Reversible B/Z-DNA transition under the low salt condition and non-B-form polydApolydT selectivity by a cubane-like europium-L-aspartic acid complex.
We report here that a cubane-like europium-L-aspartic acid complex at physiological pH can discriminate between DNA structures as judged by the comparison of thermal denaturation, binding stoichiometry, temperature-dependent fluorescence enhancement, and circular dichroism and gel electrophoresis studies. This complex can selectively stabilize non-B-form DNA polydApolydT but destabilize polydGdCpolydGdC and polydAdTpolydAdT. Further studies show that this complex can convert B-form polydGdCpolydGdC to Z-form under the low salt condition at physiological temperature 37 degrees C, and the transition is reversible, similar to RNA polymerase, which turns unwound DNA into Z-DNA and converts it back to B-DNA after transcription. The potential uses of a left-handed helix-selective probe in biology are obvious. Z-DNA is a transient structure and does not exist as a stable feature of the double helix. Therefore, probing this transient structure with a metal-amino acid complex under the low salt condition at physiological temperature would provide insights into their transitions in vivo and are of great interest.
Division of Biological Inorganic Chemistry, Key Laboratory of Rare Earth Chemistry and Physics, Changchun Institute of Applied Chemistry, Graduate School of the Chinese Academy of Sciences, Changchun, Jilin 130022, China.
Haiyuan
H
Zhang
Haijia
H
Yu
Jinsong
J
Ren
Xiaogang
X
Qu
D001224:Aspartic Acid / Q000737:chemistry / Q000502:physiology*; D002942:Circular Dichroism; D003460:Crystallization; D018360:Crystallography, X-Ray; D043542:DNA, Z-Form / Q000737:chemistry / Q000378:metabolism*; D005063:Europium / Q000737:chemistry / Q000502:physiology*; D011067:Poly dA-dT / Q000737:chemistry / Q000378:metabolism*; D012492:Salts; D013056:Spectrophotometry, Ultraviolet
D043542:DNA, Z-Form; D012492:Salts; D011067:Poly dA-dT; D001224:Aspartic Acid; D005063:Europium