SAXSMoW 3.0: New advances in the determination of the molecular weight of proteins in dilute solutions from SAXS intensity data on a relative scale

Mario de Oliveira Neto; Adriano de Freitas Fernandes; Vassili Piiadov; Aldo Felix Craievich; Evandro Ares de Araújo; Igor Polikarpov

doi:10.1002/pro.4227

SAXSMoW 3.0: New advances in the determination of the molecular weight of proteins in dilute solutions from SAXS intensity data on a relative scale

Protein Sci. 2022 Jan;31(1):251-258. doi: 10.1002/pro.4227. Epub 2021 Nov 18.

Authors

Mario de Oliveira Neto¹, Adriano de Freitas Fernandes², Vassili Piiadov², Aldo Felix Craievich³, Evandro Ares de Araújo⁴, Igor Polikarpov²

Affiliations

¹ Biophysics and Pharmacology Department, Bioscience Institute, Universidade Estadual Paulista, Botucatu, São Paulo, Brazil.
² Sao Carlos Institute of Physics, University of Sao Paulo, São Paulo, Brazil.
³ Department of Applied Physics, University of Sao Paulo, São Paulo, São Paulo, Brazil.
⁴ Brazilian Synchrotron Light Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, São Paulo, Brazil.

Abstract

SAXSMoW (SAXS Molecular Weight) is an online platform widely used over the past few years for determination of molecular weights of proteins in dilute solutions. The scattering intensity retrieved from small-angle X-ray scattering (SAXS) raw data is the sole input to SAXSMoW for determination of molecular weights of proteins in liquid. The current updated SAXSMoW version 3.0 determines the linear dependence of the true protein volume on their apparent protein volume, based on SAXS curves calculated for 67,000 protein structures selected from the Protein Data Bank. SAXSMoW 3.0 was tested against 43 experimental SAXS scattering curves from proteins with known molecular weights. Our results demonstrate that most of the molecular weights determined for the nonglycosylated and also for the glycosylated proteins are in good agreement with their expected molecular weights. Additionally, the average discrepancies between the calculated molecular weights and their nominal values for glycosylated proteins are similar to those for nonglycosylated ones.

Keywords: SAXS; molecular weight; protein density.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Databases, Protein*
Molecular Dynamics Simulation*
Molecular Weight
Proteins / chemistry*
Scattering, Small Angle*
Software*
X-Ray Diffraction*

Substances

Proteins