Comprehensive biophysical and structural profiling of alpha-actinin-2 variants reveals mechanistic diversity in hypertrophic cardiomyopathy.

Noureddine M, Mikolajek H, Cowieson N, Pinotsis N, Robinson P, Slater A, Redwood C, Loughna S, Denning C, Mohammed F, Gehmlich K
Nat Commun 17(1) (2026 Jul 21)

PMID: 42481460 doi: 10.1038/s41467-026-75392-z

Submitted to SASBDB: 2026 Mar 31 Published in SASBDB: 2026 May 14

SASDZJ4 – Alpha-actinin-2 (ACTN2) wild-type, SEC-SAXS (aggregate peak) Sample: Alpha-actinin-2 dimer, 208 kDa Homo sapiens protein Buffer: 20 mM HEPES, 150 mM NaCl, pH: 8 Experiment: SAXS data collected at B21, Diamond Light Source on 2024 May 13 RgGuinier 12.1 nm Dmax 40.6 nm

SASDZK4 – Alpha-actinin-2 (ACTN2) wild-type, SEC-SAXS (dimer peak) Sample: Alpha-actinin-2 dimer, 208 kDa Homo sapiens protein Buffer: 20 mM HEPES, 150 mM NaCl, pH: 8 Experiment: SAXS data collected at B21, Diamond Light Source on 2024 May 13 RgGuinier 11.9 nm Dmax 36.2 nm

SASDZL4 – ACTN2-R457C at 60 degrees (°C) using batch-mode SAXS Sample: Alpha-actinin-2 dimer, 208 kDa Homo sapiens protein Buffer: 20 mM HEPES, 150 mM NaCl, pH: 8 Experiment: SAXS data collected at B21, Diamond Light Source on 2024 May 13 RgGuinier 10.9 nm Dmax 37.0 nm

SASDZM4 – ACTN2-R457C at 53 degrees (°C) using batch-mode SAX Sample: Alpha-actinin-2 dimer, 208 kDa Homo sapiens protein Buffer: 20 mM HEPES, 150 mM NaCl, pH: 8 Experiment: SAXS data collected at B21, Diamond Light Source on 2024 May 13 RgGuinier 10.3 nm Dmax 35.3 nm

SASDZN4 – ACTN2-R457C at 40 degrees (°C) using batch-mode SAXS Sample: Alpha-actinin-2 dimer, 208 kDa Homo sapiens protein Buffer: 20 mM HEPES, 150 mM NaCl, pH: 8 Experiment: SAXS data collected at B21, Diamond Light Source on 2024 May 13 RgGuinier 10.3 nm Dmax 37.0 nm

SASDZP4 – ACTN2-E448A at 60 degrees (°C) using batch-mode SAXS Sample: Alpha-actinin-2 dimer, 208 kDa Homo sapiens protein Buffer: 20 mM HEPES, 150 mM NaCl, pH: 8 Experiment: SAXS data collected at B21, Diamond Light Source on 2024 May 13 RgGuinier 10.9 nm Dmax 36.9 nm

SASDZQ4 – ACTN2-E448A at 53 degrees (°C) using batch-mode SAXS Sample: Alpha-actinin-2 dimer, 208 kDa Homo sapiens protein Buffer: 20 mM HEPES, 150 mM NaCl, pH: 8 Experiment: SAXS data collected at B21, Diamond Light Source on 2024 May 13 RgGuinier 10.6 nm Dmax 36.0 nm

SASDZR4 – ACTN2-E448A at 40 degrees (°C) using batch-mode SAXS Sample: Alpha-actinin-2 dimer, 208 kDa Homo sapiens protein Buffer: 20 mM HEPES, 150 mM NaCl, pH: 8 Experiment: SAXS data collected at B21, Diamond Light Source on 2024 May 13 RgGuinier 11.1 nm Dmax 38.0 nm

SASDZS4 – ACTN2-R327C at 60 degrees (°C) using batch-mode SAXS Sample: Alpha-actinin-2 dimer, 208 kDa Homo sapiens protein Buffer: 20 mM HEPES, 150 mM NaCl, pH: 8 Experiment: SAXS data collected at B21, Diamond Light Source on 2024 May 13 RgGuinier 10.7 nm Dmax 34.0 nm

SASDZT4 – ACTN2-R327C at 53 degrees (°C) using batch-mode SAXS Sample: Alpha-actinin-2 dimer, 208 kDa Homo sapiens protein Buffer: 20 mM HEPES, 150 mM NaCl, pH: 8 Experiment: SAXS data collected at B21, Diamond Light Source on 2024 May 13 RgGuinier 10.4 nm Dmax 36.0 nm

SASDZU4 – ACTN2-R327C at 40 degrees (°C) using batch-mode SAXS Sample: Alpha-actinin-2 dimer, 208 kDa Homo sapiens protein Buffer: 20 mM HEPES, 150 mM NaCl, pH: 8 Experiment: SAXS data collected at B21, Diamond Light Source on 2024 May 13 RgGuinier 11.4 nm Dmax 37.0 nm

SASDZV4 – ACTN2-T247M at 60 degrees (°C) using batch-mode SAXS Sample: Alpha-actinin-2 dimer, 208 kDa Homo sapiens protein Buffer: 20 mM HEPES, 150 mM NaCl, pH: 8 Experiment: SAXS data collected at B21, Diamond Light Source on 2024 May 13 RgGuinier 19.1 nm Dmax 70.2 nm

SASDZW4 – ACTN2-T247M at 53 degrees (°C) using batch-mode SAXS Sample: Alpha-actinin-2 dimer, 208 kDa Homo sapiens protein Buffer: 20 mM HEPES, 150 mM NaCl, pH: 8 Experiment: SAXS data collected at B21, Diamond Light Source on 2024 May 13 RgGuinier 17.0 nm Dmax 67.0 nm

SASDZX4 – ACTN2-T247M at 40 degrees (°C) using batch-mode SAXS Sample: Alpha-actinin-2 dimer, 208 kDa Homo sapiens protein Buffer: 20 mM HEPES, 150 mM NaCl, pH: 8 Experiment: SAXS data collected at B21, Diamond Light Source on 2024 May 13 RgGuinier 12.0 nm Dmax 37.9 nm

SASDZY4 – ACTN2-G111V at 60 degrees (°C) using batch-mode SAXS Sample: Alpha-actinin-2 dimer, 208 kDa Homo sapiens protein Buffer: 20 mM HEPES, 150 mM NaCl, pH: 8 Experiment: SAXS data collected at B21, Diamond Light Source on 2024 May 13 RgGuinier 17.9 nm Dmax 87.0 nm

SASDZZ4 – ACTN2-G111V at 53 degrees (°C) using batch-mode SAXS Sample: Alpha-actinin-2 dimer, 208 kDa Homo sapiens protein Buffer: 20 mM HEPES, 150 mM NaCl, pH: 8 Experiment: SAXS data collected at B21, Diamond Light Source on 2024 May 13 RgGuinier 13.9 nm Dmax 43.0 nm

SASDZ25 – ACTN2-G111V at 40 degrees (°C) using batch-mode SAXS Sample: Alpha-actinin-2 dimer, 208 kDa Homo sapiens protein Buffer: 20 mM HEPES, 150 mM NaCl, pH: 8 Experiment: SAXS data collected at B21, Diamond Light Source on 2024 May 13 RgGuinier 12.3 nm Dmax 38.6 nm

SASDZ35 – ACTN2-R93Q at 60 degrees (°C) using batch-mode SAXS Sample: Alpha-actinin-2 dimer, 208 kDa Homo sapiens protein Buffer: 20 mM HEPES, 150 mM NaCl, pH: 8 Experiment: SAXS data collected at B21, Diamond Light Source on 2024 May 13 RgGuinier 14.0 nm Dmax 49.3 nm

SASDZ45 – ACTN2-R93Q at 53 degrees (°C) using batch-mode SAXS Sample: Alpha-actinin-2 dimer, 208 kDa Homo sapiens protein Buffer: 20 mM HEPES, 150 mM NaCl, pH: 8 Experiment: SAXS data collected at B21, Diamond Light Source on 2024 May 13 RgGuinier 10.6 nm Dmax 36.0 nm

SASDZ55 – ACTN2-R93Q at 40 degrees (°C) using batch-mode SAXS Sample: Alpha-actinin-2 dimer, 208 kDa Homo sapiens protein Buffer: 20 mM HEPES, 150 mM NaCl, pH: 8 Experiment: SAXS data collected at B21, Diamond Light Source on 2024 May 13 RgGuinier 10.1 nm Dmax 37.1 nm

SASDZ65 – ACTN2-M92V at 60 degrees (°C) using batch-mode SAXS Sample: Alpha-actinin-2 dimer, 208 kDa Homo sapiens protein Buffer: 20 mM HEPES, 150 mM NaCl, pH: 8 Experiment: SAXS data collected at B21, Diamond Light Source on 2024 May 13 RgGuinier 13.5 nm Dmax 46.8 nm

SASDZ75 – ACTN2-M92V at 53 degrees (°C) using batch-mode SAXS Sample: Alpha-actinin-2 dimer, 208 kDa Homo sapiens protein Buffer: 20 mM HEPES, 150 mM NaCl, pH: 8 Experiment: SAXS data collected at B21, Diamond Light Source on 2024 May 13 RgGuinier 10.6 nm Dmax 35.0 nm

SASDZ85 – ACTN2-M92V at 40 degrees (°C) using batch-mode SAXS Sample: Alpha-actinin-2 dimer, 208 kDa Homo sapiens protein Buffer: 20 mM HEPES, 150 mM NaCl, pH: 8 Experiment: SAXS data collected at B21, Diamond Light Source on 2024 May 13 RgGuinier 10.6 nm Dmax 38.3 nm

SASDZ95 – Alpha-actinin-2 (ACTN2) wild-type at 60 °C Sample: Alpha-actinin-2 dimer, 208 kDa Homo sapiens protein Buffer: 20 mM HEPES, 150 mM NaCl, pH: 8 Experiment: SAXS data collected at B21, Diamond Light Source on 2024 May 13 RgGuinier 11.2 nm Dmax 37.0 nm

SASDZA5 – Alpha-actinin-2 (ACTN2) wild-type at 53 °C Sample: Alpha-actinin-2 dimer, 208 kDa Homo sapiens protein Buffer: 20 mM HEPES, 150 mM NaCl, pH: 8 Experiment: SAXS data collected at B21, Diamond Light Source on 2024 May 13 RgGuinier 10.4 nm Dmax 37.7 nm

SASDZB5 – Alpha-actinin-2 (ACTN2) wild-type at 40 °C Sample: Alpha-actinin-2 dimer, 208 kDa Homo sapiens protein Buffer: 20 mM HEPES, 150 mM NaCl, pH: 8 Experiment: SAXS data collected at B21, Diamond Light Source on 2024 May 13 RgGuinier 10.2 nm Dmax 37.6 nm

SASDZC5 – ACTN2-R457C using SEC-SAXS (dimer peak) Sample: Alpha-actinin-2 dimer, 208 kDa Homo sapiens protein Buffer: 20 mM HEPES, 150 mM NaCl, pH: 8 Experiment: SAXS data collected at B21, Diamond Light Source on 2024 May 13 RgGuinier 11.1 nm Dmax 37.0 nm

SASDZD5 – ACTN2-E448A using SEC-SAXS (dimer peak) Sample: Alpha-actinin-2 dimer, 208 kDa Homo sapiens protein Buffer: 20 mM HEPES, 150 mM NaCl, pH: 8 Experiment: SAXS data collected at B21, Diamond Light Source on 2024 May 13 RgGuinier 11.8 nm Dmax 36.5 nm

SASDZE5 – ACTN2-R457C using SEC-SAXS (aggregate peak) Sample: Alpha-actinin-2 dimer, 208 kDa Homo sapiens protein Buffer: 20 mM HEPES, 150 mM NaCl, pH: 8 Experiment: SAXS data collected at B21, Diamond Light Source on 2024 May 13 RgGuinier 12.8 nm Dmax 49.9 nm

SASDZF5 – ACTN2-E448A using SEC-SAXS (aggregate peak) Sample: Alpha-actinin-2 dimer, 208 kDa Homo sapiens protein Buffer: 20 mM HEPES, 150 mM NaCl, pH: 8 Experiment: SAXS data collected at B21, Diamond Light Source on 2024 May 13 RgGuinier 13.9 nm Dmax 48.1 nm

SASDZG5 – ACTN2-R327C using SEC-SAXS (dimer peak) Sample: Alpha-actinin-2 dimer, 208 kDa Homo sapiens protein Buffer: 20 mM HEPES, 150 mM NaCl, pH: 8 Experiment: SAXS data collected at B21, Diamond Light Source on 2024 May 13 RgGuinier 10.8 nm Dmax 36.1 nm

SASDZH5 – ACTN2-R327C using SEC-SAXS (aggregate peak) Sample: Alpha-actinin-2 dimer, 208 kDa Homo sapiens protein Buffer: 20 mM HEPES, 150 mM NaCl, pH: 8 Experiment: SAXS data collected at B21, Diamond Light Source on 2024 May 13 RgGuinier 12.8 nm Dmax 49.1 nm

SASDZJ5 – ACTN2-T247M using SEC-SAXS (dimer peak) Sample: Alpha-actinin-2 dimer, 208 kDa Homo sapiens protein Buffer: 20 mM HEPES, 150 mM NaCl, pH: 8 Experiment: SAXS data collected at B21, Diamond Light Source on 2024 May 13 RgGuinier 11.6 nm Dmax 37.0 nm

SASDZK5 – ACTN2-T247M using SEC-SAXS (aggregate peak) Sample: Alpha-actinin-2 dimer, 208 kDa Homo sapiens protein Buffer: 20 mM HEPES, 150 mM NaCl, pH: 8 Experiment: SAXS data collected at B21, Diamond Light Source on 2024 May 13 RgGuinier 16.1 nm Dmax 78.0 nm

SASDZL5 – ACTN2-G111V using SEC-SAXS (dimer peak) Sample: Alpha-actinin-2 dimer, 208 kDa Homo sapiens protein Buffer: 20 mM HEPES, 150 mM NaCl, pH: 8 Experiment: SAXS data collected at B21, Diamond Light Source on 2024 May 13 RgGuinier 10.4 nm Dmax 37.0 nm

SASDZM5 – ACTN2-G111V using SEC-SAXS (aggregate peak) Sample: Alpha-actinin-2 dimer, 208 kDa Homo sapiens protein Buffer: 20 mM HEPES, 150 mM NaCl, pH: 8 Experiment: SAXS data collected at B21, Diamond Light Source on 2024 May 13 RgGuinier 13.0 nm Dmax 55.5 nm

SASDZN5 – ACTN2-R93Q using SEC-SAXS (dimer peak) Sample: Alpha-actinin-2 dimer, 208 kDa Homo sapiens protein Buffer: 20 mM HEPES, 150 mM NaCl, pH: 8 Experiment: SAXS data collected at B21, Diamond Light Source on 2024 May 13 RgGuinier 11.6 nm Dmax 37.0 nm

SASDZP5 – ACTN2-R93Q using SEC-SAXS (aggregate peak) Sample: Alpha-actinin-2 dimer, 208 kDa Homo sapiens protein Buffer: 20 mM HEPES, 150 mM NaCl, pH: 8 Experiment: SAXS data collected at B21, Diamond Light Source on 2024 May 13 RgGuinier 12.9 nm Dmax 57.0 nm

SASDZQ5 – ACTN2-M92V using SEC-SAXS (dimer peak) Sample: Alpha-actinin-2 dimer, 208 kDa Homo sapiens protein Buffer: 20 mM HEPES, 150 mM NaCl, pH: 8 Experiment: SAXS data collected at B21, Diamond Light Source on 2024 May 13 RgGuinier 11.5 nm Dmax 36.1 nm

SASDZR5 – Alpha-actinin-2 (ACTN2) M92V variant, SEC-SAXS (aggregate peak) Sample: Alpha-actinin-2 dimer, 208 kDa Homo sapiens protein Buffer: 20 mM HEPES, 150 mM NaCl, pH: 8 Experiment: SAXS data collected at B21, Diamond Light Source on 2024 May 13 RgGuinier 11.6 nm Dmax 49.0 nm