SPERMINE-DNA COMPLEXES BUILD UP METASTABLE STRUCTURES - SMALL-ANGLE X-RAY-SCATTERING AND CIRCULAR-DICHROISM STUDIES

Spermine-DNA complexes have been examined by small-angle and wide-angle X-ray scattering as well as by circular dichroism studies.Condensed complexes are building up below a critical ionic strength. We have found that at one and the same ionic strength condensed complexes having two different supramolecular structures (Type I and Type II) can coexist. The structure of the condensates depends on the method of condensate formation. Phase transitions between these structures can be induced by thermal treatment. We conclude from these facts that with polyamine-DNA condensates metastable structures are of importance. © 1979 Information Retrieval Limited.