title: Experimental studies on the nature of bonding of DNA*bipyridyl-(ethylenediamine)platinum(II) and DNA*netropsin complexes in solution and oriented wet-spun films.
abstract: The stability of complexes of NaDNA with bipyridyl- (ethylenediamine)platinum(II) (abbreviated [(bipy)Pt(en)](2+)) and with netropsin has been studied using two techniques: (i) ultraviolet (UV) melting experiments were done on NaDNA* [(bipy)Pt(en)](2+), showing that the [(bipy)Pt(en)](2+) ligand stabilizes the DNA double helix structure; and (ii) swelling measurements (via optical microscopy) as a function of relative humidity were done on wet-spun oriented films of NaDNA*[(bipy)Pt(en)](2+) and of NaDNA*netropsin. The swelling data shows that an irreversible transition of the films occurs at high relative humidity, first for the NaDNA*netropsin, then for pure NaDNA, and lastly for the NaDNA*[(bipy)Pt(en)](2+). These results are indicative that the [(bipy)Pt(en)](2+) complex stabilizes the intermolecular bonds which mediate the film swelling characteristics. A model is suggested for the binding of [(bipy)Pt(en)](2+) to DNA to explain why the swelling experiments show this ligand as increasing the intermolecular bond strength between the DNA double helices, while netropsin decreases this degree of stabilization.
authors.affiliation: Department of Physics, Geology, and Astronomy, The University of Tennessee, Chattanooga, TN 37403, USA.
authors.forename: R L
authors.initials: RL
authors.lastname: Marlowe
authors.forename: A
authors.initials: A
authors.lastname: Szabó
authors.forename: S A
authors.initials: SA
authors.lastname: Lee
authors.forename: A
authors.initials: A
authors.lastname: Rupprecht
mesh_terms: D015082:2,2'-Dipyridyl / Q000031:analogs & derivatives / Q000737:chemistry*; D001665:Binding Sites; D004247:DNA / Q000737:chemistry*; D018736:DNA Adducts / Q000737:chemistry*; D005029:Ethylenediamines; D006813:Humidity; D009429:Netropsin / Q000737:chemistry*; D009690:Nucleic Acid Conformation; D009944:Organoplatinum Compounds / Q000737:chemistry*; D010984:Platinum; D012996:Solutions; D013056:Spectrophotometry, Ultraviolet; D013816:Thermodynamics
chemical_list: D018736:DNA Adducts; C460911:DNA-bipyridyl-(ethylenediamine)platinum(II); D005029:Ethylenediamines; D009944:Organoplatinum Compounds; D012996:Solutions; D010984:Platinum; D015082:2,2'-Dipyridyl; C031234:ethylenediamine; D009429:Netropsin; D004247:DNA