Poster abstracts

Poster number 26 submitted by Haiyun Liu

Nucleic Acid Protective and Rescuing Properties of Early Earth Coacervates

Haiyun Liu (Department of Biochemistry and Molecular Biology, Pennsylvania State University, , University Park, PA 16802), Christine D. Keating (Department of Chemistry, Pennsylvania State University, University Park, PA 16802), Philip C. Bevilacqua (Department of Chemistry, Pennsylvania State University, University Park, PA 16802)

It is known that RNA, as one form of genetic information carrier, can also act as catalyst, which makes it important in the emergence of life. In addition, DNA is also known to catalyze chemical reactions. Therefore, both nucleic acids could be vital molecules in prebiotic evolution.
However, it was not easy for nucleic acids to maintain their catalytic activities and keep their genetic information while evolving toward the first cell. The early Earth surface was under strong UV radiation and rich in reactive chemicals, therefore nucleic acids were facing UV and chemical damage; also, proofreading systems were less likely to exist for the earliest RNA or DNA replicase. All these factors make it challenging for nucleic acids to maintain their function and information. We propose that coacervates, which are a plausible form of encapsulation of the earliest cell, protected and rescued the nucleic acids from the damages and mutations. To test this hypothesis, we are artificially damaging nucleic acids with UV, high pH, as well as introducing mutations and modifications, and attempting to rescue them with coacervates.
Here I present results in damaging the 10-23 DNAzyme and some variants of the DNAzyme with 254 nm UV and broad-band UV light and rescuing them with Asp10 - PDAC53 coacervates. Variants with more Ts showed more sensitivity to UV damage; concentrations of the DNAzyme had different effects on the sensitivity to UV damage in different ion conditions. Coacervates were able to improve the catalytic activity of both damage and undamaged DNAzymes, however there was not a significant difference on the magnitude of the improvement.

Keywords: Complex coacervates, early Earth, UV damage