1
|
Maya-Martinez R, Xu Y, Guthertz N, Walko M, Karamanos TK, Sobott F, Breeze AL, Radford SE. Dimers of D76N-β 2-microglobulin display potent antiamyloid aggregation activity. J Biol Chem 2022; 298:102659. [PMID: 36328246 PMCID: PMC9712992 DOI: 10.1016/j.jbc.2022.102659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 10/20/2022] [Accepted: 10/28/2022] [Indexed: 11/05/2022] Open
Abstract
Self-association of WT β2-microglobulin (WT-β2m) into amyloid fibrils is associated with the disorder dialysis related amyloidosis. In the familial variant D76N-β2m, the single amino acid substitution enhances the aggregation propensity of the protein dramatically and gives rise to a disorder that is independent of renal dysfunction. Numerous biophysical and structural studies on WT- and D76N-β2m have been performed in order to better understand the structure and dynamics of the native proteins and their different potentials to aggregate into amyloid. However, the structural properties of transient D76N-β2m oligomers and their role(s) in assembly remained uncharted. Here, we have utilized NMR methods, combined with photo-induced crosslinking, to detect, trap, and structurally characterize transient dimers of D76N-β2m. We show that the crosslinked D76N-β2m dimers have different structures from those previously characterized for the on-pathway dimers of ΔN6-β2m and are unable to assemble into amyloid. Instead, the crosslinked D76N-β2m dimers are potent inhibitors of amyloid formation, preventing primary nucleation and elongation/secondary nucleation when added in substoichiometric amounts with D76N-β2m monomers. The results highlight the specificity of early protein-protein interactions in amyloid formation and show how mapping these interfaces can inform new strategies to inhibit amyloid assembly.
Collapse
Affiliation(s)
- Roberto Maya-Martinez
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Yong Xu
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Nicolas Guthertz
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Martin Walko
- Astbury Centre for Structural Molecular Biology, School of Chemistry, University of Leeds, Leeds, United Kingdom
| | - Theodoros K Karamanos
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Frank Sobott
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Alexander L Breeze
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Sheena E Radford
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom.
| |
Collapse
|
2
|
Oliveira NFB, Rodrigues FEP, Vitorino JNM, Loureiro RJS, Faísca PFN, Machuqueiro M. Predicting stable binding modes from simulated dimers of the D76N mutant of β 2-microglobulin. Comput Struct Biotechnol J 2021; 19:5160-5169. [PMID: 34630936 PMCID: PMC8473664 DOI: 10.1016/j.csbj.2021.09.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 09/02/2021] [Accepted: 09/02/2021] [Indexed: 11/16/2022] Open
Abstract
β2m D76N mutant populates an aggregation-prone monomer (I2) with unstructured termini. MD and MM-PBSA indicate that I2 dimers are stabilized by hydrophobic interactions. The termini regions and BC- and DE-loops are prevalent in the most stable interfaces. The most stable dimer has a limited growth potential without structural rearrangement.
The D76N mutant of the β2m protein is a biologically motivated model system to study protein aggregation. There is strong experimental evidence, supported by molecular simulations, that D76N populates a highly dynamic conformation (which we originally named I2) that exposes aggregation-prone patches as a result of the detachment of the two terminal regions. Here, we use Molecular Dynamics simulations to study the stability of an ensemble of dimers of I2 generated via protein–protein docking. MM-PBSA calculations indicate that within the ensemble of investigated dimers the major contribution to interface stabilization at physiological pH comes from hydrophobic interactions between apolar residues. Our structural analysis also reveals that the interfacial region associated with the most stable binding modes are particularly rich in residues pertaining to both the N- and C-terminus, as well residues from the BC- and DE-loops. On the other hand, the less stable interfaces are stabilized by intermolecular interactions involving residues from the CD- and EF-loops. By focusing on the most stable binding modes, we used a simple geometric rule to propagate the corresponding dimer interfaces. We found that, in the absence of any kind of structural rearrangement occurring at an early stage of the oligomerization pathway, some interfaces drive a self-limited growth process, while others can be propagated indefinitely allowing the formation of long, polymerized chains. In particular, the interfacial region of the most stable binding mode reported here falls in the class of self-limited growth.
Collapse
Affiliation(s)
- Nuno F B Oliveira
- BioISI - Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, Campo Grande, C8 bdg, Lisboa 1749-016, Portugal.,Department of Chemistry and Biochemistry, Faculty of Sciences, University of Lisbon, Lisboa 1749-016, Portugal
| | - Filipe E P Rodrigues
- BioISI - Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, Campo Grande, C8 bdg, Lisboa 1749-016, Portugal.,Department of Chemistry and Biochemistry, Faculty of Sciences, University of Lisbon, Lisboa 1749-016, Portugal
| | - João N M Vitorino
- BioISI - Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, Campo Grande, C8 bdg, Lisboa 1749-016, Portugal.,Department of Chemistry and Biochemistry, Faculty of Sciences, University of Lisbon, Lisboa 1749-016, Portugal
| | - Rui J S Loureiro
- BioISI - Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, Campo Grande, C8 bdg, Lisboa 1749-016, Portugal
| | - Patrícia F N Faísca
- BioISI - Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, Campo Grande, C8 bdg, Lisboa 1749-016, Portugal.,Department of Physics, Faculty of Sciences, University of Lisbon, Lisbon 1749-016, Portugal
| | - Miguel Machuqueiro
- BioISI - Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, Campo Grande, C8 bdg, Lisboa 1749-016, Portugal.,Department of Chemistry and Biochemistry, Faculty of Sciences, University of Lisbon, Lisboa 1749-016, Portugal
| |
Collapse
|
3
|
Morand J, Nunes A, Faísca PFN. The folding space of protein β2-microglobulin is modulated by a single disulfide bridge. Phys Biol 2021; 18. [PMID: 34098544 DOI: 10.1088/1478-3975/ac08ec] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 06/07/2021] [Indexed: 11/11/2022]
Abstract
Protein beta-2-microglobulin (β2m) is classically considered the causative agent of dialysis related amyloidosis, a conformational disorder that affects patients undergoing long-term hemodialysis. The wild type (WT) form, the ΔN6 structural variant, and the D76N mutant have been extensively used as model systems ofβ2m aggregation. In all of them, the native structure is stabilized by a disulfide bridge between the sulphur atoms of the cysteine residues 25 (at B strand) and 80 (at F strand), which has been considered fundamental inβ2m fibrillogenesis. Here, we use extensive discrete molecular dynamics simulations of a full atomistic structure-based model to explore the role of this disulfide bridge as a modulator of the folding space ofβ2m. In particular, by considering different models for the disulfide bridge, we explore the thermodynamics of the folding transition, and the formation of intermediate states that may have the potential to trigger the aggregation cascade. Our results show that the dissulfide bridge affects folding transition and folding thermodynamics of the considered model systems, although to different extents. In particular, when the interaction between the sulphur atoms is stabilized relative to the other intramolecular interactions, or even locked (i.e. permanently established), the WT form populates an intermediate state featuring a well preserved core and two unstructured termini, which was previously detected only for the D76N mutant. The formation of this intermediate state may have important implications in our understanding ofβ2m fibrillogenesis.
Collapse
Affiliation(s)
- Jules Morand
- Departamento de Física and BioISI - Biosystems and Integrative Sciences Institute, Faculdade de Ciências, Universidade de Lisboa, CampoGrande, Ed. C8, 1749-016 Lisboa, Portugal
| | - Ana Nunes
- Departamento de Física and BioISI - Biosystems and Integrative Sciences Institute, Faculdade de Ciências, Universidade de Lisboa, CampoGrande, Ed. C8, 1749-016 Lisboa, Portugal
| | - Patrícia F N Faísca
- Departamento de Física and BioISI - Biosystems and Integrative Sciences Institute, Faculdade de Ciências, Universidade de Lisboa, CampoGrande, Ed. C8, 1749-016 Lisboa, Portugal
| |
Collapse
|
4
|
Li Y, Mohanty S, Nilsson D, Hansson B, Mao K, Irbäck A. When a foreign gene meets its native counterpart: computational biophysics analysis of two PgiC loci in the grass Festuca ovina. Sci Rep 2020; 10:18752. [PMID: 33127989 PMCID: PMC7599235 DOI: 10.1038/s41598-020-75650-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 10/16/2020] [Indexed: 11/14/2022] Open
Abstract
Duplicative horizontal gene transfer may bring two previously separated homologous genes together, which may raise questions about the interplay between the gene products. One such gene pair is the “native” PgiC1 and “foreign” PgiC2 in the perennial grass Festuca ovina. Both PgiC1 and PgiC2 encode cytosolic phosphoglucose isomerase, a dimeric enzyme whose proper binding is functionally essential. Here, we use biophysical simulations to explore the inter-monomer binding of the two homodimers and the heterodimer that can be produced by PgiC1 and PgiC2 in F. ovina. Using simulated native-state ensembles, we examine the structural properties and binding tightness of the dimers. In addition, we investigate their ability to withstand dissociation when pulled by a force. Our results suggest that the inter-monomer binding is tighter in the PgiC2 than the PgiC1 homodimer, which could explain the more frequent occurrence of the foreign PgiC2 homodimer in dry habitats. We further find that the PgiC1 and PgiC2 monomers are compatible with heterodimer formation; the computed binding tightness is comparable to that of the PgiC1 homodimer. Enhanced homodimer stability and capability of heterodimer formation with PgiC1 are properties of PgiC2 that may contribute to the retaining of the otherwise redundant PgiC2 gene.
Collapse
Affiliation(s)
- Yuan Li
- Computational Biology and Biological Physics, Department of Astronomy and Theoretical Physics, Lund University, 223 62, Lund, Sweden
| | - Sandipan Mohanty
- Institute for Advanced Simulation, Jülich Supercomputing Centre, Forschungszentrum Jülich, 52425, Jülich, Germany
| | - Daniel Nilsson
- Computational Biology and Biological Physics, Department of Astronomy and Theoretical Physics, Lund University, 223 62, Lund, Sweden
| | - Bengt Hansson
- Department of Biology, Lund University, 223 62, Lund, Sweden
| | - Kangshan Mao
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, 610065, China
| | - Anders Irbäck
- Computational Biology and Biological Physics, Department of Astronomy and Theoretical Physics, Lund University, 223 62, Lund, Sweden.
| |
Collapse
|
5
|
Childers MC, Daggett V. Edge Strand Dissociation and Conformational Changes in Transthyretin under Amyloidogenic Conditions. Biophys J 2020; 119:1995-2009. [PMID: 33091379 DOI: 10.1016/j.bpj.2020.08.043] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 08/09/2020] [Accepted: 08/31/2020] [Indexed: 01/18/2023] Open
Abstract
During amyloidogenesis, proteins undergo conformational changes that allow them to aggregate and assemble into insoluble, fibrillar structures. Soluble oligomers that form during this process typically contain 2-24 monomeric subunits and are cytotoxic. Before the formation of these soluble oligomers, monomeric species first adopt aggregation-competent conformations. Knowledge of the structures of these intermediate states is invaluable to the development of molecular strategies to arrest pathological amyloid aggregation. However, the highly dynamic and interconverting nature of amyloidogenic species limits biophysical characterization of their structures during amyloidogenesis. Here, we use molecular dynamics simulations to probe conformations sampled by monomeric transthyretin under amyloidogenic conditions. We show that certain β-strands in transthyretin tend to unfold and sample nonnative conformations and that the edge strands in one β-sheet (the DAGH sheet) are particularly susceptible to conformational changes in the monomeric state. We also find that changes in the tertiary structure of transthyretin can be associated with disruptions to the secondary structure. We evaluated the conformations produced by molecular dynamics by calculating how well molecular-dynamics-derived structures reproduced NMR-derived interatomic distances. Finally, we leverage our computational results to produce experimentally testable hypotheses that may aid experimental explorations of pathological conformations of transthyretin.
Collapse
Affiliation(s)
- Matthew C Childers
- Department of Bioengineering, University of Washington, Seattle, Washington.
| | - Valerie Daggett
- Department of Bioengineering, University of Washington, Seattle, Washington
| |
Collapse
|
6
|
Loureiro RJS, Faísca PFN. The Early Phase of β2-Microglobulin Aggregation: Perspectives From Molecular Simulations. Front Mol Biosci 2020; 7:578433. [PMID: 33134317 PMCID: PMC7550760 DOI: 10.3389/fmolb.2020.578433] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 09/08/2020] [Indexed: 11/24/2022] Open
Abstract
Protein β2-microglobulin is the causing agent of two amyloidosis, dialysis related amyloidosis (DRA), affecting the bones and cartilages of individuals with chronic renal failure undergoing long-term hemodialysis, and a systemic amyloidosis, found in one French family, which impairs visceral organs. The protein’s small size and its biomedical significance attracted the attention of theoretical scientists, and there are now several studies addressing its aggregation mechanism in the context of molecular simulations. Here, we review the early phase of β2-microglobulin aggregation, by focusing on the identification and structural characterization of monomers with the ability to trigger aggregation, and initial small oligomers (dimers, tetramers, hexamers etc.) formed in the so-called nucleation phase. We focus our analysis on results from molecular simulations and integrate our views with those coming from in vitro experiments to provide a broader perspective of this interesting field of research. We also outline directions for future computer simulation studies.
Collapse
Affiliation(s)
- Rui J S Loureiro
- Faculty of Sciences, BioISI - Biosystems & Integrative Sciences Institute, University of Lisboa, Lisbon, Portugal
| | - Patrícia F N Faísca
- Faculty of Sciences, BioISI - Biosystems & Integrative Sciences Institute, University of Lisboa, Lisbon, Portugal.,Department of Physics, Faculty of Sciences, University of Lisboa, Lisbon, Portugal
| |
Collapse
|
7
|
Smith HI, Guthertz N, Cawood EE, Maya-Martinez R, Breeze AL, Radford SE. The role of the I T-state in D76N β 2-microglobulin amyloid assembly: A crucial intermediate or an innocuous bystander? J Biol Chem 2020; 295:12474-12484. [PMID: 32661194 PMCID: PMC7458819 DOI: 10.1074/jbc.ra120.014901] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 07/06/2020] [Indexed: 02/05/2023] Open
Abstract
The D76N variant of human β2-microglobulin (β2m) is the causative agent of a hereditary amyloid disease. Interestingly, D76N-associated amyloidosis has a distinctive pathology compared with aggregation of WT-β2m, which occurs in dialysis-related amyloidosis. A folding intermediate of WT-β2m, known as the IT-state, which contains a nonnative trans Pro-32, has been shown to be a key precursor of WT-β2m aggregation in vitro. However, how a single amino acid substitution enhances the rate of aggregation of D76N-β2m and gives rise to a different amyloid disease remained unclear. Using real-time refolding experiments monitored by CD and NMR, we show that the folding mechanisms of WT- and D76N-β2m are conserved in that both proteins fold slowly via an IT-state that has similar structural properties. Surprisingly, however, direct measurement of the equilibrium population of IT using NMR showed no evidence for an increased population of the IT-state for D76N-β2m, ruling out previous models suggesting that this could explain its enhanced aggregation propensity. Producing a kinetically trapped analog of IT by deleting the N-terminal six amino acids increases the aggregation rate of WT-β2m but slows aggregation of D76N-β2m, supporting the view that although the folding mechanisms of the two proteins are conserved, their aggregation mechanisms differ. The results exclude the IT-state as the origin of the rapid aggregation of D76N-β2m, suggesting that other nonnative states must cause its high aggregation rate. The results highlight how a single substitution at a solvent-exposed site can affect the mechanism of aggregation and the resulting disease.
Collapse
Affiliation(s)
- Hugh I Smith
- Astbury Centre for Structural Molecular Biology, School of Molecular & Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Nicolas Guthertz
- Astbury Centre for Structural Molecular Biology, School of Molecular & Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Emma E Cawood
- Astbury Centre for Structural Molecular Biology, School of Molecular & Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom.,School of Chemistry, University of Leeds, Leeds, United Kingdom
| | - Roberto Maya-Martinez
- Astbury Centre for Structural Molecular Biology, School of Molecular & Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Alexander L Breeze
- Astbury Centre for Structural Molecular Biology, School of Molecular & Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Sheena E Radford
- Astbury Centre for Structural Molecular Biology, School of Molecular & Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| |
Collapse
|