Accuracy of molecular mass determination of proteins in solution by small-angle X-ray scattering

By E. Mylonas, Dmitri I. Svergun. 2007

362 citations recorded by the source corpus.

One of the most important overall parameters, which can be derived from small-angle X-ray scattering (SAXS) experiments on macromolecular solutions is the molecular mass (MM) of the solute. In particular, for a monodisperse protein solution, MM of the solute is calculated from the extrapolated scattering intensity at zero angle I(0). Assessing MM by SAXS provides valuable information about the oligomeric state and absence of unspecific aggregation in solution. The value of MM can either be estimated by comparison with a protein standard with a known MM or by determining the absolute scattering intensity using, e.g., water scattering. In both cases, knowledge about the solute concentration and about the partial specific volume of the protein is required. By measuring 13 well characterized globular proteins with MMs ranging from 13.7 to 669 kDa we analyze the sources of possible systematic deviations and assess the accuracy of MM determination using SAXS. The data indicate that all these proteins have approximately the same `effective' value of the partial specific volume of about 0.7425 cm3 g−1. It is shown that both inter-protein and water calibration can be used for molecular mass determination by SAXS and in most cases the errors do not exceed 10%.

Subfields: Materials Chemistry, Molecular Biology, Radiation

View Paper: https://www.semanticscholar.org/paper/f2c299d04391b630da990aa66883c27d28c64802

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Citations in the corpus

ATSAS 2.8: a comprehensive data analysis suite for small-angle scattering from macromolecular solutions (2017, methodology): “Alternatively, empirically determined average values may be applied (Mylonas & Svergun, 2007) if none of the other methods are applicable or available.”
BioXTAS RAW: improvements to a free open-source program for small-angle X-ray scattering data reduction and analysis (2017, methodology): “Having multiple methods is important, as molecular weight determination from SAXS profiles is typically only accurate to 10% (Mylonas & Svergun, 2007), and different sources of error will affect the different methods.”
SASfit: a tool for small-angle scattering data analysis using a library of analytical expressions (2015, methodology): “Its scattering intensity was converted to absolute scale using water as primary standard according to the procedure described by Orthaber et al. (2000) and was veriﬁed using a measurement of bovine serum albumin (Mylonas & Svergun, 2007).”
Determination of the molecular weight of proteins in solution from a single small-angle X-ray scattering measurement on a relative scale (2010, methodology): “Both methodologies yield the molecular weight of proteins with an error of about 10%, provided the solute concentration is measured with an accuracy of 5–10%, which might not always be straightforward (Mylonas & Svergun, 2007).”
New developments in the ATSAS program package for small-angle scattering data analysis (2012, neutral): “In some cases obtaining an estimate of c is difficult (e.g. for proteins containing few aromatic residues), and the typical accuracy of the MM determination in practice is about 10– 15% (Mylonas & Svergun, 2007).”
Robust, high-throughput solution structural analyses by small angle X-ray scattering (SAXS) (2009, methodology): “When ambiguous, we estimated the mass by the extrapolated intensity at zero scattering angl”