Probing the mechanical stability of bridged DNA-H-NS protein complexes by single-molecule AFM pulling

Sci Rep. 2017 Nov 10;7(1):15275. doi: 10.1038/s41598-017-15477-4.

Abstract

Atomic force microscopy (AFM) has proven to be a powerful tool for the study of DNA-protein interactions due to its ability to image single molecules at the nanoscale. However, the use of AFM in force spectroscopy to study DNA-protein interactions has been limited. Here we developed a high throughput, AFM based, pulling assay to measure the strength and kinetics of protein bridging of DNA molecules. As a model system, we investigated the interactions between DNA and the Histone-like Nucleoid-Structuring protein (H-NS). We confirmed that H-NS both changes DNA rigidity and forms bridges between DNA molecules. This straightforward methodology provides a high-throughput approach with single-molecule resolution which is widely applicable to study cross-substrate interactions such as DNA-bridging proteins.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • DNA, Bacterial / chemistry*
  • DNA, Bacterial / ultrastructure
  • DNA-Binding Proteins / chemistry*
  • Escherichia coli / chemistry*
  • Escherichia coli Proteins / chemistry*
  • Fimbriae Proteins / chemistry*
  • Microscopy, Atomic Force*

Substances

  • DNA, Bacterial
  • DNA-Binding Proteins
  • Escherichia coli Proteins
  • FimG protein, E coli
  • Fimbriae Proteins