The Importance of Protein Dynamics in the RNA dependent RNA polymerase of Poliovirus

Open Access
Welch, Jesse Lee
Graduate Program:
Master of Science
Document Type:
Master Thesis
Date of Defense:
March 21, 2011
Committee Members:
  • David D Boehr, Thesis Advisor
  • Poliovirus
  • RdRp
  • NMR
Positive strand RNA viruses, such as poliovirus, cause a wide range of health problems such as poliomyelitis, SARS, and hepatitis C1-5. The lifecycle of these viruses involves entry into the host cell by some form of receptor mediated endocytosis, translation of the viral RNA, replication of the viral RNA, construction of new virions, and eventually the destruction of the host cell6-14. This project focuses upon the RNA dependent RNA polymerase (RdRp) from poliovirus. Fidelity mutants, such as G64S, greatly influence the fidelity of this protein without any substantial change in structure32. In addition, molecular dynamics simulations show considerable amounts of correlated motion between residues, and these results all suggest the possibility of an internal amino acid network important for enzyme catalysis and regulation. Here we utilize NMR to investigate this network. Because the protein is large (~52kDa), selective labeling of the methionine residues is applied to give us regional probes. Changes to chemical shifts and peak intensities among numerous mutants provided a means of detecting structural and/or dynamic changes throughout the protein. These findings strongly support the existence of a dynamic network that is important for governing enzyme function and fidelity.