Recognition of left-handed Z-DNA of short unmodified oligonucleotides under physiological ionic strength conditions.
The left-handed Z-DNA form of the short unmodified alternating guanine-cytosine oligonucleotides, 5'-(dGdC)(24) and 5'-(dGdC)(18), was selectively detected under physiological ionic strength and pH conditions using the anionic nickel(II) porphyrin, NiTPPS. No spectroscopic signal was observed for NiTPPS with any right-handed oligonucleotides under identical conditions. The 48mer 5'-(dGdC)(24) Z-form was detected at concentrations as low as 100nM. The binding of NiTPPS to the B- and Z-oligonucleotides was studied quantitatively by UV-vis absorption and circular dichroism spectroscopies. NiTPPS was found to be a universal DNA binder, with binding affinity and geometry depending on the ionic composition of the solution, rather than on the DNA helical twist. This is the first example of a successful spectroscopic detection of the Z-DNA of short unmodified oligonucleotides under physiological pH and ionic strength conditions.
Department of Chemistry, University of Wyoming, Laramie, WY 82071, USA.
Alessandro
A
D'Urso
Jung Kyu
JK
Choi
Murtaza
M
Shabbir-Hussain
Fidelis N
FN
Ngwa
Maria I
MI
Lambousis
Roberto
R
Purrello
Milan
M
Balaz
D002942:Circular Dichroism; D003596:Cytosine / Q000737:chemistry*; D043542:DNA, Z-Form / Q000737:chemistry*; D006147:Guanine / Q000737:chemistry*; D009532:Nickel / Q000737:chemistry; D009690:Nucleic Acid Conformation; D009841:Oligonucleotides / Q000737:chemistry*; D009994:Osmolar Concentration
D043542:DNA, Z-Form; D009841:Oligonucleotides; D006147:Guanine; D009532:Nickel; D003596:Cytosine