Friday, November 23, 2007

Self-Organizing DNA Duplexes

End-to-End Stacking and Liquid Crystal Condensation of 6– to 20–Base Pair DNA Duplexes. 2007. M. Nakata, et al. Science 318: 1276 – 1279.

DNAgents. Well, at least it has a goofy dino of the cover!
From the press release:
Reseacrhers have discovered some unexpected forms of liquid crystals of ultrashort DNA molecules immersed in water, providing a new scenario for a key step in the emergence of life on Earth.
Short segments of DNA can assemble into several distinct liquid crystal phases that self-orient parallel to one another and stack into columns when placed in a water solution. Life is widely believed to have emerged as segments of DNA- or RNA-like molecules in a prebiotic ‘soup’ solution of ancient organic molecules.

Since the formation of molecular chains as uniform as DNA by random chemistry is essentially impossible, Clark said, scientists have been seeking effective ways for simple molecules to spontaneously self-select, ‘chain-up’ and self-replicate. The new study shows that in a mixture of tiny fragments of DNA, those molecules capable of forming liquid crystals selectively condense into droplets in which conditions are favorable for them to be chemically linked into longer molecules with enhanced liquid crystal-forming tendencies, he said.

“We found this to be a remarkable result,” Clark said. “It means that small molecules with the ability to pair up the right way can seek each other out and collect together into drops that are internally self-organized to facilitate the growth of larger pairable molecules.