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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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Diagram comparing the activities of the S. solfataricus TopR1 and P. calidifontis PcalRG reverse gyrases on synthetic Holliday junctions. Light blue arrows indicate PcalRG activities (ATP-dependent unwinding and ATP-indepedent annealing); green arrows indicate TopR1 ATP-independent unwinding; the four DNA strands are shown in white, pink, black and blue, respectively. Whereas TopR1 unwinding activity proceeds up to single strand oligonucleotides, the main products of PcalRG unwinding are Y-shaped forks, likely because single strand products are annealed back [104,113].
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ijms-15-17162-f004: Diagram comparing the activities of the S. solfataricus TopR1 and P. calidifontis PcalRG reverse gyrases on synthetic Holliday junctions. Light blue arrows indicate PcalRG activities (ATP-dependent unwinding and ATP-indepedent annealing); green arrows indicate TopR1 ATP-independent unwinding; the four DNA strands are shown in white, pink, black and blue, respectively. Whereas TopR1 unwinding activity proceeds up to single strand oligonucleotides, the main products of PcalRG unwinding are Y-shaped forks, likely because single strand products are annealed back [104,113].

Mentions: More recently, it was reported that PcalRG shows a real helicase activity, namely ATP-hydrolysis dependent unwinding of ds DNA and HJ structures [104]; interestingly, at higher enzyme/DNA ratios the reaction is reversed leading to re-annealing of DNA (Figure 4).


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)

Diagram comparing the activities of the S. solfataricus TopR1 and P. calidifontis PcalRG reverse gyrases on synthetic Holliday junctions. Light blue arrows indicate PcalRG activities (ATP-dependent unwinding and ATP-indepedent annealing); green arrows indicate TopR1 ATP-independent unwinding; the four DNA strands are shown in white, pink, black and blue, respectively. Whereas TopR1 unwinding activity proceeds up to single strand oligonucleotides, the main products of PcalRG unwinding are Y-shaped forks, likely because single strand products are annealed back [104,113].
© Copyright Policy
Related In: Results  -  Collection

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

ijms-15-17162-f004: Diagram comparing the activities of the S. solfataricus TopR1 and P. calidifontis PcalRG reverse gyrases on synthetic Holliday junctions. Light blue arrows indicate PcalRG activities (ATP-dependent unwinding and ATP-indepedent annealing); green arrows indicate TopR1 ATP-independent unwinding; the four DNA strands are shown in white, pink, black and blue, respectively. Whereas TopR1 unwinding activity proceeds up to single strand oligonucleotides, the main products of PcalRG unwinding are Y-shaped forks, likely because single strand products are annealed back [104,113].
Mentions: More recently, it was reported that PcalRG shows a real helicase activity, namely ATP-hydrolysis dependent unwinding of ds DNA and HJ structures [104]; interestingly, at higher enzyme/DNA ratios the reaction is reversed leading to re-annealing of DNA (Figure 4).

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
Related in: MedlinePlus