ISSN:
1432-1327
Keywords:
Key words Cisplatin
;
Antitumor drugs
;
Nuclear magnetic resonance
;
Molecular dynamics
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
Notes:
Abstract d(TpG)– reacts with cis-[Pt(NH3)2(H2O)2]2+ in two steps to yield the platinum chelate cis-[Pt(NH3)2{d(TpG)-N3(1),N7(2)}]. In the latter, hindered rotation of the bases leads to an equilibrium between two rotamers interconverting slowly on the NMR time scale. The structure of the two rotameric chelates was studied by means of 1H NMR and molecular modeling techniques. The major and minor rotamers could be assigned unambiguously to the two head-to-head conformational domains which are characterized by syn/anti and anti/anti sugar-base orientations, respectively. Molecular models derived for both rotamers show that the orientations of the bases are mutually quasi-enantiomeric. The interconversion between the two rotamers (k ≈ 1 s–1 at 293 K) is approximately 104 times faster than the analogous rotamer interconversion observed in cis-[Pt(NH3)2{r(CpG)-N3(1),N7(2)}]+ [Girault J-P, Chottard G, Lallemand J-Y, Huguenin F, Chottard J-C (1984) J Am Chem Soc 106 : 7227–7232], suggesting that the steric clash of the exocyclic amino group of the platinum-bound cytosine with the ligands in cis position is more severe than that of the two thymine oxo groups.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s007750050205
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