Sequential action of ATPase, ATP, ADP, Pi and dsDNA in procapsid-free system to enlighten mechanism in viral dsDNA packaging.
Nucleic Acids Res
; 40(6): 2577-86, 2012 Mar.
Article
em En
| MEDLINE
| ID: mdl-22110031
ABSTRACT
Many cells and double-stranded DNA (dsDNA) viruses contain an AAA(+) ATPase that assembles into oligomers, often hexamers, with a central channel. The dsDNA packaging motor of bacteriophage phi29 also contains an ATPase to translocate dsDNA through a dodecameric channel. The motor ATPase has been investigated substantially in the context of the entire procapsid. Here, we report the sequential action between the ATPase and additional motor components. It is suggested that the contact of ATPase to ATP resulted in its conformational change to a higher binding affinity toward dsDNA. It was found that ATP hydrolysis led to the departure of dsDNA from the ATPase/dsDNA complex, an action that is speculated to push dsDNA to pass the connector channel. Our results suggest that dsDNA packaging goes through a combined effort of both the gp16 ATPase for pushing and the channel as a one-way valve to control the dsDNA translocation direction. Many packaging models have previously been proposed, and the packaging mechanism has been contingent upon the number of nucleotides packaged per ATP relative to the 10.5 bp per helical turn for B-type dsDNA. Both 2 and 2.5 bp per ATP have been used to argue for four, five or six discrete steps of dsDNA translocation. Combination of the two distinct roles of gp16 and connector renews the perception of previous dsDNA packaging energy calculations and provides insight into the discrepancy between 2 and 2.5 bp per ATP.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Proteínas Virais
/
DNA Viral
/
Trifosfato de Adenosina
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Fagos Bacilares
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Adenosina Trifosfatases
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Montagem de Vírus
Idioma:
En
Revista:
Nucleic Acids Res
Ano de publicação:
2012
Tipo de documento:
Article
País de afiliação:
Estados Unidos