Applications of atomic force microscope in the study of DNA-protein interactions.

摘要

Atomic Force Microscope (AFM) has been developed to study the interaction of biologically interesting molecules. This study explores the possible application of AFM in the study of DNA-Protein interaction.;The first study investigated the interaction between the 3.4kb 5;AFM was used to image a 1.1kb fragment of Staphylococcus aureus HSP70 operon that contains a palindromic nucleotide sequence. Structural analysis of the fragment revealed a quadruplet that consists of a pair of stem-loops for which a novel 'SL2S' (Stem-Loop-Loop-Stem) model was proposed. AFM also revealed the binding of ORF37 to the quadruplet, establishing a molecular mechanism for this heat shock gene expression.;AFM was used to image entire human topoisomerase II a (p170). Molecular images obtained by AFM revealed homodimers exhibiting a "heart or donut-like" structure with a large axial pore.;AFM was used to investigate the action of the transcriptional repressor ATF3 on chopp10. AFM studies identified a ATF3 binding site, different from the Ap1 site and a C/EBP site that have been shown to be important in the repression of chopp10 gene expression by ATF3.;AFM was used to determine the smallest number of hexameric rings necessary to unwind DNA. A 1.13kb DNA fragment with 30 bases of non complimentary ssDNA tails on one end was used as a substrate to mimic replication fork. Analysis of images of 4A