Interaction of Zn(2+) ions with single-stranded polyU and polyC in neutral solutions.
Effect of Zn(2+) ions on the conformation of single-stranded polynucleotides polyU and polyC in a wide temperature range at pH 7 was studied by differential UV spectroscopy and by thermal denaturation. The atoms coordinating Zn(2+) ions were determined (O4 and N3 in polyU and N3 in polyC). A three-dimensional phase diagram and its two-dimensional components were constructed for a polyC-Zn(2+) system. The phase diagram revealed a region in which ordered single-stranded structures, stabilized by Zn(2+)-mediated cross-links involving N3 atom of cytosine, are formed. The phase diagram also demonstrated that the behavior of the polyC-Zn(2+) system is similar to the effect of retrograde condensation observed in some binary solutions of simple liquids. A dependence of Zn(2+)-polyC binding constant on the metal ion concentration was obtained. The reason why zinc-induced transition of the sequences with adenine-uracil (AU) base pairs from A-form geometry to a metallized m-form requires higher pH compared to the sequences comprised of guanine-cytosine (GC) base pairs is explained. This information can be useful for the development of possible technological applications based on m-DNA.
†B. I. Verkin Institute for Low Temperature Physics and Engineering, National Academy of Sciences of Ukraine, 47 Lenin Avenue, Kharkov, 61103, Ukraine.
V A
VA
Sorokin
†B. I. Verkin Institute for Low Temperature Physics and Engineering, National Academy of Sciences of Ukraine, 47 Lenin Avenue, Kharkov, 61103, Ukraine.
E L
EL
Usenko
†B. I. Verkin Institute for Low Temperature Physics and Engineering, National Academy of Sciences of Ukraine, 47 Lenin Avenue, Kharkov, 61103, Ukraine.
V A
VA
Valeev
‡O. Ya. Usikov Institute for Radiophysics and Electronics, National Academy of Sciences of Ukraine, 12 Proskura Street, Kharkov, 61085, Ukraine.
Ekaterina G
EG
Berezniak
§Institute of Organic Chemistry and Biochemistry, Academy of Sciences, Flemingovo náměstí 2, 16610, Prague, Czech Republic.
V V
VV
Andrushchenko
D000225:Adenine / Q000737:chemistry; D002412:Cations / Q000737:chemistry*; D003596:Cytosine / Q000737:chemistry*; D005615:Freezing; D006147:Guanine / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D012996:Solutions; D013057:Spectrum Analysis; D013696:Temperature; D014498:Uracil / Q000737:chemistry*; D015032:Zinc / Q000737:chemistry*
D002412:Cations; D012996:Solutions; D014498:Uracil; D006147:Guanine; D003596:Cytosine; D015032:Zinc; D000225:Adenine