CALMING DOWN EXCITED DNA

摘要

The aromatic bases of DNA strongly absorb ultraviolet light. The energy from the UV light pushes the bases into higher energy states from which the molecule then falls to lower energy states. During this process, the molecule gives off excess energy. Researchers have long sought to understand exactly how excess energy can be dissipated without harming DNA. Now Bern Kohler and colleagues describe a falling process (DOI: 10.1021/ja4049459). The investigators make double-stranded DNA molecules with 10 pairs of A and T bases and cap either one or both ends of the DNA with a short polymer. The capping effectively constrains the bases in the DNA to adopt the ordered positions found in much longer DNA strands. Kohler and colleagues then analyze these molecules with a laser technique called deep UV femtosecond transient absorption spectroscopy.