Interaction between Nonhistone Protein HMGB1 and Linker Histone H1 Facilitates the Formation of Structurally Ordered DNA-Protein Complexes

Alexander Polyanichko,Elena Chikhirzhina

doi:10.1155/2012/213031

Alexander Polyanichko, Elena Chikhirzhina

Open Access

https://doi.org/10.1155/2012/213031

Copy DOI

Abstract

The structural organization of the DNA complexes with nonhistone chromosomal protein and linker histone H1 was studied using circular dichroism spectroscopy (CD) and atomic force microscopy (AFM). It has been shown that due to the interaction between HMGB1 and H1 highly ordered DNA-protein complexes emerge in the solution. Their spectral properties are found to be similar to those of DNA/HMGB1-(AB) complexes, reported earlier. AFM images reveal the formation of fibril-like structures in the solution. We suggest that the electrostatic screening of the HMGB1 C-terminal domain by histone H1 facilitates stronger interaction of the HMGB1/H1 with DNA and the formation of the ordered supramolecular DNA-protein complexes.

Highlights

A great variety of DNA-binding proteins interact with DNA in cell nucleus-forming intricate DNAprotein complexes
The aim of the present study is to investigate the structural organization of the HMGB1DNA complexes in presence of linker histone H1 using circular dichroism spectroscopy (CD) and atomic force microscopy (AFM)
In case of circular dichroism (CD) spectroscopy, it leads to the formation of characteristic spectral pattern, called ψ-type CD spectra

Summary

Introduction

A great variety of DNA-binding proteins interact with DNA in cell nucleus-forming intricate DNAprotein complexes. The common feature of the proteins within the family is their DNA-binding motif, often called HMGB-domain [1, 2]. The members of the family are able to distinguish and preferably bind to distorted regions in DNA, such as four-way junctions, binding sites of the anticancer drug cisplatin, and great variety of other bends and crossovers [3]. Another abundant chromatin protein with somewhat similar properties is linker histone H1 [4,5,6], which binds to a linker DNA at the entrance/exit of the nucleosome

Objectives

Methods

Results