Direct measurement of Stokes-Einstein diffusion of Cowpea mosaic virus with 19 µs-resolved XPCS

Kacper Switalski; Jingyu Fan; Luxi Li; Miaoqi Chu; Erik Sarnello; Pete Jemian; Tao Li; Qian Wang; Qingteng Zhang

doi:10.1107/S1600577522008402

Direct measurement of Stokes-Einstein diffusion of Cowpea mosaic virus with 19 µs-resolved XPCS

J Synchrotron Radiat. 2022 Nov 1;29(Pt 6):1429-1435. doi: 10.1107/S1600577522008402. Epub 2022 Oct 10.

Authors

Kacper Switalski¹, Jingyu Fan², Luxi Li³, Miaoqi Chu³, Erik Sarnello⁴, Pete Jemian³, Tao Li⁴, Qian Wang², Qingteng Zhang³

Affiliations

¹ Department of Chemical Engineering, University of Illinois at Chicago, Chicago, IL 60611, USA.
² Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208, USA.
³ X-ray Science Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439, USA.
⁴ Department of Chemistry and Biochemistry, Northern Illinois University, DeKalb, IL 60115, USA.

Abstract

Brownian motion of Cowpea mosaic virus (CPMV) in water was measured using small-angle X-ray photon correlation spectroscopy (SA-XPCS) at 19.2 µs time resolution. It was found that the decorrelation time τ(Q) = 1/DQ² up to Q = 0.091 nm^-1. The hydrodynamic radius R_H determined from XPCS using Stokes-Einstein diffusion D = kT/(6πηR_H) is 43% larger than the geometric radius R₀ 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)₂SO₄, a possible effect of aggregation as well as slight variation of the structures of the capsid resulting from the salt-protein interactions.

Keywords: SAXS; XPCS; biomolecules; high-speed X-ray detectors; virus-like particles (VLPs).

open access.

MeSH terms

Capsid
Comovirus* / chemistry
Scattering, Small Angle
X-Ray Diffraction

Grants and funding

This research was performed at beamline 8-ID-I of the Advanced Photon Source, a US Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by ANL (contract No. DE-AC02-06CH11357). This work was supported in part by the US Department of Energy, Office of Science, Office of Workforce Development for Teachers and Scientists (WDTS) under the Science Undergraduate Laboratory Internships Program (SULI).