Conformational Ensembles from Experimental Data and Computer Simulations

Conformational Ensembles from Experimental Data and Computer Simulations

Poster Abstracts

97-POS Board 17 Preferred Conformational States of Retroviral Capsid Protein Visualized Chun Tang , Wen-Xue Jiang, Xu Dong, Zhou Gong, Zhu Liu. Chinese Academy of Sciences, Wuhan, Hubei, China.

Discovered back in 1901, the Rous sarcoma virus (RSV) is a archetypal retrovirus. Several thousand copies of the RSV capsid (CA) protein interact with each other to form a nanoparticle with a variety of morphologies. A RSV CA comprises two domains, namely the N-terminal domain (NTD) and the C-terminal domain CTD, which are connected by a short linker. The previous cryoEM study has indicated that in the final CA assembly, specific interactions exist between the NTD and the CTD and between the CTD and the CTD from adjacent CA molecules. On the other hand, the previous NMR study has shown that the NTD and the CTD tumble independently in solution. To assess whether there is already any preference for the orientation between the two CA domains and to understand how CA molecules assemble to form an enclosed capsid, we carried out the study on the structure and dynamics of RSV CA protein, with conjoined use of single-molecule fluorescence resonance energy transfer (smFRET), small angle X-ray scattering, and NMR lanthanide pseudo-contact shift (PCS), which I will present at this meeting. We found that an RSV CA protein can exist in two alternative conformational states with the domains arranged differently. We call them the “up” and the “down” conformational states. Significantly, the “down” conformation can be dissipated at increasing concentration of the CA protein, while the “up” conformation closely resembles the CA structure found in RSV capsid assembly by cryoEM. As such, the preferred quaternary arrangements of the CA protein likely dictate the final outcome of the assembly product.

134