SCIENTISTS IN Fife probing an ancient microbe have shed new light on a rare condition that causes acute sensitivity to the sun, and they are hoping for better understanding of a rare genetic disease that carries an exceptionally high cancer risk.

The researchers at St Andrews University investigated the microbe—found in hot volcanic pools—for clues relevant to human disease and cancer.

They are now said to have offered “remarkable insights” into the puzzling question of why some gene mutations cause cancer whilst others lead to premature ageing.

The St Andrews team is led by Professors Malcolm White and James Naismith at the university’s Centre for Biomolecular Sciences (CBMS), who hope that the study may lead to better understanding of the debilitating genetic condition XP (xeroderma pigmentosum).

Sufferers of the XP condition cannot be exposed to normal sunlight.

Professor White said that XP and other diseases are caused by mutations in the XPD protein, a crucial DNA repair enzyme that normally protects us against the damaging effects of UV radiation in sunlight.

The St Andrews breakthrough lies in the solving of the molecular structure of the XPD protein, which will help researchers understand the mechanisms behind such mutations.

At the heart of the discovery is the use of the ancient microbe, which makes an excellent model for the human protein since its structure has been conserved through three billion years of evolution.

Professor White said a combination of structural and molecular biology has allowed the team to probe this fascinating enzyme.

“This ancient lineage of microbes has interesting similarities to humans, in the way in which they process information,” he said.

“This includes DNA replication, transcription and repair. The structures are often very close matches to the equivalent proteins from humans, even though they diverged from one another three billion years ago.

“Thanks to this discovery we can now appreciate why some mutations cause cancer whilst others lead to premature ageing.”

The work was funded by Cancer Research UK, the Biotechnology and Biological Sciences Research Council, the Scottish Funding Council and St Andrews University, and builds on previous work funded by the St Andrews-based charity Association for International Cancer Research.

Professor Naismith said, “The discovery will help in our understanding of the basic principles behind DNA repair and genetic conditions such as XP.

“It is possible that this information will aid in the development of new anti-cancer drugs in the future, although that is likely to be many years away.”