Toroidal DNA condensates: unraveling the fine structure and the role of nucleation in determining size.

TitleToroidal DNA condensates: unraveling the fine structure and the role of nucleation in determining size.
Publication TypeJournal Article
Year of Publication2005
AuthorsHud, NV, Vilfan, ID
JournalAnnu Rev Biophys Biomol Struct
Date Published2005
KeywordsBiophysics, Cations, Cryoelectron Microscopy, DNA, DNA, Circular, Kinetics, Microscopy, Electron, Transmission, Models, Chemical, Nucleic Acid Conformation, Plasmids, Polymers, Thermodynamics

Toroidal DNA condensates have attracted the attention of biophysicists, biochemists, and polymer physicists for more than thirty years. In the biological community, the quest to understand DNA toroid formation has been motivated by its relevance to gene packing in certain viruses and by the potential use of DNA toroids in artificial gene delivery (e.g., gene therapy). In the physical sciences, DNA toroids are appreciated as a superb model system for studying particle formation by the collapse of a semiflexible, polyelectrolyte polymer. This review focuses on experimental studies from the past few years that have significantly increased our understanding of DNA toroid structure and the mechanism of their formation. Highlights include structural studies that show the DNA strands within toroids to be packed in an ideal hexagonal lattice, and also in regions with a nonhexagonal lattice that are required by the topological constraints associated with winding DNA into a toroid. Recent studies of DNA toroid formation have also revealed that toroid size limits result from a complex interplay between kinetic and thermodynamic factors that govern both toroid nucleation and growth. The work discussed in this review indicates that it will ultimately be possible to obtain substantial control over DNA toroid dimensions.

Alternate JournalAnnu Rev Biophys Biomol Struct
PubMed ID15869392
Grant ListGM62873 / GM / NIGMS NIH HHS / United States