2024/03/12 by Gregory P. Smith, Smith, Gregory P., Chenhui Zhu +7
Biochemistry, Genetics and Molecular Biology · #Advanced biosensing and bioanalysis techniques #DNA and Nucleic Acid Chemistry #FOS: Physical sciences #RNA Interference and Gene Delivery #Soft Condensed Matter (cond-mat.soft)
paper · pdf · doi:10.48550/arxiv.2403.07844
openalex publication_date 2024/03/12 · openalex created_date 2024/03/14 · openalex updated_date 2026/07/31
We report the observation of a Twist Grain Boundary (TGB) phase of DNA, a striking motif of three dimensional (3D) equilibrium self-assembly of the DNA tetramer 5'-GTAC-3', a base sequence that is self-complimentary, pairing to form 4-base long, blunt-end Watson/Crick (WC) duplexes. Hydrophobic blunt ends and liquid crystal ordering enable these short duplexes to aggregate into long-DNA-like columns, even though the double helix has a break every 4 bases. A further step assembles these columns into monolayer sheets in which the columns are mutually parallel, and, finally, these sheets stack into lamellar arrays in which the column axis of each layer rotates in helical fashion, through a 60 degree angle with each passage to the next layer. This reorientation in a left-handed TGB helix enables each 2nm diameter WC column to be parallel to, and to partially enter, the major grooves of its neighbors.