A polarized-light spectroscopy study of interactions of a hairpin polyamide with DNA

Hagelin, Christina,1977Chalmers tekniska högskola,Chalmers University of Technology (författare)

We here study the interactions of a polyamide with large DNA, and compare to those of minor groove binder distamycin (DST), including high ligand/DNA binding ratios. Specific as well as nonspecific binding is probed using polarized-light spectroscopy combined with singular value decomposition analysis. Circular and linear dichroism data confirm binding geometries consistent with minor groove binding for both of the ligands. Interestingly, at high and intermediate ligand/DNA ratios the polyamide exhibits no significant sequence discrimination between mixed-sequence (calf thymus) and AT DNA as compared to DST. Each ligand is concluded to exhibit two different binding modes depending upon ligand/DNA ratio and nucleo-base sequence. At high binding ratios, distinct differences between the ligands are observed: circular dichroism spectra exciton effects provide evidence of bimolecular interactions of the polyamide when bound to AT-DNA, whereas no effects are seen with DST or mixed-sequence DNA. Also linear dichroism indicates that a change in binding geometry occurs at high polyamide/AT ratios, and that the effect occurs only with polyamide in contrast to DST. Since the effect is insignificant with DST, or with calf thymus DNA, it is concluded that it relates to the sizes of the ligands and the minor grooves, becoming critical in the limit of crowding.

Johnsson, RichardLund University,Lunds universitet,Centrum för analys och syntes,Kemiska institutionen,Institutioner vid LTH,Lunds Tekniska Högskola,Centre for Analysis and Synthesis,Department of Chemistry,Departments at LTH,Faculty of Engineering, LTH(Swepub:lu)bioo-rjo (författare)
Ellervik, UlfLund University,Lunds universitet,Centrum för analys och syntes,Kemiska institutionen,Institutioner vid LTH,Lunds Tekniska Högskola,Centre for Analysis and Synthesis,Department of Chemistry,Departments at LTH,Faculty of Engineering, LTH(Swepub:lu)ok2-uel (författare)
Fox, K.R.University of Southampton (författare)
Lincoln, Per,1958Chalmers tekniska högskola,Chalmers University of Technology(Swepub:cth)lincoln (författare)
Nordén, Bengt,1945Chalmers tekniska högskola,Chalmers University of Technology(Swepub:cth)norden (författare)
Caesar, Christina E. B. (författare)
Chalmers tekniska högskolaCentrum för analys och syntes (creator_code:org_t)

Av författaren/redakt...: Hagelin, Christi ...; Johnsson, Richar ...; Ellervik, Ulf; Fox, K.R.; Lincoln, Per, 19 ...; Nordén, Bengt, 1 ...; visa fler...; Caesar, Christin ...; visa färre...

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