RESUMO
DNA replication is essential for all life forms. Although the process is fundamentally conserved in the three domains of life, bioinformatic, biochemical, structural, and genetic studies have demonstrated that the process and the proteins involved in archaeal DNA replication are more similar to those in eukaryal DNA replication than in bacterial DNA replication, but have some archaeal-specific features. The archaeal replication system, however, is not monolithic, and there are some differences in the replication process between different species. In this review, the current knowledge of the mechanisms governing DNA replication in Archaea is summarized. The general features of the replication process as well as some of the differences are discussed.
Assuntos
Archaea/genética , Replicação do DNA/genética , DNA Arqueal/genética , DNA Helicases/genética , Proteínas de Ligação a DNA/genéticaRESUMO
Replicative DNA helicases are essential cellular enzymes that unwind duplex DNA in front of the replication fork during chromosomal DNA replication. Replicative helicases were discovered, beginning in the 1970s, in bacteria, bacteriophages, viruses, and eukarya, and, in the mid-1990s, in archaea. This year marks the 20th anniversary of the first report on the archaeal replicative helicase, the minichromosome maintenance (MCM) protein. This minireview summarizes 2 decades of work on the archaeal MCM.
Assuntos
Archaea/enzimologia , Archaea/genética , Proteínas de Manutenção de Minicromossomo/genética , Proteínas de Manutenção de Minicromossomo/metabolismo , Pesquisa , Proteínas Arqueais/genética , Proteínas Arqueais/metabolismo , Bactérias/genética , Bactérias/metabolismo , Replicação do DNA , DNA Arqueal , Eucariotos/genética , Eucariotos/metabolismo , História do Século XX , História do Século XXI , Proteínas de Manutenção de Minicromossomo/química , Domínios Proteicos , Pesquisa/história , Relação Estrutura-AtividadeRESUMO
DNA replication plays an essential role in all life forms. Research on archaeal DNA replication began approximately 20 years ago. Progress was hindered, however, by the lack of genetic tools to supplement the biochemical and structural studies. This has changed, however, and genetic approaches are now available for several archaeal species. One of these organisms is the thermophilic euryarchaeon Thermococcus kodakarensis. In the present paper, the recent developments in the biochemical, structural and genetic studies on the replication machinery of T. kodakarensis are summarized.
Assuntos
Replicação do DNA , DNA Arqueal/genética , Thermococcus/genética , DNA Arqueal/biossínteseRESUMO
PCNA (proliferating-cell nuclear antigen) is a ring-shaped protein that encircles duplex DNA and plays an essential role in many DNA metabolic processes. The PCNA protein interacts with a large number of cellular factors and modulates their enzymatic activities. In the present paper, we summarize the structures, functions and interactions of the archaeal PCNA proteins.
Assuntos
Proteínas Arqueais/química , Proteínas Arqueais/metabolismo , Antígeno Nuclear de Célula em Proliferação/química , Antígeno Nuclear de Célula em Proliferação/metabolismo , Proteínas Arqueais/genética , DNA/genética , DNA/metabolismo , Replicação do DNA , Humanos , Modelos Moleculares , Antígeno Nuclear de Célula em Proliferação/genética , Conformação ProteicaRESUMO
During chromosomal DNA replication, the replicative helicase unwinds the duplex DNA to provide the single-stranded DNA substrate for the polymerase. In archaea, the replicative helicase is the minichromosome maintenance (MCM) complex. The enzyme utilizes the energy of ATP hydrolysis to translocate along one strand of the duplex and unwind the complementary strand. Much progress has been made in elucidating structure and function since the first report on the biochemical properties of an archaeal MCM protein in 1999. We now know the biochemical and structural properties of the enzyme from several archaeal species and some of the mechanisms by which the enzyme is regulated. This review summarizes recent studies on the archaeal MCM protein and discusses the implications for helicase function and DNA replication in archaea.
Assuntos
Archaea/metabolismo , Proteínas Arqueais/metabolismo , DNA Helicases/metabolismo , Replicação do DNA , Archaea/genética , Domínio Catalítico , DNA Arqueal/biossíntese , Modelos Moleculares , Ligação Proteica , Estrutura Quaternária de Proteína , Estrutura Terciária de ProteínaRESUMO
In order for any organism to replicate its DNA, a helicase must unwind the duplex DNA in front of the replication fork. In archaea, the replicative helicase is the MCM (minichromosome maintenance) helicase. Although much is known about the biochemical properties of the MCM helicase, the mechanism of assembly at the origin of replication is unknown. In the present paper, several possible mechanisms for the loading process are described.
Assuntos
Archaea/enzimologia , Proteínas Arqueais/metabolismo , DNA Helicases/metabolismo , Replicação do DNA , DNA Helicases/química , DNA Arqueal/metabolismoRESUMO
Chromosomal DNA replication starts at a specific region called an origin of replication. Until recently, all organisms were thought to require origins to replicate their chromosomes. It was recently discovered that some archaeal species do not utilize origins of replication under laboratory growth conditions.
Assuntos
Archaea/genética , Genes Arqueais/genética , Origem de Replicação/genética , Origem de Replicação/fisiologia , Archaea/crescimento & desenvolvimento , Archaea/metabolismo , Proteínas Arqueais/genética , Proteínas Arqueais/metabolismo , Cromossomos de Archaea/genética , Replicação do DNA/genética , Replicação do DNA/fisiologia , DNA Arqueal/genética , Viabilidade Microbiana/genéticaRESUMO
Until recently, the only archaeon for which a bona fide origin of replication was reported was Pyrococcus abyssi, where a single origin was identified. Although several in silico analyses have suggested that some archaeal species might contain more than one origin, this has only been demonstrated recently. Two studies have shown that multiple origins of replication function in two archaeal species. One study identified two origins of replication in the archaeon Sulfolobus solfataricus, whereas a second study used a different technique to show that both S. solfataricus and Sulfolobus acidocaldarius have three functional origins. These are the first reports of archaea having multiple origins. This finding has implications for research on the mechanisms of DNA replication and evolution.
Assuntos
Archaea/genética , Origem de Replicação , Archaea/metabolismo , Proteínas Arqueais/genética , Proteínas Arqueais/metabolismo , Centrômero/genética , Cromossomos de Archaea/genética , Replicação do DNA/genética , DNA Arqueal/genética , Sulfolobus/genéticaRESUMO
Living organisms are divided into three domains: Bacteria, Archaea, and Eukarya. Whereas Bacteria and Archaea are both prokaryotes, proteins involved in information processes; replication, transcription, and translation, are more similar in Archaea and Eukarya. Here the history of the research on archaeal DNA replication is summarized and the future of the field is discussed.
Assuntos
Archaea/fisiologia , Replicação do DNA , DNA Arqueal/genéticaRESUMO
Whereas the process of DNA replication is fundamentally conserved in the three domains of life, the archaeal system is closer to that of eukarya than bacteria. In the time since the complete genome sequences of several members of the archaeal domain became available, there has been a burst of research on archaeal DNA replication. These studies have led to both expected and surprising findings. This review summarizes the search for origins of replication in archaea, and our current knowledge of initiation, the process by which replication origins are recognized, the DNA molecule is unwound and the replicative helicase is loaded onto the DNA in preparation for DNA synthesis. The similarities and differences of the initiation process in archea, bacteria and eukarya are also summarized.