title: Impact of histidine residue on chelating ability of 2'-deoxyriboadenosine.
abstract: Copper(II) complexes with a new chelator-type nucleoside-histidine modified 2'-deoxyriboadenosine (N-[(9-β-D-2'-deoxyribofuranosylpurin-6-yl)-carbamoyl]histidine) were studied by potentiometric and spectroscopic (UV-visible, CD, EPR) techniques, in conjunction with computer modeling optimization. The ligand can act as bidentate or tridentate depending on pH range. In acidic pH a very stable dimeric complex Cu(2)L(2) predominates with coordination spheres of both metal ions composed of oxygen atoms from carboxylic groups, one oxygen atom from ureido group and two nitrogen atoms derived from purine base and histidine ring. Above pH 5, deprotonation of carbamoyl nitrogens leads to the formation of CuL(2), Cu(2)L(2)H(-1) and Cu(2)L(2)H(-2) species. The CuL(2)H(-1) and CuL(2)H(-2) complexes with three or four nitrogens in Cu(II) coordination sphere have been detected in alkaline medium. Our findings suggest that N-[(9-beta-D-2'-deoxyribofuranosylpurin-6-yl)-carbamoyl]histidine chelates copper(II) ions very efficiently. The resulting complex might be used as an alternative base-pairing mode in which hydrogen-bonded base pairs present in natural DNA are replaced by metal-mediated ones.
authors: Institute of General Food Chemistry, Technical University of Łódź, ul. Stefanowskiego 4/10, 90-924 Łódź, Poland. elalodyg@p.lodz.pl
authors: Elżbieta
authors: E
authors: Lodyga-Chruścińska
authors: Stanisław
authors: S
authors: Ołdziej
authors: Elżbieta
authors: E
authors: Sochacka
authors: Karolina
authors: K
authors: Korzycka
authors: Longin
authors: L
authors: Chruściński
authors: Giovanni
authors: G
authors: Micera
authors: Daniele
authors: D
authors: Sanna
authors: Monika
authors: M
authors: Turek
authors: Justyna
authors: J
authors: Pawlak
mesh_terms: D000241:Adenosine / Q000032:analysis / Q000138:chemical synthesis* / Q000378:metabolism; D020029:Base Pairing; D002614:Chelating Agents / Q000032:analysis / Q000138:chemical synthesis* / Q000378:metabolism; D002942:Circular Dichroism; D056831:Coordination Complexes / Q000032:analysis / Q000138:chemical synthesis* / Q000378:metabolism; D003300:Copper / Q000737:chemistry / Q000378:metabolism*; D004247:DNA / Q000737:chemistry / Q000378:metabolism*; D015342:DNA Probes / Q000032:analysis / Q000138:chemical synthesis* / Q000378:metabolism; D003854:Deoxyribonucleotides / Q000032:analysis / Q000138:chemical synthesis* / Q000378:metabolism; D004578:Electron Spin Resonance Spectroscopy; D006639:Histidine / Q000737:chemistry / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008024:Ligands; D008958:Models, Molecular; D011199:Potentiometry; D011522:Protons; D013056:Spectrophotometry, Ultraviolet
chemical_list: D002614:Chelating Agents; D056831:Coordination Complexes; D015342:DNA Probes; D003854:Deoxyribonucleotides; D008024:Ligands; D011522:Protons; D006639:Histidine; D003300:Copper; D004247:DNA; D000241:Adenosine