Magnesium helps to create, repair and protect DNA and proteins
For those who need a brief refresher, DNA, or deoxyribonucleic acid, is a long, twisting double-stranded molecule found in the nucleus of every cell. These nucleic acids contain the sum of genetic information that makes us unique organisms. They’re also the blueprints for making all proteins in the body.
DNA strands are made of sequences of nucleotide bases: adenine, thymine, cytosine and guanine. Because of the way these nucleotides are attracted to one another, the opposite strand in a DNA molecule will have a mirror sequence of nucleotide bases. Adenine is always paired across thymine, and cytosine is always paired across guanine. These base pairs look something like this:
Magnesium is involved in the following DNA functions.
Making proteins
When a protein needs to be created, specific DNA nucleotide sequences are read and copied (transcribed) onto another molecule called RNA. The RNA strand is then moved out of the nucleus where enzyme-like organelles called ribosomes use it as a guide to synthesize chains of amino acids that form the desired protein.
This protein synthesis relies on all sorts of enzymes to work, from helicases that open up the DNA strand to be read, to RNA polymerases that create RNA-based on the original DNA sequence, to protein kinases. Magnesium is a cofactor for most of these critical enzymes. The ribosome, while not technically an enzyme, is the most important catalyst for stitching together amino acids into proteins. Lots of magnesium is needed to keep this complex ribo protein stable.
Without enough magnesium, protein synthesis is impaired. And since protein is used for most of the structural components and nearly all metabolic functions in the body, a lack of proteins can have widespread consequences.
Creating DNA
We mentioned earlier that magnesium is an essential cofactor for an enzyme called DNA polymerase which repairs and replicates strands of DNA using spare nucleotides floating around in the nucleus.
After other enzymes “unzip” the double-strands of DNA, DNA polymerases attach to each strand and begin to travel down the sequence of nucleotides. As it travels, the magnesium ions bound to the enzyme help open up the nucleotide site, drawing the new, free nucleotide into position.
DNA polymerase is used all the time in DNA repair and DNA copying, creating new strands at a speedy rate of 3,000 nucleotides per minute. Consider the magnitude of the role this enzyme plays. Hundreds of billions of cell divisions occur in the body daily, and each time a cell divides, it needs to replicate an identical set of DNA, or approximately 3 billion base pairs.
DNA polymerase has two binding sites for magnesium. Without magnesium, it cannot work. This is corroborated by studies that show DNA synthesis visibly slowing in the absence of enough magnesium.
Repairing DNA
DNA polymerase is a very accurate enzyme, making less than one mistake in a billion base pairs. But even if DNA is copied perfectly, mistakes in the DNA sequences do occur. Genetic damage can occur because of thermal changes, radiation, viruses or the presence of highly reactive chemicals. There’s a lot that can go wrong when you’re maintaining 3 billion base pairs. If left unchecked, these mutations will be propagated with every cell division.
There is a whole other set of processes dedicated to identifying and correcting damaged DNA. The involved enzymes cut away the damaged sections and repair the gap with fresh nucleotides. Unsurprisingly, magnesium is involved in almost every enzyme in this process.
Protecting nucleotide bindings and proteins
Magnesium also has a stability effect on the structures of proteins and DNA. You might remember that for electrical charge, opposites attract and likes repel. No? Try rubbing two balloons against your hair. Now put them side by side. Because you’ve given them the same electrostatic charge, they will push apart. DNA is like that too.
Each strand in a DNA double-helix is negatively charged. Without the hydrogen bonds of their nucleotide base pairs holding them together, they will repel and break apart. In situations where DNA is exposed to higher temperatures or extreme pH, these hydrogen bonds can break. Magnesium ions have a strong positive charge.
Concentrated in the nucleus of cells, these ions can help reduce the negative charges in the DNA strands, stabilizing their structure.
This effect has been tested experimentally – a higher concentration of magnesium will measurably raise the melting temperature of DNA molecules.Many proteins and protein complexes incorporate magnesium into their structure – about 3751 human proteins with magnesium binding sites to date.
