Heterohexamer of 56- and 63-kDa Gene 4 Helicase-Primase of Bacteriophage T7 in DNA Replication

Zhang, Huidong; Lee, Seung-Joo; Kulczyk, Arkadiusz W.; Zhu, Bin; Richardson, Charles C.

doi:10.1074/jbc.m112.401158

Cited by 16 publications

(8 citation statements)

References 49 publications

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“…One form is ~63 kDa containing both primase and helicase domains and another ~56 kDa truncated gp4 protein lacks the zinc binding domain of the primase. Recent studies have shown that these two proteins oligomerize and form a heterohexamers which show higher helicase activity than 63 kDa gp4 protein product alone (Zhang et al ., ). As PfPrex primase‐helicase domain shows primary sequence similarity with T7 bacteriophage gene 4 protein, it is possible that the two prominent forms of PfPrex helicase primase (~70 and ~55 kDa respectively) may have similar function like T7 gp4 protein.…”

Section: Resultsmentioning

confidence: 97%

“…The polymerase domain of PfPrex is separated from the primase–helicase domain but whether the primase–helicase domain works as a complex or individually is not known. Interestingly, in T7 bacteriophage, two forms (63‐kDa full‐length gp4 and 56‐kDa truncated gp4) of gene4 protein (gp4, primase‐helicase) are expressed and together they form heterohexamer to perform as a fully functional protein (Zhang et al ., ). It is possible that P .…”

Section: Introductionmentioning

confidence: 97%

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Plasmodium falciparumsingle-stranded DNA-binding protein (PfSSB) interacts with PfPrex helicase and modulates its activity

Bhowmick

Dhar

2013

FEMS Microbiol Lett

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Plasmodium falciparum (Pf) apicoplast is an essential organelle harbouring a ~35-kb circular genome. Prokaryotic nature of this organelle and its components makes it an attractive therapeutic target. The single-stranded DNA-binding protein (SSB) and multidomain protein PfPrex are important apicoplast replication proteins. However, regulation of these proteins through protein-protein interaction remains largely unknown. Here, we report that P. falciparum single-stranded DNA-binding protein (PfSSB) interacts with PfPrex helicase and modulates its activity. N-terminal domain of PfSSB is involved in this interaction, whereas C-terminal domain plays a pivotal role in the modulation of helicase activity. These results further, to our knowledge, understand apicoplast DNA replication.

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Section: Resultsmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 97%

Plasmodium falciparumsingle-stranded DNA-binding protein (PfSSB) interacts with PfPrex helicase and modulates its activity

Bhowmick

Dhar

2013

FEMS Microbiol Lett

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“…Western blot analysis has identified numerous cleavage products of Prex, although it is not clear which represent functional proteins. It is possible there are several forms of the mature active Prex proteins, as multiple isoforms of the bacteriophage T7 primase-helicase have been observed [28]. Identification of the protease(s) responsible for separating the Prex primase, helicase, and polymerase domains would lead to a better understanding of posttranslational modifications of apicoplast proteins and identify potential new drug targets.…”

Section: Prex (Transcription Transport and Processing)mentioning

confidence: 98%

Replication and maintenance of the Plasmodium falciparum apicoplast genome

Milton

Nelson

2016

Molecular and Biochemical Parasitology

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“…The hexameric gp4 has primase activity on its N-terminus to initialize Okazaki fragment synthesis, and Hel activity on its C-terminus to unwind the dsDNA. The Hel domain on gp4 is a member of the superfamily 4 (SF4) Hels and uses the energy from ATP or dTTP hydrolysis to migrate in the 5′-to-3′ direction on the lagging strand DNA [ 20 , 21 ]. The tight DNA binding by gp4 helicase domains promotes substrate engagement of the primase [ 20 ].…”

Section: Hel–pol Coupling In Bacteriophage T7 Dna Replicationmentioning

confidence: 99%

DNA Helicase–Polymerase Coupling in Bacteriophage DNA Replication

Gao

2021

Viruses

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Bacteriophages have long been model systems to study the molecular mechanisms of DNA replication. During DNA replication, a DNA helicase and a DNA polymerase cooperatively unwind the parental DNA. By surveying recent data from three bacteriophage replication systems, we summarized the mechanistic basis of DNA replication by helicases and polymerases. Kinetic data have suggested that a polymerase or a helicase alone is a passive motor that is sensitive to the base-pairing energy of the DNA. When coupled together, the helicase–polymerase complex is able to unwind DNA actively. In bacteriophage T7, helicase and polymerase reside right at the replication fork where the parental DNA is separated into two daughter strands. The two motors pull the two daughter strands to opposite directions, while the polymerase provides a separation pin to split the fork. Although independently evolved and containing different replisome components, bacteriophage T4 replisome shares mechanistic features of Hel–Pol coupling that are similar to T7. Interestingly, in bacteriophages with a limited size of genome like Φ29, DNA polymerase itself can form a tunnel-like structure, which encircles the DNA template strand and facilitates strand displacement synthesis in the absence of a helicase. Studies on bacteriophage replication provide implications for the more complicated replication systems in bacteria, archaeal, and eukaryotic systems, as well as the RNA genome replication in RNA viruses.

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Heterohexamer of 56- and 63-kDa Gene 4 Helicase-Primase of Bacteriophage T7 in DNA Replication

Cited by 16 publications

References 49 publications

Plasmodium falciparumsingle-stranded DNA-binding protein (PfSSB) interacts with PfPrex helicase and modulates its activity

Plasmodium falciparumsingle-stranded DNA-binding protein (PfSSB) interacts with PfPrex helicase and modulates its activity

Replication and maintenance of the Plasmodium falciparum apicoplast genome

DNA Helicase–Polymerase Coupling in Bacteriophage DNA Replication

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