TY - JOUR

T1 - Global fitting of multiple data frames from SEC-SAXS to investigate the structure of next-generation nanodiscs

AU - Barclay, Abigail

AU - Johansen, Nicolai Tidemand

AU - Tidemand, Frederik Grønbæk

AU - Arleth, Lise

AU - Pedersen, Martin Cramer

PY - 2022

Y1 - 2022

N2 - The combination of online size-exclusion chromatography and small-angle X-ray scattering (SEC-SAXS) is rapidly becoming a key technique for structural investigations of elaborate biophysical samples in solution. Here, a novel model-refinement strategy centred around the technique is outlined and its utility is demonstrated by analysing data series from several SEC-SAXS experiments on phospholipid bilayer nanodiscs. Using this method, a single model was globally refined against many frames from the same data series, thereby capturing the frame-to-frame tendencies of the irradiated sample. These are compared with models refined in the traditional manner, in which refinement is based on the average profile of a set of consecutive frames from the same data series without an in-depth comparison of individual frames. This is considered to be an attractive model-refinement scheme as it considerably lowers the total number of parameters refined from the data series, produces tendencies that are automatically consistent between frames, and utilizes a considerably larger portion of the recorded data than is often performed in such experiments. Additionally, a method is outlined for correcting a measured UV absorption signal by accounting for potential peak broadening by the experimental setup.

AB - The combination of online size-exclusion chromatography and small-angle X-ray scattering (SEC-SAXS) is rapidly becoming a key technique for structural investigations of elaborate biophysical samples in solution. Here, a novel model-refinement strategy centred around the technique is outlined and its utility is demonstrated by analysing data series from several SEC-SAXS experiments on phospholipid bilayer nanodiscs. Using this method, a single model was globally refined against many frames from the same data series, thereby capturing the frame-to-frame tendencies of the irradiated sample. These are compared with models refined in the traditional manner, in which refinement is based on the average profile of a set of consecutive frames from the same data series without an in-depth comparison of individual frames. This is considered to be an attractive model-refinement scheme as it considerably lowers the total number of parameters refined from the data series, produces tendencies that are automatically consistent between frames, and utilizes a considerably larger portion of the recorded data than is often performed in such experiments. Additionally, a method is outlined for correcting a measured UV absorption signal by accounting for potential peak broadening by the experimental setup.

KW - small-angle scattering

KW - size-exclusion chromatography

KW - phospholipid nanodiscs

KW - model refinement

KW - ANGLE X-RAY

KW - PHOSPHOLIPID-BILAYER NANODISCS

KW - SCATTERING DATA

KW - NEUTRON-SCATTERING

KW - MEMBRANE-PROTEINS

KW - COMPLEX

KW - NANOPARTICLES

KW - DYNAMICS

KW - SYSTEMS

KW - MODEL

U2 - 10.1107/S2059798322001838

DO - 10.1107/S2059798322001838

M3 - Journal article

C2 - 35362471

VL - 78

SP - 483

EP - 493

JO - Acta Crystallographica Section D: Biological Crystallography

JF - Acta Crystallographica Section D: Biological Crystallography

SN - 2059-7983

ER -