The structure of the NTPase that powers DNA packaging into Sulfolobus turreted icosahedral virus 2

Abstract

Biochemical reactions powered by ATP hydrolysis are fundamental for the movement of molecules and cellular structures. One such reaction is the encapsidation of the double-stranded DNA (dsDNA) genome of an icosahedrally symmetric virus into a pre-formed procapsid with the help of a genome-translocating NTPase. Such NTPases have been characterized in detail from both RNA and tailed DNA viruses. We present four crystal structures and the biochemical activity of a thermophilic NTPase, B204, from the nontailed, membrane-containing, hyperthermoacidophilic archaeal dsDNA virus Sulfolobus turreted icosahedral virus 2. These are the first structures of a genome-packaging NTPase from a nontailed, dsDNA virus with an archaeal host. The four structures highlight the catalytic cycle of B204, pinpointing the molecular movement between substrate-bound (open) and empty (closed) active sites. The protein is shown to bind both single-stranded and double-stranded nucleic acids and to have an optimum activity at 80°C and pH 4.5. The overall fold of B204 places it in the FtsK-HerA superfamily of P-loop ATPases, whose cellular and viral members have been suggested to share a DNA-translocating mechanism. Viruses with double-stranded DNA (dsDNA) or dsRNA ge-nomes often package their genome through a channel in a preformed capsid or procapsid (1). Genome translocation is pow-ered by NTP hydrolysis catalyzed by a DNA- (or RNA)-packaging enzyme (1). In tailed dsDNA viruses, the channel is a dodecameric ring called the connector, located at a viral 5-fold vertex referred t

Download PDF:
_{Sorry, we are unable to provide the full text but you may find it at the following location(s):}

http://jvi.asm.org/content/87/... (external link)

http://jvi.asm.org/content/87/... (external link)

http://citeseerx.ist.psu.edu/v... (external link)