ABSTRACT
This chapter focuses on the use of transient electric birefringence (TEB) to analyze the curvature of naturally occurring, random-sequence deoxyribonucleic acid (DNA) molecules, with an emphasis on experimental results. Restriction fragments containing the putative bend centers can then be isolated and analyzed by more quantitative techniques, such as TEB. TEB is particularly suitable for analyzing DNA curvature, because the measured rotational relaxation times are approximately proportional to the third power of macromolecular length. The chapter describes the use of TEB to analyze the curvature of three naturally occurring, mixed-sequence DNAs: an electrophoretically anomalous 153-bp restriction fragment taken from an intergenic region in plasmid pBR322. It shows that restriction fragments taken from the origin of replication of bacteriophage M13, which has been cloned into the plasmid Litmus 28; and restriction fragments taken from the VP1 gene in the simian virus 40 minichromosome. TEB is a powerful technique for determining the intrinsic curvature of naturally occurring, random sequence DNA molecules.
