[Frontiers in Bioscience E2, 684-693, January 1, 2010]

Beta-Cyclodextrin in DNA decompaction: An imaging approach

Alfredo Gonzalez-Perez

MEMPHYS - Center for Biomembrane Physics, Department of Physics and Chemistry, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark

TABLE OF CONTENTS

1. Abstract
2. Introduction
3. Experimental
3.1. Materials
3.2. Sample preparation
3.3. Fluorescence microscopy
3.4. Negative staining TEM
3.5. Cryo-transmission electron microscopy (cryo-TEM)
4. Results and discussion
4.1. From globule to coil: A non-first order transition
4.2. DNA interaction with CTAB and β-CD
4.3. β-CD as a decompacting agent
5. Conclusions and perspectives
6. Acknowledgements
7. References

1. ABSTRACT

In the present work we investigate the CTAB:DNA complexes decompaction process using β-CD as a decompacting agent. The transition from globules (compacted DNA) to coils (decompacted DNA) was achieved without a coexistence region between coils and globules. This non first-order transition was investigated combining fluorescence microscopy (FM), cryo-transmission electron microscopy (cryo-TEM) and TEM of negatively stained samples. Additionally the presence of multi-globular aggregates in the proximity of the critical transition was elucidated. A possible mechanism for the decompaction process was suggested.