During viral infection many viruses use a conserved motor mechanism to package double-stranded DNA (dsDNA) into the viral capsid. These DNA packaging motors are required for infectivity, and operate as several individual subunits working together as a motor. The packaging motor of lambda bacteriophage will be studied using biochemical and biophysical techniques (SA I), characterizing packaging deficient mutant subunits of the packaging motor, and (SA 11), mixing mutant and wild-type subunits to form chimeric packaging motors, and characterizing DNA packing. Understanding the exact deficiencies in motor subunits, and how one to several subunits can poison a motor will provide insight into the way these subunits work together and communicate to the other parts of the motor. Knowledge of this communication improves our general understanding of viruses and viral infection and will characterize an ideal viral process that can be disrupted to abolish or limit viral infection. Relevance: Understanding the mechanism of DNA packaging in viruses will identify further drug targets which can be used in therapy in viruses such as the clinically relevant herpes groups. Furthermore, the understanding of DNA packaging motors, among the most powerful of the characterized biological motors, has direct applications in molecular motors as nanomachines.