The Structure of the Phage T4 DNA Packaging Motor Suggests a Mechanism Dependent on Electrostatic Forces

Journal Article · Tue Jun 30 00:00:00 EDT 2009 · Cell

DOI:https://doi.org/10.1016/j.cell.2008.11.015· OSTI ID:1007116

Sun, Siyang; Kondabagil, Kiran; Draper, Bonnie; Alam, Tanfis I; Bowman, Valorie D; Zhang, Zhihong; Hegde, Shylaja; Fokine, Andrei; Rossmann, Michael G; Rao, Venigalla B ^[1]

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1. CUA

Viral genomes are packaged into procapsids by powerful molecular motors. We report the crystal structure of the DNA packaging motor protein, gene product 17 (gp17), in bacteriophage T4. The structure consists of an N-terminal ATPase domain, which provides energy for compacting DNA, and a C-terminal nuclease domain, which terminates packaging. We show that another function of the C-terminal domain is to translocate the genome into the procapsid. The two domains are in close contact in the crystal structure, representing a tensed state. A cryo-electron microscopy reconstruction of the T4 procapsid complexed with gp17 shows that the packaging motor is a pentamer and that the domains within each monomer are spatially separated, representing a relaxed state. These structures suggest a mechanism, supported by mutational and other data, in which electrostatic forces drive the DNA packaging by alternating between tensed and relaxed states. Similar mechanisms may occur in other molecular motors.

• Research Organization: Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
• Sponsoring Organization: USDOE
• OSTI ID: 1007116
• Journal Information: Cell, Vol. 135, Issue (7) ; 12, 2008; ISSN 0092-8674
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

36 MATERIALS SCIENCE
BACTERIOPHAGES
COMPACTING
CRYSTAL STRUCTURE
DNA
ELECTROSTATICS
GENES
MICROSCOPY
MONOMERS
MOTORS
NUCLEASES
PACKAGING