Stretching DNA to the Limit

http://www.bionity.com/news/e/63986/?ps=&pw=a&t=&defop=and&wild=yes&sdate=01/01/1995&edate=04/26/2007&sort=1

Researchers at Duke University have used single-molecule force spectroscopy to measure the forces generated by the unraveling of DNA strands exposed to UV light. Although we already knew that UV light can damage DNA molecules, this technique is allowing the team of researchers to analyze the changing mechanical properties as the damage occurs.

The change in structure is due largely to the encouraging of crosslinkingof bases within the polynucleotide chains. This has been shown to cause unwinding of the double helix in certain regions where the amount of crosslinking is considerable. Small changes such as this affect the DNA's capability of working properly during transcription. This leads to the inability to produce the correct proteins.

As discussed in our biomechanics class, biology and mechanical changes at a molecular level affect each other in profound ways. The body responds to a stimulus like UV light at the DNA level and these changes are apparent at the gross level with things like skin cancer,which is a result of prolonged UV exposure.