May 16, 2015

Modes of Escherichia coli Dps Interaction with DNA as Revealed by Atomic Force Microscopy

PloS One
Vladislav V MelekhovSergey S Antipov

Abstract

Multifunctional protein Dps plays an important role in iron assimilation and a crucial role in bacterial genome packaging. Its monomers form dodecameric spherical particles accumulating ~400 molecules of oxidized iron ions within the protein cavity and applying a flexible N-terminal ends of each subunit for interaction with DNA. Deposition of iron is a well-studied process by which cells remove toxic Fe2+ ions from the genetic material and store them in an easily accessible form. However, the mode of interaction with linear DNA remained mysterious and binary complexes with Dps have not been characterized so far. It is widely believed that Dps binds DNA without any sequence or structural preferences but several lines of evidence have demonstrated its ability to differentiate gene expression, which assumes certain specificity. Here we show that Dps has a different affinity for the two DNA fragments taken from the dps gene regulatory region. We found by atomic force microscopy that Dps predominantly occupies thermodynamically unstable ends of linear double-stranded DNA fragments and has high affinity to the central part of the branched DNA molecule self-assembled from three single-stranded oligonucleotides. It was proposed that Dp...Continue Reading

Mentioned in this Paper

Direct Repeat
Study
TFDP2 gene
Ethanol
Crystal - Body Material
Nucleosomes
Histone antigen
Deoxyribonuclease I
Molecular Helix
Glycerin

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