1. What is Oligo Molar Mass?

Oligo molar mass is the molecular weight of an oligonucleotide, calculated as the sum of the molecular weights of its constituent nucleotides plus water (for terminal OH groups).

2. How Does the Calculator Work?

The calculator uses the oligo molar mass equation:

Where:

• \( MW \) — Molecular weight of the oligonucleotide (g/mol)
• \( MW_{nuc} \) — Molecular weight of each nucleotide (g/mol)

Explanation: The equation sums the molecular weights of all nucleotides in the sequence plus 18.02 g/mol for the terminal groups.

3. Importance of Molecular Weight Calculation

Details: Knowing the molecular weight is essential for preparing solutions with specific molar concentrations, which is crucial for experiments like PCR, sequencing, and hybridization.

4. Using the Calculator

Tips: Enter the oligonucleotide sequence in 5' to 3' direction using standard nucleotide codes (A, T, C, G, or U). The sequence is case-insensitive.

5. Frequently Asked Questions (FAQ)

Q1: What molecular weights are used for each nucleotide?
A: A=313.21, T=304.20, C=289.18, G=329.21, U=290.17 g/mol (as neutral, non-salt forms).

Q2: Why is water added to the calculation?
A: 18.02 g/mol is added to account for the 5' hydroxyl and 3' hydrogen terminal groups.

Q3: Does this account for modified nucleotides?
A: No, this calculator only works for standard nucleotides. Modified bases require special calculations.

Q4: How accurate is this calculation?
A: This provides theoretical average molecular weight. Actual mass may vary slightly due to isotopic distribution.

Q5: Can I calculate concentration from this?
A: Yes, using the formula: concentration (µM) = [mass (µg) × 1000] / [length × MW (g/mol)].