Packaging of viral genomes is a fundamental process in biology. In many DNA viruses this reaction is powered by a large (M.W. ~1.5MDa) genome-packaging motor, which is formed by a terminase holoenzyme assembled to a dodecameric portal protein. This macromolecular complex functions like a chemical motor, which hydrolyzes ATP to translocate a copy of the viral genome inside a preformed capsid, at rates as high as 2000 bases per second. In addition to being the fastest and most powerful engine in nature, the genome-packaging motor is also an intriguing molecular machine, which is poorly characterized both in structure and catalytic mechanisms. In this grant, we will use a combination of crystallographic and biochemical techniques to characterize the structure of the bacteriophage P22 genome-packaging motor. Building upon the structure of P22 portal protein, which was recently determined in my laboratory, our work will focus on the chemistry of P22 terminase that is a functional ATPase in the motor. The structural characterization of P22 terminase in complex with portal protein will provide a structural framework to decipher how, within the packaging motor, terminase couples ATP hydrolysis to translocation of viral genomes. In addition, since terminases are highly conserved in herpesviruses, the work proposed in this grant will also provide a logical framework to begin structural characterization of packaging motors in pathogenic human viruses.
Specific aims of our work are: 1.) to determine the structure of the P22 terminase holoenzyme assembled at the portal protein vertex; 2.) to define how small terminase subunit stimulates large terminase ATPase activity during genome-packaging.

Public Health Relevance

Viral genome-translocating motors are multisubunit ATPases that burn ATP to power packaging of viral genomes inside a preformed capsid. In this grant, we propose to study the structure and activity of the bacteriophage P22 genome-translocating motor. Our work will determine how one of smallest motors in nature couples chemical energy to genome translocation.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM100888-04
Application #
8927018
Study Section
Macromolecular Structure and Function C Study Section (MSFC)
Program Officer
Flicker, Paula F
Project Start
2012-08-01
Project End
2016-07-31
Budget Start
2015-08-01
Budget End
2016-07-31
Support Year
4
Fiscal Year
2015
Total Cost
$294,500
Indirect Cost
$104,500
Name
Thomas Jefferson University
Department
Biochemistry
Type
Schools of Medicine
DUNS #
053284659
City
Philadelphia
State
PA
Country
United States
Zip Code
19107
Parent, Kristin N; Schrad, Jason R; Cingolani, Gino (2018) Breaking Symmetry in Viral Icosahedral Capsids as Seen through the Lenses of X-ray Crystallography and Cryo-Electron Microscopy. Viruses 10:
Lokareddy, Ravi K; Sankhala, Rajeshwer S; Roy, Ankoor et al. (2017) Portal protein functions akin to a DNA-sensor that couples genome-packaging to icosahedral capsid maturation. Nat Commun 8:14310
Cingolani, Gino; Panella, Andrea; Perrone, Maria Grazia et al. (2017) Structural basis for selective inhibition of Cyclooxygenase-1 (COX-1) by diarylisoxazoles mofezolac and 3-(5-chlorofuran-2-yl)-5-methyl-4-phenylisoxazole (P6). Eur J Med Chem 138:661-668
Motwani, Tina; Lokareddy, Ravi K; Dunbar, Carmen A et al. (2017) A viral scaffolding protein triggers portal ring oligomerization and incorporation during procapsid assembly. Sci Adv 3:e1700423
Wu, Wei; Sankhala, Rajeshwer S; Florio, Tyler J et al. (2017) Synergy of two low-affinity NLSs determines the high avidity of influenza A virus nucleoprotein NP for human importin ? isoforms. Sci Rep 7:11381
Sankhala, Rajeshwer S; Lokareddy, Ravi K; Begum, Salma et al. (2017) Three-dimensional context rather than NLS amino acid sequence determines importin ? subtype specificity for RCC1. Nat Commun 8:979
Bhardwaj, Anshul; Sankhala, Rajeshwer S; Olia, Adam S et al. (2016) Structural Plasticity of the Protein Plug That Traps Newly Packaged Genomes in Podoviridae Virions. J Biol Chem 291:215-26
Sankhala, Rajeshwer S; Lokareddy, Ravi K; Cingolani, Gino (2016) Divergent Evolution of Nuclear Localization Signal Sequences in Herpesvirus Terminase Subunits. J Biol Chem 291:11420-33
Sankhala, Rajeshwer S; Lokareddy, Ravi K; Cingolani, Gino (2015) A Greasy Aid to Capsid Assembly: Lessons from a Salty Virus. Structure 23:1777-1779
Pumroy, Ruth A; Ke, Song; Hart, Darren J et al. (2015) Molecular determinants for nuclear import of influenza A PB2 by importin ? isoforms 3 and 7. Structure 23:374-84

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