Can we live longer? Is the answer in physics?

With the help of physics and tiny magnets, researchers have discovered a new structure for telomeric DNA.

Physics is not the first scientific discipline that comes to mind when DNA is mentioned, but a group of scientists, including John Van Nort from Leiden Institute of Physics (LION) They discovered a new structure of telomeric DNA.

longevity. Technology: In every cell of our bodies there are chromosomes that carry the genes that determine our characteristics. At the ends of these chromosomes are telomeres that protect genes from damage. A bit like opal, telomeres are the plastic tips on the end of a shoelace – they protect DNA from damage and damage. However, every time a cell divides, the telomeres get shorter, even at the end Hayflick limit Upon reaching the cell, the cell can no longer divide and apoptosis occurs – programmed cell death.

This means that telomeres are sometimes seen as the key to living longer, and the researchers behind this new discovery hope it will help us better understand aging and age-related diseases.

As a biophysicist, Van Noort uses methods from physics for biological experiments; His work attracted the attention of biologists from Nanyan Technological University in Singapore, who asked him to help study the DNA structure of telomeres. The results of their collaboration were published in temper nature.

bead chain

The chromosomes may be microscopic, but the length of DNA between telomeres is two metres! This means that they must be neatly packaged and folded to fit into the cell, and this is accomplished by wrapping DNA around bundles of proteins; Together, DNA and proteins are called a nucleosome, and they are arranged into something somewhat like a string of beads, with a nucleosome, a piece of (or unbound) DNA, a nucleosome, and so on.

Read more: Is aging a biological problem or a physical issue? Our Interview with Dr. Leonard Hayflick

This string of beads flexes more, but how to do this depends on the length of the DNA between nucleosomes, the granules on the strand. The two structures that occurred after folding were already known—in one, two adjacent beads stick together and free DNA dangles between them (Fig. 2a). If the piece of DNA between the beads is shorter, the adjacent beads will not be able to stick to each other. Then two sets of stacks form side by side (Fig. 2b).

The three different structures of DNA
The three different structures of DNA | Photography: Finn Leiflang, Leiden University

Van Noort and colleagues found in their study another telomere structure – here the nucleosomes are much closer together, so there is no longer any free DNA between the beads; This eventually creates a single large helix, or helix, of DNA (Fig. 2C) [1].

natural magnetism

The new structure was discovered with a combination of electron microscopy and molecular force spectroscopy, with the latter technique originating in Van Noort’s laboratory. In molecular force spectroscopy, one end of the DNA is attached to a glass slide and a small magnetic ball is affixed to the other end – a group of powerful magnets on top of this ball and then separating the string of pearls.

By measuring how much force is needed to separate the beads one by one, it is possible to discover more about how the thread folds, and as a follow-up, the researchers in Singapore used an electron microscope to get a better picture of the structure.

building blocks

Van Noort describes synthesis as “the holy grail of molecular biology”. He shows that if we knew the structure of molecules, this would give us more insight into how genes are turned on and off and how enzymes in cells deal with telomeres – how they repair and copy DNA, for example [2].

Researchers feel that discovering the new telomere structure will improve understanding of the body’s basic building blocks, which in turn will eventually help in the study of aging and age-related diseases such as cancer — and aid in developing drugs to fight them. .

[1] https://www.nature.com/articles/s41586-022-05236-5
[2]

Can we live longer?  Is the answer in physics?