DNA damage caused by migrating light energy
UV radiation modifies DNA also far away from the entry point of light


Date:
September 14, 2020
Source:
Karlsruher Institut fu"r Technologie (KIT)
Summary:
Ultraviolet light endangers the integrity of human genetic
information and may cause skin cancer. For the first time,
researchers have demonstrated that DNA damage may also occur far
away from the point of incidence of the radiation. They produced an
artificially modeled DNA sequence in new architecture and detected
DNA damage at a distance of 30 DNA building blocks.



FULL STORY ========================================================================== Ultraviolet light endangers the integrity of human genetic information
and may cause skin cancer. For the first time, researchers of Karlsruhe Institute of Technology (KIT) have demonstrated that DNA damage may
also occur far away from the point of incidence of the radiation. They
produced an artificially modeled DNA sequence in new architecture and
succeeded in detecting DNA damage at a distance of 30 DNA building blocks.


==========================================================================
"So far, we have thought that it is impossible for light energy
to be transmitted so far in the DNA and cause damage there," says
Professor Dr. Hans- Achim Wagenknecht from KIT's Institute of Organic Chemistry. The research results are presented in Angewandte Chemie and
are ranked as extraordinarily important and in the best ten percent
by the journal. For the study, a synthetically produced, modified DNA
of a certain architecture was used. At certain points of this short
gene section, researchers inserted a xanthone molecule as photoenergy
injector. To specify where the UV radiation produced by LEDs was to cause damage in the experiment, scientists inserted pairs of thymines at defined distances from this light injector. Thymine is one of four nucleobases
and, hence, one of the major building blocks of DNA. The most frequent
damage of DNA caused by light results from linking neighboring thymines:
Due to the light energy, they form solid compounds of cyclobutane
pyrimidine dimers (CPD).

Having defined the positions of CPD formation, the team succeeded in
proving migration of photoenergy over 30 DNA building blocks corresponding
to a distance of up to 10.5 nanometers. "This surprisingly long range is crucial to the understanding of DNA photodamage," Wagenknecht says. CPD
damage is considered the molecular cause of skin cancer, because genetic information can no longer be read or cannot be read correctly.

The question of how far energy can migrate is still open. Above all,
the scientists wanted to find out where photodamage develops. Another
important aspect is that xanthones artificially introduced into the DNA
as light injectors may be contained in many common substances, such as antibiotics, and may increase light sensitivity of the skin after intake.


========================================================================== Story Source: Materials provided by
Karlsruher_Institut_fu"r_Technologie_(KIT). Note: Content may be edited
for style and length.


========================================================================== Journal Reference:
1. Arthur Kuhlmann, Larissa Bihr, Hans‐Achim Wagenknecht. How
Far Does
Energy Migrate in DNA and Cause Damage? Evidence for
Long‐Range Photodamage to DNA. Angewandte Chemie International
Edition, 2020; DOI: 10.1002/anie.202009216 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/09/200914112216.htm

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