Quantum mechanics could explain why DNA can spontaneously mutate

The process of replicating the molecule of life, DNA, is not immune to mistakes and can lead to mutations. Physicists and chemists at the University of Surrey have shown that the strange rules of the quantum world can cause errors in copying.

The two strands of the famous double helix are linked together by subatomic particles called protons and the nucleus of atoms of hydrogen. The hydrogen bonds are similar to the rungs of a twisted ladder that makes up the double helix structure discovered in 1952.

A always bonds to T and C, while G always bonds to A. Computational modeling has been able to quantify the process, which was predicted by Crick.

The team, part of the exciting new field of quantum biology, have shown that this modification in the bonds between the DNA strands is more common than previously thought. The protons can jump from one side of the barrier to the other side. If this happens just before the first step of the copying process, the error can pass through the replication machinery in the cell, leading to a mismatch and possibly a mutation.

In a paper published this week in the journal Communications Physics, the team from the Leverhulme Quantum Biology Doctoral Training Center used an approach called open quantum systems to determine the physical mechanisms that might cause the protons to jump between the DNA strands. It is thanks to a well-known yet almost magical quantum mechanism that they are able to get across.

It had been thought that quantum behavior could not occur inside a living cell. In his 1944 book "What is Life?", the Austrian physicist suggested that quantum mechanics can play a role in living systems. The latest work seems to confirm the theory.

The authors found that the local cellular environment causes the protons to be thermally activated and encouraged through the energy barrier. The protons are moving very quickly between the two strands. Some of the protons are caught on the wrong side when the DNA is cleaved.

Dr. Louie Slocombe explained that the protons in the DNA can tunnel along the hydrogen bonds in the genetic information. The modified bases can survive the DNA cleavage and replication processes.

Prof Jim Al-Khalili and Dr. Marco Sacchi supervised Dr. Slocombe's work at the Leverhulme Quantum Biology Doctoral Training Center.

Prof Al-Khalili said that the mechanism for quantum mechanical effects in DNA has been largely overlooked.

Biologists would typically expect tunneling to play a small role in low temperatures and relatively simple systems. They discount quantum effects in DNA. We believe we have proved that the assumptions do not hold.

More information: An open quantum systems approach to proton tunnelling in DNA, Communications Physics (2022). DOI: 10.1038/s42005-022-00881-8 , www.nature.com/articles/s42005-022-00881-8 Journal information: Communications Physics Citation: Quantum mechanics could explain why DNA can spontaneously mutate (2022, May 5) retrieved 5 May 2022 from https://phys.org/news/2022-05-quantum-mechanics-dna-spontaneously-mutate.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.