since significant band shifts were also observed in the absorption spectra of dna in the presence of these transition metal ions , we have concluded that the differences observed between the c spectrum previously reported and that found for these ions is attributable to changes in the absorption properties of the monomers due to cation association , rather than dramatic differences in comformational properties of the c secondary structure of dna in the presence of these ions .
C0007447
cation
C0022023
ions