Derivation of the small‐angle scattering profile of a target biomacromolecule from a profile deteriorated by aggregates. AUC–SAS

• Published in: Journal of applied crystallography 2023-06, Vol.56 (3), p.624-632
• Main Authors: Morishima, Ken, Inoue, Rintaro, Sugiyama, Masaaki
• Format: Article
• Language: English
• Subjects: Aggregates; analytical ultracentrifugation; biomacromolecules; Molecular structure; Neutron scattering; protein solutions; Research Papers; small‐angle neutron scattering; small‐angle X‐ray scattering; Structural analysis; Ultracentrifugation
• ISSN: 1600-5767; 0021-8898; 1600-5767
• DOI: 10.1107/S1600576723002406

Aggregates cause a fatal problem in the structural analysis of a biomacromolecule in solution using small‐angle X‐ray or neutron scattering (SAS): they deteriorate the scattering profile of the target molecule and lead to an incorrect structure. Recently, an integrated method of analytical ultracentrifugation (AUC) and SAS, abbreviated AUC–SAS, was developed as a new approach to overcome this problem. However, the original version of AUC–SAS does not offer a correct scattering profile of the target molecule when the weight fraction of aggregates is higher than ca 10%. In this study, the obstacle point in the original AUC–SAS approach is identified. The improved AUC–SAS method is then applicable to a solution with a relatively larger weight fraction of aggregates (≤20%). An integrated method using analytical ultracentrifugation (AUC) and small‐angle scattering (SAS), AUC–SAS, has been developed for the structural analysis of a biomacromolecule in solution. In this study, the first version of AUC–SAS is improved upon so as to be applicable to a solution with a large number of aggregates.