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Chromatin structure and dynamics in hot environments: architectural proteins and DNA topoisomerases of thermophilic archaea.

Visone V, Vettone A, Serpe M, Valenti A, Perugino G, Rossi M, Ciaramella M - Int J Mol Sci (2014)

Bottom Line: Elucidation of chromatin composition and regulation is a critical issue in biology, because of the intimate connection of chromatin with all the essential information processes (transcription, replication, recombination, and repair).Chromatin proteins include architectural proteins and DNA topoisomerases, which regulate genome structure and remodelling at two hierarchical levels.In these organisms, which live at high environmental temperature (>80 °C <113 °C), chromatin proteins and modulation of the DNA secondary structure are concerned with the problem of DNA stabilization against heat denaturation while maintaining its metabolic activity.

View Article: PubMed Central - PubMed

Affiliation: Institute of Biosciences and Bioresources, National Research Council of Italy, Naples 80131, Italy. valeria.visone@ibbr.cnr.it.

ABSTRACT
In all organisms of the three living domains (Bacteria, Archaea, Eucarya) chromosome-associated proteins play a key role in genome functional organization. They not only compact and shape the genome structure, but also regulate its dynamics, which is essential to allow complex genome functions. Elucidation of chromatin composition and regulation is a critical issue in biology, because of the intimate connection of chromatin with all the essential information processes (transcription, replication, recombination, and repair). Chromatin proteins include architectural proteins and DNA topoisomerases, which regulate genome structure and remodelling at two hierarchical levels. This review is focussed on architectural proteins and topoisomerases from hyperthermophilic Archaea. In these organisms, which live at high environmental temperature (>80 °C <113 °C), chromatin proteins and modulation of the DNA secondary structure are concerned with the problem of DNA stabilization against heat denaturation while maintaining its metabolic activity.

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Structure of the M. fervidus histone tetramer in complex with DNA (PDB ID: 1B67), with the HmfA (orange) and HMfB (cyano) subunits.
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ijms-15-17162-f001: Structure of the M. fervidus histone tetramer in complex with DNA (PDB ID: 1B67), with the HmfA (orange) and HMfB (cyano) subunits.

Mentions: Archaea belonging to the sub-domains Euryarchaea, Nanoarchaea and Thaumarchaea and some Crenarchaea encode homologs of eukaryotic histones [11,14,17,18,19,20,21]. Archaeal histones possess a typical fold resembling eukaryotic H3 and H4, consisting of three hydrophobic α-helices, and interact with the DNA minor groove. In solution, archaeal histones form dimers, whereas they bind DNA as tetramers or, less frequently, as hexamers [21,22,23]. In vitro, each histone tetramer protects about 60 bases of dsDNA; at low histone concentrations, DNA is sharply bent in complexes, suggesting wrapping of DNA around a histone tetramer [18,19,20,21]. Under these conditions, histone tetramers induce negative supercoiling of circular DNA molecules, whereas positive supercoiling is observed at non-physiological ionic strength [19,20,21]. Many Archaea encode multiple histone homologs; the most studied histone proteins from hyperthermophilic archaea are HMfA and HMfB from Methanothermus fervidus. These proteins can form either homodimers or heterodimers, which differ in their DNA binding properties and compact DNA into nucleosome-like structures [18,22] (Figure 1). Histone paralogs can be differently expressed in different growth phases and conditions, suggesting that the dynamic histone composition may shape chromosome structure differently [24,25].


Chromatin structure and dynamics in hot environments: architectural proteins and DNA topoisomerases of thermophilic archaea.

Visone V, Vettone A, Serpe M, Valenti A, Perugino G, Rossi M, Ciaramella M - Int J Mol Sci (2014)

Structure of the M. fervidus histone tetramer in complex with DNA (PDB ID: 1B67), with the HmfA (orange) and HMfB (cyano) subunits.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4200833&req=5

ijms-15-17162-f001: Structure of the M. fervidus histone tetramer in complex with DNA (PDB ID: 1B67), with the HmfA (orange) and HMfB (cyano) subunits.
Mentions: Archaea belonging to the sub-domains Euryarchaea, Nanoarchaea and Thaumarchaea and some Crenarchaea encode homologs of eukaryotic histones [11,14,17,18,19,20,21]. Archaeal histones possess a typical fold resembling eukaryotic H3 and H4, consisting of three hydrophobic α-helices, and interact with the DNA minor groove. In solution, archaeal histones form dimers, whereas they bind DNA as tetramers or, less frequently, as hexamers [21,22,23]. In vitro, each histone tetramer protects about 60 bases of dsDNA; at low histone concentrations, DNA is sharply bent in complexes, suggesting wrapping of DNA around a histone tetramer [18,19,20,21]. Under these conditions, histone tetramers induce negative supercoiling of circular DNA molecules, whereas positive supercoiling is observed at non-physiological ionic strength [19,20,21]. Many Archaea encode multiple histone homologs; the most studied histone proteins from hyperthermophilic archaea are HMfA and HMfB from Methanothermus fervidus. These proteins can form either homodimers or heterodimers, which differ in their DNA binding properties and compact DNA into nucleosome-like structures [18,22] (Figure 1). Histone paralogs can be differently expressed in different growth phases and conditions, suggesting that the dynamic histone composition may shape chromosome structure differently [24,25].

Bottom Line: Elucidation of chromatin composition and regulation is a critical issue in biology, because of the intimate connection of chromatin with all the essential information processes (transcription, replication, recombination, and repair).Chromatin proteins include architectural proteins and DNA topoisomerases, which regulate genome structure and remodelling at two hierarchical levels.In these organisms, which live at high environmental temperature (>80 °C <113 °C), chromatin proteins and modulation of the DNA secondary structure are concerned with the problem of DNA stabilization against heat denaturation while maintaining its metabolic activity.

View Article: PubMed Central - PubMed

Affiliation: Institute of Biosciences and Bioresources, National Research Council of Italy, Naples 80131, Italy. valeria.visone@ibbr.cnr.it.

ABSTRACT
In all organisms of the three living domains (Bacteria, Archaea, Eucarya) chromosome-associated proteins play a key role in genome functional organization. They not only compact and shape the genome structure, but also regulate its dynamics, which is essential to allow complex genome functions. Elucidation of chromatin composition and regulation is a critical issue in biology, because of the intimate connection of chromatin with all the essential information processes (transcription, replication, recombination, and repair). Chromatin proteins include architectural proteins and DNA topoisomerases, which regulate genome structure and remodelling at two hierarchical levels. This review is focussed on architectural proteins and topoisomerases from hyperthermophilic Archaea. In these organisms, which live at high environmental temperature (>80 °C <113 °C), chromatin proteins and modulation of the DNA secondary structure are concerned with the problem of DNA stabilization against heat denaturation while maintaining its metabolic activity.

Show MeSH