AAT Bioquest

What is the mechanism of MgCl2 during PCR amplification?

Posted May 20, 2023


MgClis an essential cofactor that boosts the performance of Taq DNA polymerase in PCR, thereby increasing the rate of DNA amplification.  It also enhances the amplification efficiency of the reaction. 

MgClalso boosts PCR efficiency by increasing the melting temperature of the reaction. The melting temperature refers to the temperature required to half denature a DNA template. 

Another significant way that MgCl2 enhances DNA activity in PCR is by facilitating effective and accurate template primer binding. This is due to the Mg2+ ions binding to the negatively charged alpha-phosphate of a dNTP and removing the remaining two phosphates, thereby decreasing the electrostatic repulsion between DNA strands. This prevents renaturation of the DNA and stabilizes the single-stranded template DNA. 

Additional resources

The Role of MgCl2 as a Lewis Base in ROMgCl-MgCl2 Electrolytes for Magnesium-Ion Batteries

Polymerase Chain Reaction (PCR)

Helixyte™ Green *20X Aqueous PCR Solution*