Stabilization of a DNA duplex under molecular crowding conditions of PEG.
A living cell generally contains macromolecules occupying 20-40% of the total volume. To mimic the crowded cellular condition, we prepared solutions including poly(ethylene glycol) (PEG) as a cosolute and investigated the influence of the cosolute on the DNA duplex stability. In the presence of PEG 200 or PEG 8000, the Tm (melting temperature) of a self-complementary duplex of 5'-dATGCGCAT-3' decreased by 11.8 degrees C in the presence of 20 wt% PEG200 and by 1.5 degrees C in the presence of 20 wt% PEG 8000. The dln K(obs) vs. dln a(w) plots for PEG 200 and PEG 8000 were linear with a negative slope, suggesting the association of water molecules upon the duplex formation. Interestingly, when the NaCl concentration decreased from 1 M to 400 mM, the Tm increased in the presence of PEGs. Our results imply that the nucleic acid stabilities in a living cell may be different from those in in vitro conditions.
Karimata
Hisae
H
Department of Chemistry, Faculty of Science and Engineering, Konan University, 8-9-1 Okamoto, Higashinada-ku, Kobe 658-8501, Japan.
Nakano
Shu-ichi
S
Ohmichi
Tatsuo
T
Kawakami
Junji
J
Sugimoto
Naoki
N
D020029:Base Pairing; D002470:Cell Survival; D004247:DNA / Q000737:chemistry*; D009691:Nucleic Acid Denaturation; D009692:Nucleic Acid Heteroduplexes / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry*; D013816:Thermodynamics
D009692:Nucleic Acid Heteroduplexes; D011092:Polyethylene Glycols; D004247:DNA