyanol FFb | Bromophenol blueb |
| 3.5 | 1,000 – 2,000 | 460 | 100 |
| 5.0 | 80 – 500 | 260 | 65 |
| 8.0 | 60 – 400 | 160 | 45 |
| 12.0 | 40 – 200 | 70 | 20 |
| 15.0 | 25 – 150 | 60 | 15 |
| 20.0 | 6 – 100 | 45 | 12 |
| aN,N’-methylenebisacrylamide is included at 1/30th the concentration of acrylamide. bThe numbers given are the approximate sizes (in nucleotide pairs) of fragments of double-stranded DNA with which the dye comigrates. |
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| Separation of DNA in Denaturing Polyacrylamide (7 M Urea) Gels | |||
| % Polyacrylamide/ urea gel |
Size of band (nucleotides) | Xylene cyanol FFb (nucleotides) | Bromophenol bluea (nucleotides) |
| 4 | >250 | 155 | 30 |
| 6 | 60 – 250 | 110 | 25 |
| 8 | 40 – 120 | 75 | 20 |
| 10 | 20 – 60 | 55 | 10 |
| aThe numbers given are the approximate sizes (in nucleotide pairs) of fragments of double-stranded DNA with which the dye comigrates. | |||
| Agarose Gel Resolution Optimum Resolution for Linear DNA | |
| % Gel | Size of Fragments in Nucleotides (bp) |
| 0.6 | 1,000 – 20,000 |
| 0.7 | 800 – 10,000 |
| 0.9 | 500 – 7,000 |
| 1/2 | 400 – 6,000 |
| 1.5 | 200 – 3,000 |
| 2.0 | 100 – 2,000 |
| Acrylamide Gel Resolution of Proteins | |
| Recommended % Acrylamide | Protein Size Range |
| 8% | 40 – 200 kDa |
| 10% | 21 – 100 kDa |
| 12% | 10 – 70 kDa |