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Spontaneous formation of liquid crystalline phases and phase transitions in highly concentrated plasmid DNA

Piotr Hanczyc (Institutionen för kemi- och bioteknik, Fysikalisk kemi) ; K. Matczyszyn ; K. Pawlik ; J. Olesiak ; H. Leh ; M. Buckle
Liquid Crystals (0267-8292). Vol. 38 (2011), 4, p. 461-468.
[Artikel, refereegranskad vetenskaplig]

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.

Nyckelord: plasmid DNA, liquid crystal, cholesteric phase, phase transition, fingerprint-like texture, supercoiling, hyperchromic effect, DNA, isolation techniques, circular dichroism, supercoiled dna, thermal-denaturation, growth temperature, escherichia-coli, nucleic acids, microscopy, dimensions, bacteria, linking, shock

Denna post skapades 2011-05-12. Senast ändrad 2016-08-15.
CPL Pubid: 140604


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Institutioner (Chalmers)

Institutionen för kemi- och bioteknik, Fysikalisk kemi (2005-2014)



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