For scientists attempting to understand how the building blocks of RNA originated on Earth, guanine -- the G in the four-letter code of life -- has proven to be a particular challenge. While the other three bases of RNA -- adenine (A), cytosine (C) and uracil (U) -- could be created by heating a simple precursor compound in the presence of certain naturally occurring catalysts, guanine had not been observed as a product of the same reactions.
By adding ultraviolet light to a model prebiotic reaction, researchers from the Georgia Institute of Technology and the University of Roma, "La Sapienza", have discovered a route by which the missing guanine could have been formed. They also found that the RNA bases may have been easier to form than previously thought -- suggesting that starting life on Earth might not have been so difficult after all.
The findings are reported June 14, 2010 in the journal ChemBioChem. This collaborative work is supported by the National Science Foundation (NSF), the National Aeronautics and Space Administration, and the European Space Agency. The NSF funding is provided through the Center for Chemical Evolution at Georgia Tech.
Understanding how life emerged is one of the greatest scientific challenges. There is considerable evidence that the evolution of life passed through an early stage in which RNA played a more central role, before DNA and protein enzymes appeared.
Recent efforts to understand the prebiotic formation of the building blocks of RNA have focused on the chemical formamide (H2NCOH) as a potential starting material to create the RNA bases because it contains the four required elements -- carbon, hydrogen, oxygen and nitrogen -- and because of its stability, reactivity and low volatility compared to water. Previous reports have shown that these nucleic acid components -- with the exception of guanine -- can be synthesized by heating formamide to 160 degrees Celsius in the presen
|Contact: Abby Vogel Robinson|
Georgia Institute of Technology Research News