Global structure of a three-way junction in a phi29 packaging RNA dimer determined using site-directed spin labeling.

ABSTRACT: The condensation of bacteriophage phi29 genomic DNA into its preformed procapsid requires the DNA packaging motor, which is the strongest known biological motor. The packaging motor is an intricate ring-shaped protein/RNA complex, and its function requires an RNA component called packaging RNA (pRNA). Current structural information on pRNA is limited, which hinders studies of motor function. Here, we used site-directed spin labeling to map the conformation of a pRNA three-way junction that bridges binding sites for the motor ATPase and the procapsid. The studies were carried out on a pRNA dimer, which is the simplest ring-shaped pRNA complex and serves as a functional intermediate during motor assembly. Using a nucleotide-independent labeling scheme, stable nitroxide radicals were attached

SUBMITTER: Zhang X 

PROVIDER: S-EPMC3279945 | biostudies-literature | 2012 Feb

REPOSITORIES: biostudies-literature