d(GC) - Association of Biotechnology and Pharmacy
d(GC) - Association of Biotechnology and Pharmacy
d(GC) - Association of Biotechnology and Pharmacy
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Current Trends in <strong>Biotechnology</strong> <strong>and</strong> <strong>Pharmacy</strong><br />
Vol. 6 (2) 204-209 April 2012, ISSN 0973-8916 (Print), 2230-7303 (Online)<br />
upon the species present under a given set <strong>of</strong><br />
conditions, this prompted us to carry out to study<br />
the Al-DNA interaction using Al maltol at neutral<br />
pH.<br />
Materials <strong>and</strong> Methods<br />
Chemicals: Poly d(<strong>GC</strong>).d(<strong>GC</strong>) (Sodium salt),<br />
poly d(AT).d(AT) (Sodium salt), Aluminum<br />
chloride hexahydrate, Maltol, HEPES, EDTA <strong>and</strong><br />
EtBr were procured from Sigma chemicals. Poly<br />
d(<strong>GC</strong>).d(<strong>GC</strong>) <strong>and</strong> poly d(AT). d(AT) was used<br />
without further purification. Al-maltol has been<br />
synthesized according to the method <strong>of</strong><br />
Finneagen et.al. (19). Purity <strong>of</strong> Al-maltol has been<br />
checked by UV <strong>and</strong> IR spectroscopy.<br />
Circular dichroism (CD) Studies: The Circular<br />
dichroism spectra (190-300 nm) were recorded<br />
for poly d(<strong>GC</strong>).d(<strong>GC</strong>) <strong>and</strong> poly d(AT).d(AT) in<br />
the absence <strong>and</strong> presence <strong>of</strong> Al-maltol (50-<br />
200μM ) in 1μM HEPES at pH 7.0 on a JASCO-J-<br />
715 Spectropolarimeter at 20 o C by using 1 mm cell.<br />
Each spectra is the average <strong>of</strong> four recordings.<br />
Results<br />
CD spectra: Poly d(<strong>GC</strong>).d(<strong>GC</strong>) was titrated with<br />
Al-maltol (50-200µm ) <strong>and</strong> CD spectra were<br />
recorded for each titration at pH.7.0 in 1mM HEPES<br />
buffer. Normal B-DNA conservative spectrum is<br />
observed for poly d(<strong>GC</strong>).d(<strong>GC</strong>) alone (Fig 1.a).<br />
At 50µm level <strong>of</strong> Al maltol there is disappearance<br />
<strong>of</strong> large positive peak at 190nm, a strong B-DNA<br />
peak (Fig 1.b). The group <strong>of</strong> spectra (Fig 1.c,d&e)<br />
which possesses features <strong>of</strong> left-h<strong>and</strong>ed Z –DNA<br />
helix were treated with 100, 150 <strong>and</strong> 200 μM <strong>of</strong><br />
Al-maltol respectively. The spectra have two<br />
negative peaks at 290nm <strong>and</strong> at 198 nm. There is<br />
also shift in the 200nm cross-over <strong>of</strong> the B-DNA to<br />
lower wavelength (