Nucleic acid transport through carbon nanotube membranes.
We study the electrophoretic transport of single-stranded RNA molecules through 1.5-nm-wide pores of carbon nanotube membranes by molecular dynamics simulations. From approximately 170 individual RNA translocation events analyzed at full atomic resolution of solvent, membrane, and RNA, we identify key factors in membrane transport of biopolymers. RNA entry into the nanotube pores is controlled by conformational dynamics, and exit by hydrophobic attachment of RNA bases to the pores. Without electric field, RNA remains hydrophobically trapped in the membrane despite large entropic and energetic penalties for confining charged polymers inside nonpolar pores. Differences in RNA conformational flexibility and hydrophobicity result in sequence-dependent rates of translocation, a prerequisite for nanoscale separation devices.
Laboratory of Chemical Physics, Building 5, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520, USA.
In-Chul
IC
Yeh
Gerhard
G
Hummer
D001693:Biological Transport, Active; D004058:Diffusion; D004563:Electrochemistry; D066298:In Vitro Techniques; D007700:Kinetics; D008567:Membranes, Artificial; D008958:Models, Molecular; D037742:Nanotubes, Carbon / Q000737:chemistry*; D009690:Nucleic Acid Conformation; D012313:RNA / Q000737:chemistry / Q000378:metabolism*; D013816:Thermodynamics
D008567:Membranes, Artificial; D037742:Nanotubes, Carbon; D012313:RNA