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Principal Investigator: Makayla Leroux
Organization: UNIVERSITY OF CONNECTICUT STORRS
Fiscal Year: 2024
Award: $46,476
Funding agency: National Institute of General Medical Sciences
PROJECT SUMMARY
Assembly of dsDNA viruses, including the tailed bacteriophages, herpesviruses, and adenoviruses, is a highly
coordinated process involving a series of protein interactions that lead to the formation of an infectious virion. The
central goal of this research is to achieve a detailed mechanistic understanding of the specific
protein:protein interactions that govern this assembly process. During assembly, proteins interact
temporally, driven by their conformational plasticity. The dodecameric portal protein complex, which is essential
for tailed dsDNA virus assembly, exemplifies this. In bacteriophage P22, a model for dsDNA viruses, scaffolding
protein drives the oligomerization of portal protein monomers into rings which are subsequently incorporated into
procapsids (PCs). Terminase proteins then preferentially bind the PC conformation of portal, and package DNA
until the head is full. At this point, portal undergoes a conformational switch to its mature virion (MV) form that
triggers the release of the terminase proteins and the binding of proteins that stopper the portal channel resulting
in the complete MV. Portal takes on another distinct conformation from its PC and MV forms after the virion
injects its DNA into host cells. Despite the portal complex being critical for successful virion assembly, owing to
it being the conduit for DNA translocation, its roles during DNA packaging and signaling for the completion of
packaging have not been mechanistically defined. The central hypothesis is that conformational changes of the
portal complex are required to regulate the processes involved in successful viral maturation. I will test this
hypothesis using bacteriophage P22 which provides an excellent dsDNA model assembly system. Overall, its
simple genetics and well-established biochemistry offer advantages over more complex dsDNA viruses. The
experiments proposed in Aim 1 will elucidate the signal for DNA packaging completion by interrogating portal
protein variants’ ability to make infectious phages with the appropriate morphology that package the correct
amount of DNA. In Aim 2, I will obtain the cryo-EM structure of the portal complex bound to terminase, which
has not been solved at high-resolution. Collectively, these data will represent a significant advancement of our
understanding of the dsDNA viral assembly pathway by shedding light on how conformational changes of portal
drive DNA packaging. Overall, elucidation of the details involved in P22 assembly can lead to the identification
of potential anti-viral drug target sites to inhibit assembly of dsDNA human pathogens.
Terms: <Adenoviridae><Adenoviruses><Affect><Anti-viral Agents><Assay><Bacteriophage P22><Bacteriophages><Binding><Binding Proteins><Bioassay><Biochemistry><Biological Assay><Biological Chemistry><Capsid Proteins><Cell Body><Cell Communication and Signaling><Cell Signaling><Cells><Charge><Coat Proteins><Complex><Cryo-electron Microscopy><Cryoelectron Microscopy><DNA><DNA Packaging><Data><Deoxyribonucleic Acid><Development><Double Stranded DNA Virus><Double-Stranded DNA><Drug Targeting><Electron Cryomicroscopy><Enterobacteria phage P22><Fluorescence><Genetic><Genome><Goals><Head><Health><Herpesviridae><Herpesviruses><Human><Intracellular Communication and Signaling><K element><Ligand Binding Protein><Ligand Binding Protein Gene><Light><Methods><Modeling><Modern Man><Molecular Configuration><Molecular Conformation><Molecular Interaction><Molecular Stereochemistry><Morphology><Mutate><P22 Phage><Pathway interactions><Phages><Photoradiation><Potassium><Process><Production><Protein Binding><Proteins><Research><Resolution><Role><S enterica serovar Typhimurium><S typhimurium><S. enterica Typhimurium><S. enterica serovar Typhimurium><S. typhimurium><Salmonella enterica Typhimurium><Salmonella enterica serovar Typhimurium><Salmonella typhimurium><Scaffolding Protein><Series><Signal Transduction><Signal Transduction Systems><Signaling><Site><Structure><System><Tail><Techniques><Testing><Time><Transmission Electron Microscopy><Variant><Variation><Viral><Viral Coat Proteins><Viral Gene Products><Viral Gene Proteins><Viral Outer Coat Protein><Viral Proteins><Virion><Virus><Virus Assembly><Virus Particle><Wing><Work><anti-viral compound><anti-viral drugs><anti-viral medication><anti-viral therapeutic><anti-virals><bacterial virus><biological signal transduction><bound protein><conformation><conformational><conformational state><conformationally><conformations><cryo-EM><cryoEM><cryogenic electron microscopy><developmental><drug development><ds-DNA><dsDNA><dsDNA Virus><experiment><experimental research><experimental study><experiments><herpes virus><human pathogen><in vivo><innovate><innovation><innovative><monomer><novel><pathway><protein complex><protein protein interaction><resolutions><social role><terminase><viral assembly><virus protein>