Liquid crystalline microphases of DNA molecules complexed with compounds of platinum(II)

The formation of liquid crystalline microphases (0.3 M NaClO4, and 120 and 170 mg PEG/ml) from low-Mr DNA (salmon sperm) complexed with cis and trans dichlorodiamine-platinum(II) was investigated. It was shown that the amplitude of the negative band in the CD spectrum, characteristic of a liquid crystalline microphase of DNA, decreased upon complexing with platinum compounds. It was estimated that the influence of cis Pt(II) on the optical properties of liquid crystalline microphase of DNA molecules strongly differed from the effect of trans Pt(II); the phenomenon did not depend on [PEG]. The reasons of the decrease of the negative band in the CD spectra of the DNA liquid crystalline microphases are discussed.