Conversion of a Ribozyme to a Deoxyribozyme through In Vitro Evolution

[logical muse]

From the abstract:

An RNA ligase ribozyme was converted to a corresponding deoxyribozyme through in vitro evolution. The ribozyme was prepared as a DNA molecule of the same sequence, and had no detectable activity. A population of randomized variants of this DNA was constructed and evolved to perform RNA ligation at a rate similar to that of the starting ribozyme. When the deoxyribozyme was prepared as an RNA molecule of the same sequence, it had no detectable activity. Thus, the evolutionary transition from an RNA to a DNA enzyme represents a switch, rather than a broadening, of the chemical basis for catalytic function. This transfer of both information and function is relevant to the transition between two different genetic systems based on nucleic acid-like molecules, as postulated to have occurred during the early history of life on Earth.

The paper is here:
http://www.chembiol.com/content/article/fulltext?uid=PIIS1074552106000421

My understanding of this is that they evolved the RNA enzyme into a DNA enzyme, a significant result. I'm no expert though, and couldn't really follow all the details of the paper.

 

[Soapy Sam]

"...there is no known example of a deoxyribozyme in nature..."

Which sounds like a jolly good reason not to go creating any.


The paper does not actually make clear what's meant by "in vitro evolution". Got any info on what this entails?

 

[El Greco]

I think the point is that they speculate it was possible for RNA to convert to DNA without biological activity. Since RNA preceded DNA, they propose a strictly "chemical" way of DNA's appearance.