22nd Annual Student Research Conference
The Bacteriophage λ DNA Packaging Motor: A Genetic Analysis of Reversion Mutations of Lethal Terminase Packaging Defects
Dan W. Serber
Dr. Michael Feiss (University of Iowa) and Dr. Diane Janick-Buckner, Faculty Mentors
The DNA packaging motor of bacteriophage λ is dependent on the functioning of the enzyme terminase. Terminase is responsible for binding and cutting the DNA concatemer and recruiting the phage prohead. The ATPase domain of the large subunit, gpA, translocates the DNA into the prohead. Mutations affecting the ATPase/packaging domain of gpA have been shown to cause lethal post-cleavage packaging defects. These λA− phages cannot grow lytically, but can be propagated as a prophage, and are copied along with the host genome. A λA− prophage is susceptible to random mutations, which may allow the virus to regain its genome packaging functions. Observed pseudo-reversion mutations, where the initial mutation was retained with another mutation elsewhere in gpA, were analyzed based on comparison to the crystal structure of the related T4 virus large subunit. This comparison revealed several possible ideas regarding the interaction of conserved sequences within the phage λ DNA packaging motor.
Keywords: Bacteriophage λ, Virus Assembly, Microbiology, Genetics
Topic(s):Biology
Presentation Type: Poster
Session: 10-8
Location: PML
Time: 4:15