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Assembly of Nucleosomal Arrays from Recombinant Core Histones and Nucleosome Positioning DNA
Published on: September 10, 2013
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Structure of histone-based chromatin in Archaea
Francesca Mattiroli1, Sudipta Bhattacharyya2, Pamela N Dyer1
1Department of Chemistry and Biochemistry, University of Colorado Boulder, Boulder, CO 80309, USA.
Science (New York, N.Y.)
|August 12, 2017
Summary
Archaeal histones and eukaryotic histones evolved from a common ancestor. Archaeal histone-DNA complexes reveal DNA compaction mechanisms predating the eukaryotic nucleosome.
Area of Science:
- Biochemistry
- Molecular Biology
- Structural Biology
Background:
- Most Archaea possess small basic proteins evolutionarily related to eukaryotic core histones.
- Understanding the structure and function of these archaeal proteins is key to deciphering DNA compaction mechanisms.
Purpose of the Study:
- To determine the crystal structure of an archaeal histone-DNA complex.
- To elucidate the evolutionary origins of the eukaryotic nucleosome and DNA compaction.
Main Methods:
- X-ray crystallography was used to obtain the high-resolution structure of the archaeal histone-DNA complex.
- Site-directed mutagenesis was employed to investigate the role of conserved residues.
Main Results:
- DNA wraps around an extended polymer of archaeal histone homodimers in a superhelical structure.
- This archaeal structure shares geometric similarities with DNA organization in eukaryotic nucleosomes.
- Mutating a conserved glycine residue destabilized archaeal chromatin, affecting growth and transcription.
Conclusions:
- The histone-based DNA compaction mechanism existed before the emergence of the nucleosome.
- This study sheds light on the evolutionary trajectory leading to the eukaryotic nucleosome.
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