Selective observation of semi-rigid non-core residues in dynamically complex mutant huntingtin protein fibrils
Many amyloid-forming proteins, which are normally intrinsically disordered, undergo a disorder-to-order transition to form fibrils with a rigid β-sheet core flanked by disordered domains. Solid-state NMR (ssNMR) and cryogenic electron microscopy (cryoEM) excel at resolving the rigid structures withi...
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| Format: | Article |
| Language: | English |
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Elsevier
2022-01-01
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| Series: | Journal of Structural Biology: X |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2590152422000186 |
| _version_ | 1811201777074176000 |
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| author | Irina Matlahov Jennifer C. Boatz Patrick C.A. van der Wel |
| author_facet | Irina Matlahov Jennifer C. Boatz Patrick C.A. van der Wel |
| author_sort | Irina Matlahov |
| collection | DOAJ |
| description | Many amyloid-forming proteins, which are normally intrinsically disordered, undergo a disorder-to-order transition to form fibrils with a rigid β-sheet core flanked by disordered domains. Solid-state NMR (ssNMR) and cryogenic electron microscopy (cryoEM) excel at resolving the rigid structures within amyloid cores but studying the dynamically disordered domains remains challenging. This challenge is exemplified by mutant huntingtin exon 1 (HttEx1), which self-assembles into pathogenic neuronal inclusions in Huntington disease (HD). The mutant protein’s expanded polyglutamine (polyQ) segment forms a fibril core that is rigid and sequestered from the solvent. Beyond the core, solvent-exposed surface residues mediate biological interactions and other properties of fibril polymorphs. Here we deploy magic angle spinning ssNMR experiments to probe for semi-rigid residues proximal to the fibril core and examine how solvent dynamics impact the fibrils’ segmental dynamics. Dynamic spectral editing (DYSE) 2D ssNMR based on a combination of cross-polarization (CP) ssNMR with selective dipolar dephasing reveals the weak signals of solvent-mobilized glutamine residues, while suppressing the normally strong background of rigid core signals. This type of ‘intermediate motion selection’ (IMS) experiment based on cross-polarization (CP) ssNMR, is complementary to INEPT- and CP-based measurements that highlight highly flexible or highly rigid protein segments, respectively. Integration of the IMS-DYSE element in standard CP-based ssNMR experiments permits the observation of semi-rigid residues in a variety of contexts, including in membrane proteins and protein complexes. We discuss the relevance of semi-rigid solvent-facing residues outside the fibril core to the latter’s detection with specific dyes and positron emission tomography tracers. |
| first_indexed | 2024-04-12T02:27:39Z |
| format | Article |
| id | doaj.art-4d3e78de81b94d97bfd332cdf1d21eff |
| institution | Directory Open Access Journal |
| issn | 2590-1524 |
| language | English |
| last_indexed | 2024-04-12T02:27:39Z |
| publishDate | 2022-01-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Journal of Structural Biology: X |
| spelling | doaj.art-4d3e78de81b94d97bfd332cdf1d21eff2022-12-22T03:51:55ZengElsevierJournal of Structural Biology: X2590-15242022-01-016100077Selective observation of semi-rigid non-core residues in dynamically complex mutant huntingtin protein fibrilsIrina Matlahov0Jennifer C. Boatz1Patrick C.A. van der Wel2Zernike Institute for Advanced Materials, University of Groningen, Groningen, The NetherlandsDepartment of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USAZernike Institute for Advanced Materials, University of Groningen, Groningen, The Netherlands; Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA; Corresponding author at: Nijenborgh 4, 9747AG Groningen, The Netherlands.Many amyloid-forming proteins, which are normally intrinsically disordered, undergo a disorder-to-order transition to form fibrils with a rigid β-sheet core flanked by disordered domains. Solid-state NMR (ssNMR) and cryogenic electron microscopy (cryoEM) excel at resolving the rigid structures within amyloid cores but studying the dynamically disordered domains remains challenging. This challenge is exemplified by mutant huntingtin exon 1 (HttEx1), which self-assembles into pathogenic neuronal inclusions in Huntington disease (HD). The mutant protein’s expanded polyglutamine (polyQ) segment forms a fibril core that is rigid and sequestered from the solvent. Beyond the core, solvent-exposed surface residues mediate biological interactions and other properties of fibril polymorphs. Here we deploy magic angle spinning ssNMR experiments to probe for semi-rigid residues proximal to the fibril core and examine how solvent dynamics impact the fibrils’ segmental dynamics. Dynamic spectral editing (DYSE) 2D ssNMR based on a combination of cross-polarization (CP) ssNMR with selective dipolar dephasing reveals the weak signals of solvent-mobilized glutamine residues, while suppressing the normally strong background of rigid core signals. This type of ‘intermediate motion selection’ (IMS) experiment based on cross-polarization (CP) ssNMR, is complementary to INEPT- and CP-based measurements that highlight highly flexible or highly rigid protein segments, respectively. Integration of the IMS-DYSE element in standard CP-based ssNMR experiments permits the observation of semi-rigid residues in a variety of contexts, including in membrane proteins and protein complexes. We discuss the relevance of semi-rigid solvent-facing residues outside the fibril core to the latter’s detection with specific dyes and positron emission tomography tracers.http://www.sciencedirect.com/science/article/pii/S2590152422000186Intermediate-timescale motionSolid state NMRHuntington’s diseasePolyglutamineDynamics |
| spellingShingle | Irina Matlahov Jennifer C. Boatz Patrick C.A. van der Wel Selective observation of semi-rigid non-core residues in dynamically complex mutant huntingtin protein fibrils Journal of Structural Biology: X Intermediate-timescale motion Solid state NMR Huntington’s disease Polyglutamine Dynamics |
| title | Selective observation of semi-rigid non-core residues in dynamically complex mutant huntingtin protein fibrils |
| title_full | Selective observation of semi-rigid non-core residues in dynamically complex mutant huntingtin protein fibrils |
| title_fullStr | Selective observation of semi-rigid non-core residues in dynamically complex mutant huntingtin protein fibrils |
| title_full_unstemmed | Selective observation of semi-rigid non-core residues in dynamically complex mutant huntingtin protein fibrils |
| title_short | Selective observation of semi-rigid non-core residues in dynamically complex mutant huntingtin protein fibrils |
| title_sort | selective observation of semi rigid non core residues in dynamically complex mutant huntingtin protein fibrils |
| topic | Intermediate-timescale motion Solid state NMR Huntington’s disease Polyglutamine Dynamics |
| url | http://www.sciencedirect.com/science/article/pii/S2590152422000186 |
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