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Brownian motion of Cowpea mosaic virus (CPMV) in water was measured using small-angle X-ray photon correlation spectroscopy (SA-XPCS) at 19.2 mu s time resolution. It was found that the decorrelation time tau(Q) = 1/DQ(2) up to Q = 0.091 nm(-1). The hydrodynamic radius R-H determined from XPCS using Stokes-Einstein diffusion D = kT/(6 pi eta R-H) is 43% larger than the geometric radius R-0 determined from SAXS in the 0.007 M K3PO4 buffer solution, whereas it is 80% larger for CPMV in 0.5 M NaCl and 104% larger in 0.5 M (NH4)(2)SO4, a possible effect of aggregation as well as slight variation of the structures of the capsid resulting from the salt-protein interactions.

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APA Citation

Switalski, K., Fan, J., Li, L., Chu, M., Sarnello, E., Jemian, P. R., Li, T., Wang, Q., & Zhang, Q. (2022). Direct measurement of Stokes–Einstein diffusion of Cowpea mosaic virus with 19 µs-resolved XPCS. Journal of Synchrotron Radiation, 29(6), 1429–1435.