Structural dynamics of IDR interactions in human SFPQ and implications for liquid–liquid phase separation

Koning H, Lai V, Sethi A, Chakraborty S, Ang C, Fox A, Duff A, Whitten A, Marshall A, Bond C
Acta Crystallographica Section D Structural Biology 81(7):357-379 (2025 Jun 27)

doi: 10.1107/S2059798325005303

Submitted to SASBDB: 2024 Sep 18 Published in SASBDB: 2025 Jun 29

SASDXD4 – Full-length human SFPQ dimer (protiated and deuterated) Sample: Splicing factor, proline- and glutamine-rich dimer, 153 kDa Homo sapiens protein Buffer: 150 mM KCl, 1.5% glycerol, 20 mM HEPES, 1 mM DTT (in 100% H2O), pH: 7.4 Experiment: SANS data collected at Quokka - Small Angle Neutron Scattering, Australian Centre for Neutron Scattering (ANSTO) on 2023 Jan 23 RgGuinier 8.7 nm Dmax 30.7 nm VolumePorod 241000 nm3

SASDV57 – Full-length SFPQ in high salt buffer Sample: Splicing factor, proline- and glutamine-rich dimer, 153 kDa Homo sapiens protein Buffer: 500mM KNO3, 20mM HEPES, 5% glycerol, 1mM DTT, pH: 7.4 Experiment: SAXS data collected at SAXS/WAXS, Australian Synchrotron on 2022 Oct 22 RgGuinier 7.9 nm Dmax 42.5 nm VolumePorod 485 nm3

SASDV67 – Human Splicing Factor Proline/Glutamine rich SFPQ1 dimer with C-terminal truncation (delta599-707) Sample: Splicing Factor Proline/Glutamine rich (1-598) dimer, 130 kDa Homo sapiens protein Buffer: 500mM KNO3, 20mM HEPES, 5% glycerol, 1mM DTT, pH: 7.4 Experiment: SAXS data collected at SAXS/WAXS, Australian Synchrotron on 2023 Mar 13 RgGuinier 7.6 nm Dmax 34.3 nm VolumePorod 400 nm3

SASDV77 – Human Splicing Factor Proline/Glutamine rich SFPQ1 dimer with C-terminal truncation (delta599-707) in low salt buffer Sample: Splicing Factor Proline/Glutamine rich (1-598) dimer, 130 kDa Homo sapiens protein Buffer: 150 mM KCl, 20 mM HEPES, 5% glycerol, 5 mM MgCl2, 1 mM DTT, pH: 7.5 Experiment: SAXS data collected at SAXS/WAXS, Australian Synchrotron on 2023 Mar 13 RgGuinier 6.1 nm Dmax 28.0 nm VolumePorod 315 nm3

SASDV59 – Human Splicing factor, proline- and glutamine-rich protein 5% SFPQ and 95% dSFPQ at a D2O matchpoint of 95% Sample: Splicing factor, proline- and glutamine-rich dimer, 153 kDa Homo sapiens protein Buffer: 150 mM KCl, 0.075% glycerol, 20 mM HEPES, 0.5 mM DTT,, pH: 7.4 Experiment: SANS data collected at Quokka - Small Angle Neutron Scattering, Australian Centre for Neutron Scattering (ANSTO) on 2023 Jan 20 RgGuinier 6.1 nm Dmax 22.0 nm VolumePorod 181 nm3