Basic Conversion of Nucleic Acids and Nucleotides

1. Conversion of nucleic acids

(1) Moles and mass

1 ug 1,000bp DNA = 1.52 pmol
1 ug SV40 DNA (5,243bp) = 0.29 pmol
1 ug FX174 DNA (5,386bp) = 0.28 pmol
1 ug lambda phage DNA (48,502bp) = 0.03 pmol
1 ug M13mp18/19 DNA (7,249bp) = 0.21 pmol
1 ug pBR322 DNA (4,361bp) = 0.35 pmol
1 ug pUC18/19 DNA (2,686bp) = 0.57 pmol
1 pmol 1,000bp DNA = 0.66 ug
1 pmol M13mp18/19 DNA (7,249bp) = 4.78 ug
1 pmol SV40 DNA (5,243bp) = 3.46 ug
1 pmol pUC18/19 DNA (2,686bp) = 1.77 ug
1 pmol pBR322 DNA (4,361bp) = 2.88 ug
1 pmol lambda phage DNA (48,502bp) = 32.01 ug
1 pmol FX174 DNA (5,386bp) = 3.55 ug

(2) Absorbance and concentration

1 OD260 dsDNA = 50 mg/ml
1 OD260 ssDNA = 33 mg/ml
1 OD260 ssRNA = 40 mg/ml

(3) Molecular weight (MW)

Average MW of dsDNA base pair = 600 Daltons
Average MW of ssDNA base pair = 333 Daltons
Average molecular weight of RNA base is 340 Daltons

(4) Concentration of nucleic acid end

Linear DNA：pmol ends = pmol DNA´ (number of cuts ´2 + 2)
Circular DNA：pmol ends = pmol DNA´ number of cuts ´2
1 ug linear 1,000bp DNA = 3.04 pmol ends
1 ug linear FX174 DNA (5,386bp) = 0.56 pmol ends
1 ug linear pUC18/19 DNA (2,686bp) = 1.14 pmol ends
1 ug linear SV40 DNA (5,243bp) = 0.58 pmol ends
1 ug linear pBR322 DNA (4,361bp) = 0.7 pmol ends
1 ug linear lambda phage DNA (48,502bp) = 0.06 pmol ends
1 ug linear M13mp18/19 DNA (7,249bp) = 0.42 pmol ends

2. Conversion of nucleotides

(1) Molecular weight (MW)

MW (Da) = 333’N (number of bases)

(2) Concentration

C (mmol/L or pmol/ml) = OD260 / (0.01´N) C (ng/ml) = OD260’ MW / (0.01´N)
Tips: OD260—absorbance at 260 nm

(3). Double-stranded DNA with a melting point of oligonucleotides：

Shorter than 20bp double-stranded oligonucleotide: Tm = 2 (A + T) + 4 (G + C)
Longer than 20bp double-stranded oligonucleotide: Tm = 81.5 + 16.6 ( lg[J+] ) + 0.41 (%GC) –(600/N)
Tips: N—Length of the primer (calculate the number of bases)；J+ —— Monovalent cation concentration

(4). Protein/DNA Conversions

1 kb DNA = 333 amino acid ≈ 3.7´104 Da
10,000 Da Protein ≈ 270 bp DNA
30,000 Da Protein ≈ 810 bp DNA
50,000 Da Protein ≈ 1350 bp DNA
100,000 Da Protein ≈ 2700 bp DNA