ISSN:
1432-1327
Keywords:
Key words Circular dichroism
;
Molecular modeling
;
Oligonucleotides
;
Platinum complexes
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
Notes:
Abstract The asymmetrical platinum complex [PtCl2(N,N-dmen)] (N,N-dmen=N,N-dimethylethylenediamine) reacts with the dinucleotide GpG to form two isomeric chelates of the formula [Pt(N,N-dmen)(GpG)]+ [9]. One of the isomers forms two stable rotamers separable by HPLC, whereas the other apparently prefers one single rotameric form. The favored conformations of these three forms were elucidated by means of molecular mechanics and dynamics techniques. In parallel, we have prepared the adduct, isolated the three rotamers, and recorded their solution circular dichroism (CD) spectra. For the first time we were thus able to correlate the CD features of individual rotamers of a cis-Pt(GpG) chelate with their structures. We show here that the two forms labeled in Inagaki's paper 1'e and 2e have the same right-handed helicoidal arrangement of the guanine bases but display different CD spectra in which the prominent bands have inverted signs. Thus, base-base interactions cannot be the principal cause of the CD of these compounds.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s007750050006
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