利用 19µs 分辨的 XPCS 直接测量豇豆花叶病毒的斯托克斯-爱因斯坦扩散。

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

机构信息

Department of Chemical Engineering, University of Illinois at Chicago, Chicago, IL 60611, USA.

Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208, USA.

出版信息

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

DOI:10.1107/S1600577522008402

PMID:36345751

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC9641563/

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/DQ up to Q = 0.091 nm. The hydrodynamic radius R determined from XPCS using Stokes-Einstein diffusion D = kT/(6πηR) is 43% larger than the geometric radius R determined from SAXS in the 0.007 M KPO buffer solution, whereas it is 80% larger for CPMV in 0.5 M NaCl and 104% larger in 0.5 M (NH)SO, a possible effect of aggregation as well as slight variation of the structures of the capsid resulting from the salt-protein interactions.

摘要

使用小角 X 射线光子相关光谱学（SA-XPCS）在 19.2 μs 的时间分辨率下测量了在水中的豇豆花叶病毒（CPMV）的布朗运动。结果发现，相关时间 τ(Q) = 1/DQ 直至 Q = 0.091nm。通过 XPCS 使用 Stokes-Einstein 扩散 D = kT/(6πηR) 确定的水动力半径 R 比在 0.007 M KPO 缓冲溶液中通过 SAXS 确定的几何半径 R 大 43%，而在 0.5 M NaCl 中 R 大 80%，在 0.5 M（NH）SO 中 R 大 104%，这可能是聚集的影响以及盐-蛋白相互作用导致衣壳结构的细微变化。