Single-molecule studies of viral DNA packaging

Smith, Douglas E.

doi:10.1016/j.coviro.2011.05.023

Cited by 60 publications

(59 citation statements)

References 50 publications

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“…At a given external osmotic pressure, by varying the salinity of solution, one can also vary the amount of DNA ejected. Interestingly, it has been shown that monovalent counterions such as NaCl have a negligible effect on the DNA ejection process [3,12,13]. In contrast, multivalent counterions such as Mg +2 , CoHex +3 (Co-hexamine), Spd +3 (spermidine) or Spm +4 (spermine) exert strong effect, both qualitatively and quantitatively different from that of monovalent counterions.…”

Section: Introductionmentioning

confidence: 98%

Strongly correlated electrostatics of viral genome packaging

Nguyen

2013

J Biol Phys

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The problem of viral packaging (condensation) and ejection from viral capsid in the presence of multivalent counterions is considered. Experiments show divalent counterions strongly influence the amount of DNA ejected from bacteriophage. In this paper, the strong electrostatic interactions between DNA molecules in the presence of multivalent counterions is investigated. It is shown that experiment results agree reasonably well with the phenomenon of DNA reentrant condensation. This phenomenon is known to cause DNA condensation in the presence of tri-or tetra-valent counterions. For divalent counterions, the viral capsid confinement strongly suppresses DNA configurational entropy, therefore the correlation between divalent counterions is strongly enhanced causing similar effect. Computational studies also agree well with theoretical calculations.

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Section: Introductionmentioning

confidence: 98%

Strongly correlated electrostatics of viral genome packaging

Nguyen

2013

J Biol Phys

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“…Phage terminases are among the strongest and fastest known molecular machines. 35 The T4 packaging motor has an average translocation speed of ~700 bp/sec, and can achieve rates as high as 2000 bp/sec. 35,36 The motor can exert forces larger than 60 pN to overcome the pressure generated inside the capsid by the packaged DNA.…”

Section: Capsid Assemblymentioning

confidence: 99%

Molecular architecture of tailed double-stranded DNA phages

2014

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“…These molecular motors can work against a force larger than 50 pN and package DNA at high rates, placing them among the most powerful molecular motors in nature (9,11). Most phage DNA packaging motor proteins are bifunctional enzymes that integrate two types of enzymatic activities, the ATPase and the nuclease, as required by the concatemeric nature of the packaging substrates.…”

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confidence: 99%

Structures of the phage Sf6 large terminase provide new insights into DNA translocation and cleavage

Zhao

Christensen

Kamau

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

102

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Many DNA viruses use powerful molecular motors to cleave concatemeric viral DNA into genome-length units and package them into preformed procapsid powered by ATP hydrolysis. Here we report the structures of the DNA-packaging motor gp2 of bacteriophage Sf6, which reveal a unique clade of RecA-like ATPase domain and an RNase H-like nuclease domain tethered by a regulatory linker domain, exhibiting a strikingly distinct domain arrangement. The gp2 structures complexed with nucleotides reveal, at the atomic detail, the catalytic center embraced by the ATPase domain and the linker domain. The gp2 nuclease activity is modulated by the ATPase domain and is stimulated by ATP. An extended DNA-binding surface is formed by the linker domain and the nuclease domain. These results suggest a unique mechanism for translation of chemical reaction into physical motion of DNA and provide insights into coordination of DNA translocation and cleavage in a viral DNA-packaging motor, which may be achieved via linker-domain-mediated interdomain communication driven by ATP hydrolysis.terminase | virus assembly | genome packaging M ost double-stranded DNA (dsDNA) viruses package their genome into preformed protein shells in an active manner using virally encoded molecular motors, as in tailed dsDNA bacteriophages (1, 2), herpesviruses (3), adenoviruses (4), and poxviruses (5). In tailed dsDNA bacteriophages and herpesviruses, the newly synthesized viral DNA in host cells exists as tandem concatemers, each composed of multiple copies of unit-length genome (6, 7). The viral DNA-packaging motor (also known as terminase large subunit or large terminase) cleaves concatemeric viral DNA into units of or near the genomic length and pumps each into a preformed capsid precursor termed procapsid powered by ATP hydrolysis (2,6,8).The DNA-packaging motors of dsDNA bacteriophages package DNA highly densely into the capsid, resulting in an internal pressure of as high as 50 atmospheres, more than 10 times that found in any other living system (9, 10). These molecular motors can work against a force larger than 50 pN and package DNA at high rates, placing them among the most powerful molecular motors in nature (9, 11). Most phage DNA packaging motor proteins are bifunctional enzymes that integrate two types of enzymatic activities, the ATPase and the nuclease, as required by the concatemeric nature of the packaging substrates. Resolving DNA concatemers into units and packaging into procapsid must be precisely coordinated, and the nuclease activity may only be activated at the initiation step of DNA packaging and upon completion of each packaging cycle.Structures of phage T4 terminase large subunit gp17 revealed an ATPase domain belonging to the additional-strand catalytic glutamate (ASCE) superfamily, and a model for DNA translocation dependent on electrostatic forces was proposed (12, 13). Nevertheless, this model was not supported by the structure of phage SPP1 G2P nuclease domain, as the proposed secondary DNA-binding surface during DNA translocation...

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Single-molecule studies of viral DNA packaging

Cited by 60 publications

References 50 publications

Strongly correlated electrostatics of viral genome packaging

Strongly correlated electrostatics of viral genome packaging

Molecular architecture of tailed double-stranded DNA phages

Structures of the phage Sf6 large terminase provide new insights into DNA translocation and cleavage

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