Ever wonder why we humans have to wear sunscreen while so many other forms of life basically just live unhindered in direct sunlight? Trees and plants, who are as much alive as we are and have DNA just like we do, spend their entire life under a barrage of photons from the sun. Reptiles, bacteria, fungi, insects etc. are also remarkably protected from sun. Why don’t they suffer sun damage like we do?
The answer, it turns out, lies in our variations of DNA. Unlike most other, older forms of life on earth, many mammals, including humans, traded their most advanced sun protection mechanisms for some other evolutionary trait.
In short: most plants and animals on earth contain an incredibly advanced DNA-protecting enzyme called photolyase. Due to genetics, this enzyme is now missing in humans and several other species of mammals – that’s why we are more susceptible to sun damage, why the sun ages our skins so quickly and why we are so prone to skin cancer.
Science discovers how photolyase works
In 2010, scientists observed for the first time how the key enzyme actually works at an atomic level. And it has completely changed how we think about sun damage and photo-repair.
Remember our recent article “Invisible enemies”, where we explain that sunlight and oxygen literally break/damage your DNA, causing accelerated skin ageing? Well, in broad terms, photolyase actually uses UV light to heal unfixable DNA breaks. But, to fully understand how much more advanced it is than our inherent DNA repair mechanisms, we have to take a quick look at the types of DNA damage our skin encounters.
Types of DNA damage in the skin
Sunlight and oxygen directly and indirectly damage the DNA inside the cells of your skin. Normally, your body is quite good at healing some types of DNA damage, using the Nucleotide Excision Repair (NER) mechanism (most mammals traded photolyase for NER millions of years ago). But NER can’t heal all types of damage. And that’s the root of humans’ sun damage problems.
NER fixable DNA damage
Unfixable DNA damage
Our bodies’ NER can repair most basic types of DNA damage, but not the dreaded thymine dimer. Basically, what happens here is that UV light damages two bases (the steps in the DNA strand), and they get stuck together.
A dimer like this is devastating to your body. Your cell can’t read the DNA properly, and the best-case scenario is that the cell can’t function and just dies. The worst-case scenario is that it mutates and becomes skin cancer, infecting all other cells around it.
Photolyase can fix dimers
This brings us back to photolyase, and you can probably already see why it is considered a potential miracle for fighting sun damage. Photolyase is specifically designed by nature to fix thymine dimers.
The photolyase enzyme physically travels along a DNA strand, detects a DNA dimer and produces a healing electron and proton that force their way in between the dimer’s two fused DNA bases, reversing the polarity and repairing the dimer within minutes of application.
Photolyase is so advanced at healing previously unfixable DNA damage, that it is currently being studied as a potential component in the fight against cancer.
Photolyase is now available in Lamelle’s Helase!
In case you missed it, Lamelle Research Laboratories recently launched the all-new Helase photo-repair cream. This is currently the only product in South Africa that offers the remarkable DNA-healing properties of photolyase.
Ask your skin therapist about Helase, she’ll know.
Got a skin sun damage, DNA or photolyase question? Ask away in the comments below.