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Conformational Ensembles from Experimental Data
and Computer Simulations
Poster Abstracts
134
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.