Dna Oligo Molecular Weight Calculator

DNA Oligo Molecular Weight Formula:

\[ MW = (number\ of\ bases \times 330) - (number\ of\ bonds \times 18) \]

Molecular Weight (MW):

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1. What is DNA Oligo Molecular Weight?

Molecular weight of a DNA oligonucleotide is the sum of the atomic weights of all atoms in the molecule. It's an important parameter for various molecular biology applications including PCR, sequencing, and hybridization experiments.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ MW = (number\ of\ bases \times 330) - (number\ of\ bonds \times 18) \]

Where:

\( number\ of\ bases \) — Total nucleotide bases in the oligo
\( 330 \) — Average molecular weight per base (g/mol)
\( number\ of\ bonds \) — Number of phosphodiester bonds
\( 18 \) — Molecular weight of water (g/mol)

Explanation: The formula accounts for the mass of individual nucleotides while subtracting the mass of water molecules lost during bond formation.

3. Importance of Molecular Weight Calculation

Details: Accurate molecular weight calculation is crucial for determining oligo concentration, designing experiments, calculating melting temperatures, and preparing solutions with precise molar concentrations.

4. Using the Calculator

Tips: Enter the number of bases in your oligonucleotide and the number of phosphodiester bonds. For a typical single-stranded DNA oligo, the number of bonds is usually (number of bases - 1).

5. Frequently Asked Questions (FAQ)

Q1: Why subtract water mass for each bond?
A: During phosphodiester bond formation, a water molecule is removed (dehydration synthesis), so we subtract its molecular weight.

Q2: Is 330 g/mol accurate for all bases?
A: 330 g/mol is an average value. Actual base weights vary: A=313.2, T=304.2, C=289.2, G=329.2 g/mol, but 330 provides a good approximation.

Q3: How do I calculate number of bonds?
A: For a linear single-stranded DNA oligo, number of bonds = number of bases - 1. For other structures, adjust accordingly.

Q4: Does this work for modified oligos?
A: No, this calculator is for standard DNA bases. Modified bases with different molecular weights require specialized calculation.

Q5: What about double-stranded DNA?
A: For double-stranded DNA, calculate each strand separately and add the results, or use specialized calculators that account for duplex formation.