The Effects Of Cations On The Dynamics Of Single Stranded DNA

Narae Lee

School Name

Governor's School for Science and Math

Grade Level

12th Grade

Presentation Topic

Physics

Presentation Type

Mentored

Mentor

Mentor: Dr. Jeong; Department of Physics, Korean Advanced Institute for Science and Technology

Abstract

The nucleic acids, RNA and DNA, perform several important functions within cells in coding, decoding, regulation, and expression of genes. The physical properties of nucleic acids, including their size and electronegativity, contribute to their varying patterns of folding and dynamics in dissimilar conditions. Our research was conducted using fluorescent correlation spectroscopy to observe how cation concentration and type changes the flexibility of single-stranded DNA, measured by calculating persistence length. Varying cation type resulted in a difference in the concentration at which the persistence length transitioned from high to low. The experiment found that the divalent cations Mg2+ and Ca2+ transitioned at a much lower concentration than the monovalent cation K+ did. Between the divalent cations, Mg2+ appeared to transition at a slightly lower concentration than Ca2+, but the difference was much smaller. The observations led to the claims that charge is a major factor in the transition between persistence lengths, while ionic radius may be only a minor factor. The latter claim would need to be confirmed or disproved by further experiments as the data for the divalent cations was less accurate. The research helps to deepen the understanding of folding behavior and dynamics of single stranded nucleic acids in vivo.

Location

Owens 104

Start Date

4-16-2016 9:00 AM

COinS
 
Apr 16th, 9:00 AM

The Effects Of Cations On The Dynamics Of Single Stranded DNA

Owens 104

The nucleic acids, RNA and DNA, perform several important functions within cells in coding, decoding, regulation, and expression of genes. The physical properties of nucleic acids, including their size and electronegativity, contribute to their varying patterns of folding and dynamics in dissimilar conditions. Our research was conducted using fluorescent correlation spectroscopy to observe how cation concentration and type changes the flexibility of single-stranded DNA, measured by calculating persistence length. Varying cation type resulted in a difference in the concentration at which the persistence length transitioned from high to low. The experiment found that the divalent cations Mg2+ and Ca2+ transitioned at a much lower concentration than the monovalent cation K+ did. Between the divalent cations, Mg2+ appeared to transition at a slightly lower concentration than Ca2+, but the difference was much smaller. The observations led to the claims that charge is a major factor in the transition between persistence lengths, while ionic radius may be only a minor factor. The latter claim would need to be confirmed or disproved by further experiments as the data for the divalent cations was less accurate. The research helps to deepen the understanding of folding behavior and dynamics of single stranded nucleic acids in vivo.