Spontaneous formation of liquid crystalline phases and phase transitions in highly concentrated plasmid DNA
Artikel i vetenskaplig tidskrift, 2011

The liquid crystalline (LC) properties of two supercoiled plasmid DNA samples, pBSK (2958 bp) and pGEM (3000 bp), have been studied using polarised light microscopy (PLM), circular dichroism (CD) and UV-Vis spectroscopy. The influence of methods of isolation on plasmid LC behaviour is described, and using PLM we have demonstrated the spontaneous formation of cholesteric fingerprint-like textures. Preliminary studies of LC phase transitions in pGEM show the irreversibility of LC phase formation, as a consequence of changes in the tertiary structure of supercoiled plasmids. Using UV-Vis spectroscopy a hyperchromic effect was observed with increasing temperature. The CD spectra clearly showed structural changes, and probably mismatching of DNA bases, during cooling. Finally, we have observed an irreversible phase transition in plasmid DNA which is very different from that previously reported in linear DNA.

fingerprint-like texture

escherichia-coli

supercoiling

linking

supercoiled dna

dimensions

liquid crystal

isolation techniques

shock

phase transition

growth temperature

thermal-denaturation

cholesteric phase

nucleic acids

DNA

microscopy

circular dichroism

bacteria

hyperchromic effect

plasmid DNA

Författare

Piotr Hanczyc

Chalmers, Kemi- och bioteknik, Fysikalisk kemi

K. Matczyszyn

Wrocław University of Science and Technology

K. Pawlik

Ludwik Hirszfeld Institute of Immunology and Experimental Therapy of the Polish Academy of Sciences

AKademia Medyczna Wroclawiu

J. Olesiak

Wrocław University of Science and Technology

H. Leh

Laboratoire de Biologie et de Pharmacologie Appliquee

M. Buckle

Laboratoire de Biologie et de Pharmacologie Appliquee

Liquid Crystals

0267-8292 (ISSN) 1366-5855 (eISSN)

Vol. 38 4 461-468

Ämneskategorier

Kemi

DOI

10.1080/02678292.2011.552740