Kinetics and mechanism for platination of thione-containing nucleotides and oligonucleotides: evaluation of the salt dependence

Forskningsoutput: TidskriftsbidragArtikel i vetenskaplig tidskrift

Standard

Kinetics and mechanism for platination of thione-containing nucleotides and oligonucleotides: evaluation of the salt dependence. / Kjellström, Johan; Elmroth, Sofi.

I: Journal of Biological Inorganic Chemistry, Vol. 8, Nr. 1-2, 2003, s. 38-44.

Forskningsoutput: TidskriftsbidragArtikel i vetenskaplig tidskrift

Harvard

APA

CBE

MLA

Vancouver

Author

RIS

TY - JOUR

T1 - Kinetics and mechanism for platination of thione-containing nucleotides and oligonucleotides: evaluation of the salt dependence

AU - Kjellström, Johan

AU - Elmroth, Sofi

PY - 2003

Y1 - 2003

N2 - Reactions of cis-[PtCl(NH3)(CyNH2)(OH2)](+) (Cy = cyclohexyl) with thione-containing single-stranded oligonucleotides d(T8XT8) and d(XT16) (X = I-s6 or U-s4) and the mononucleotides 4-thiouridine ((UMP)-U-s4) and 6-mercaptoinosine ((IMP)-I-s6) have been studied in aqueous solution at pH 4.1. The reaction kinetics was followed using HPLC methodology as a function of ionic strength in the interval 5.0 mM less than or equal to I less than or equal to 300 mM. A two-fold kinetic preference for reaction with the I-s6 moiety over U-s4 is observed in both monomeric and oligomeric systems. The rate for adduct formation with the oligonucleotides d(T8XT8) and d(XT16) decreases with increasing ionic strength of the medium. The effect is most pronounced for adduct formation with the middle positions, e.g. for d((T8IT8)-I-s6): k(2,app) = 130 M-1 s(-1) and 13 M-1 s(-1) at I = 5.0 and 300 mM, respectively, and slightly less pronounced for adduct formation at the end positions, e.g. for d((IT16)-I-s6): k(2,app) = 130 M-1 s(-1) and 11 M-1 s(-1) at I = 5.0 and 300 mM, respectively. Analysis of the salt dependence using the Bronsted-Debye-Huckel relationship shows that the reactions with the monomers are well described as an interaction between a monovalent cation and a monovalent anion. In contrast, a similar analysis of the oligonucleotide reactions indicates influence from polyelectrolyte effects. The results support a mechanism in which pre-association on the DNA surface precedes adduct formation, regardless of the exact location of the final binding site.

AB - Reactions of cis-[PtCl(NH3)(CyNH2)(OH2)](+) (Cy = cyclohexyl) with thione-containing single-stranded oligonucleotides d(T8XT8) and d(XT16) (X = I-s6 or U-s4) and the mononucleotides 4-thiouridine ((UMP)-U-s4) and 6-mercaptoinosine ((IMP)-I-s6) have been studied in aqueous solution at pH 4.1. The reaction kinetics was followed using HPLC methodology as a function of ionic strength in the interval 5.0 mM less than or equal to I less than or equal to 300 mM. A two-fold kinetic preference for reaction with the I-s6 moiety over U-s4 is observed in both monomeric and oligomeric systems. The rate for adduct formation with the oligonucleotides d(T8XT8) and d(XT16) decreases with increasing ionic strength of the medium. The effect is most pronounced for adduct formation with the middle positions, e.g. for d((T8IT8)-I-s6): k(2,app) = 130 M-1 s(-1) and 13 M-1 s(-1) at I = 5.0 and 300 mM, respectively, and slightly less pronounced for adduct formation at the end positions, e.g. for d((IT16)-I-s6): k(2,app) = 130 M-1 s(-1) and 11 M-1 s(-1) at I = 5.0 and 300 mM, respectively. Analysis of the salt dependence using the Bronsted-Debye-Huckel relationship shows that the reactions with the monomers are well described as an interaction between a monovalent cation and a monovalent anion. In contrast, a similar analysis of the oligonucleotide reactions indicates influence from polyelectrolyte effects. The results support a mechanism in which pre-association on the DNA surface precedes adduct formation, regardless of the exact location of the final binding site.

KW - 4-thiouridine

KW - 6-mercaptoinosine

KW - kinetics

KW - platinum

KW - DNA

U2 - 10.1007/s00775-002-0384-9

DO - 10.1007/s00775-002-0384-9

M3 - Article

VL - 8

SP - 38

EP - 44

JO - Journal of Biological Inorganic Chemistry

JF - Journal of Biological Inorganic Chemistry

SN - 1432-1327

IS - 1-2

ER -