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dc.contributor.advisorChakravarthy, Akhil Ranjan
dc.contributor.authorPatra, Ashis Kumar
dc.date.accessioned2009-09-03T05:29:00Z
dc.date.accessioned2018-07-30T15:03:27Z
dc.date.available2009-09-03T05:29:00Z
dc.date.available2018-07-30T15:03:27Z
dc.date.issued2009-09-03T05:29:00Z
dc.date.submitted2007-12
dc.identifier.urihttp://etd.iisc.ac.in/handle/2005/610
dc.description.abstractPhoto sensitizers showing visible light induced DNA cleavage activity are of current importance for medicinal applications related to photodynamic therapy (PTD) considering greater skin penetration of light near 700 nm. While organic molecules and complexes of 4d-5d metal ions are extensively studied for their DNA photo-damage properties in UV and visible light, the chemistry of 3D metal complexes showing visible light-induced DNA cleavage activity is relatively unexplored efforts have been made in this thesis work to design new ternary copper (II) complexes having a-amino acids Such copper (II) complexes with tunable coordination geometry could find potential applications in PDT. Ternary Copper (II) complexes containing L-methionine, S-methy1-L-cysteine and phenanthroline bases are prepared and characterized. They display DNA binding and visible light induced DNA cleavage activity. An enhancement of the DNA cleavage activity is observed for analogous ternary copper (II) complexes contained L-lysine with a pendant cationic amine moiety as a photo-induced DNA Cleavage activity using binary and ternary copper (II) complexes of L-arginine and phenanthroline bases. We have observed AT selective DNA binding and visible light –induced DNA cleavage activity. The crescent-shaped bis-arginine Copper (II) complex mimics the natural antiviral antibiotic netropsin. T o investigate the role of the pendant groups of the amino acids, we have explored the DNA binding and DNA cleavage activity of analogues L-glutamine and L-asparagine complexes. We have prepared ternary copper (II) complexes containing two photosensitizers, viz., L-tryptophan (L-trp) and dipyridoquininoxaline/dipyridophenazine to achieve double strand breaks forming linear DNA. Complex [Cu(L-trp)(dppz)(H2O)+ shows a stacking arrangement of the indole and dppz rings giving a separation that fits with the base pair separation of ds-DNA. Photosensitizes in these complexes approach two different complementary stands of the ds-DNA, leading to double strand breaks and formation of linear DNA. Mechanistic studies on the DNA photocleavage reactions reveal the formation of singlet oxygen(1O2)species by a type-II pathway in preference to the hydroxyl radical generation. A process leading to an efficient DNA cleavage activity on visible light irradiation. The observation of sequence selectivity and double strand DNA cleavage on red light exposure by national design of the complexes is significant considering importance of the results in the chemistry of photodynamic therapy of cancer. The results of this dissertation open up new avenues for designing and developing 3d metal-based photosensitizers with potential utility in nulcleic acid chemistry.en
dc.language.isoen_USen
dc.relation.ispartofseriesG22166en
dc.subjectCopper Complexesen
dc.subjectAmino Acidsen
dc.subjectOrganic Conjugatesen
dc.subjectTransition Metal Complexesen
dc.subjectCopper Complexes - DNA Bindingen
dc.subjectCopper Complexes - DNA Cleavageen
dc.subjectCopper Complexes - Crystallographyen
dc.subjectTernary Copper (II) Complexesen
dc.subjectPhenanthroline Basesen
dc.subjectPhoto-induced DNA Cleavageen
dc.subjectCopper(II) Complexesen
dc.subject.classificationInorganic Biochemistryen
dc.titleStudies On The Photo-induced DNA Cleavage Activity Of α-Amino Acid Copper Complexes Having Phenanthroline Basesen
dc.typeThesisen
dc.degree.namePhDen
dc.degree.levelDoctoralen
dc.degree.disciplineFaculty of Scienceen


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