Book of Abstracts: Albany 2009
June 16-20 2009
© Adenine Press (2008)
Single molecule analysis of motors moving on RNA
We are using single molecule fluorescence techniques to monitor movements of molecular motors moving on RNA. First, I will present our recent finding that a cytosolic viral RNA sensor RIG-I (Retinoic acid-Inducible Gene 1) is a translocase on double stranded RNA. Its RNA translocation activity is severely inhibited by the N-terminal domains of RIG-I but is restored fully when RIG-I recognizes 5' triphosphate on the same RNA. Because double stranded RNA and 5' triphophates are viral signatures known to be recognized by RIG-I, our results suggest an integrated sensing mechanism that can be more specific to the viral RNA. In the second part of the talk, I will discuss the internal structural dynamics of ribosome during its translocation on mRNA. We found that the inter-subunit rotation of the ribosome which is believed to be a key feature of translocation once thought to be driven by elongation factor G is actually driven thermally. This suggests that ribosome is an inchworming Brownian ratchet and the parallels with helicase translocation mechanism will be discussed.
Department of Physics & Center for the Physics of Living Cells