Uridine as a new scavenger for synchrotron-based structural biology techniques

Macromolecular crystallography (MX) and small-angle X-ray scattering (SAXS) studies on proteins at synchrotron light sources are commonly limited by the structural damage produced by the intense X-ray beam. Several effects, such as aggregation in protein solutions and global and site-specific damage in crystals, reduce the data quality or even introduce artefacts that can result in a biologically misguiding structure. One strategy to reduce these negative effects is the inclusion of an additive in the buffer solution to act as a free radical scavenger. Here the properties of uridine as a scavenger for both SAXS and MX experiments on lysozyme at room temperature are examined. In MX experiments, upon addition of uridine at 1   M, the critical dose D1/2 is increased by a factor of ∼ 1.7, a value similar to that obtained in the presence of the most commonly used scavengers such as ascorbate and sodium nitrate. Other figures of merit to assess radiation damage show a similar trend. In SAXS experiments, the scavenging effect of 40   mM uridine is similar to that of 5% v/v glycerol, and greater than 2   mM DTT and 1   mM ascorbic acid. In all cases, the protective effect of uridine is proportional to its concentration.

Source: Journal of Synchrotron Radiation - December 16, 2016 Category: Physics Authors: Crosas, E. Castellvi, A. Crespo, I. Fulla, D. Gil-Ortiz, F. Fuertes, G. Kamma-Lorger, C.S. Malfois, M. Aranda, M.A.G. Juanhuix, J. Tags: radiation damage reactive oxygen species free radical scavenger macromolecular crystallography methods SAXS methods research papers Source Type: research