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Sarkar D, Saha S, Krishnamoorthy J, Bhunia A. Application of singular value decomposition analysis: Insights into the complex mechanisms of amyloidogenesis. Biophys Chem 2024; 306:107157. [PMID: 38184980 DOI: 10.1016/j.bpc.2023.107157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 12/12/2023] [Accepted: 12/21/2023] [Indexed: 01/09/2024]
Abstract
Amyloidogenesis, with its multifaceted nature spanning from peptide self-assembly to membrane-mediated structural transitions, presents a significant challenge for the interdisciplinary scientific community. Here, we emphasize on how Singular Value Decomposition (SVD) can be employed to reveal hidden patterns and dominant modes of interaction that govern the complex process of amyloidogenesis. We first utilize SVD analysis on Circular Dichroism (CD) spectral datasets to identify the intermediate structural species emerging during peptide-membrane interactions and to determine binding constants more precisely than conventional methods. We investigate the monomer loss kinetics associated with peptide self-assembly using Nuclear Magnetic Resonance (NMR) dataset and determine the global kinetic parameters through SVD. Furthermore, we explore the seeded growth of amyloid fibrils by analyzing a time-dependent NMR dataset, shedding light on the kinetic intricacies of this process. Our analysis uncovers two distinct states in the aggregation of Aβ40 and pinpoints key residues responsible for this seeded growth. To strengthen our findings and enhance their robustness, we validate those using simulated data, thereby highlighting the physical interpretations derived from SVD. Overall, SVD analysis offers a model-free, global kinetic perspective, enabling the selection of optimal kinetic models. This study not only contributes valuable insights into the dynamics but also highlights the versatility of SVD in unravelling complex processes of amyloidogenesis.
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Affiliation(s)
- Dibakar Sarkar
- Department of Chemical Sciences, Bose Institute, Unified Academic Campus, Salt Lake, Sector V, Kolkata 700 091, India
| | - Sudipto Saha
- Department of Biological Sciences, Bose Institute, Unified Academic Campus, Salt Lake, Sector V, Kolkata 700 091, India
| | | | - Anirban Bhunia
- Department of Chemical Sciences, Bose Institute, Unified Academic Campus, Salt Lake, Sector V, Kolkata 700 091, India.
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Roy D, Maity NC, Kumar S, Maity A, Ratha BN, Biswas R, Maiti NC, Mandal AK, Bhunia A. Modulatory role of copper on hIAPP aggregation and toxicity in presence of insulin. Int J Biol Macromol 2023; 241:124470. [PMID: 37088193 DOI: 10.1016/j.ijbiomac.2023.124470] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 03/24/2023] [Accepted: 04/12/2023] [Indexed: 04/25/2023]
Abstract
Aggregation of the human islets amyloid polypeptide, or hIAPP, is linked to β-cell death in type II diabetes mellitus (T2DM). Different pancreatic β-cell environmental variables such as pH, insulin and metal ions play a key role in controlling the hIAPP aggregation. Since insulin and hIAPP are co-secreted, it is known from numerous studies that insulin suppresses hIAPP fibrillation by preventing the initial dimerization process. On the other hand, zinc and copper each have an inhibitory impact on hIAPP fibrillation, but copper promotes the production of toxic oligomers. Interestingly, the insulin oligomeric equilibrium is controlled by the concentration of zinc ions when the effect of insulin and zinc has been tested together. Lower zinc concentrations cause the equilibrium to shift towards the monomer and dimer states of insulin, which bind to monomeric hIAPP and stop it from developing into a fibril. On the other hand, the combined effects of copper and insulin have not yet been done. In this study, we have demonstrated how the presence of copper affects hIAPP aggregation and the toxicity of the resultant conformers with or without insulin. For this purpose, we have used a set of biophysical techniques, including NMR, fluorescence, CD etc., in combination with AFM and cell cytotoxicity assay. In the presence and/or absence of insulin, copper induces hIAPP to form structurally distinct stable toxic oligomers, deterring the fibrillation process. More specifically, the oligomers generated in the presence of insulin have slightly higher toxicity than those formed in the absence of insulin. This research will increase our understanding of the combined modulatory effect of two β-cell environmental factors on hIAPP aggregation.
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Affiliation(s)
- Dipanwita Roy
- Department of Biophysics, Bose Institute, Unified Academic Campus, Salt Lake, Sctor V, Kolkata 700091, India
| | - Narayan Chandra Maity
- Chemical, Biological and Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, Sector-III, Salt Lake, Kolkata 700106, India
| | - Sourav Kumar
- Department of Biophysics, Bose Institute, Unified Academic Campus, Salt Lake, Sctor V, Kolkata 700091, India
| | - Anupam Maity
- Structural Biology and Bioinformatics, CSIR-Indian Institute of Chemical Biology, 4 Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India
| | - Bhisma N Ratha
- Department of Biophysics, Bose Institute, Unified Academic Campus, Salt Lake, Sctor V, Kolkata 700091, India
| | - Ranjit Biswas
- Chemical, Biological and Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, Sector-III, Salt Lake, Kolkata 700106, India
| | - Nakul Chandra Maiti
- Structural Biology and Bioinformatics, CSIR-Indian Institute of Chemical Biology, 4 Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India
| | - Atin Kumar Mandal
- Division of Molecular Medicine, Bose Institute, Unified Academic Campus, Salt Lake, Sctor V, Kolkata, 700091, India
| | - Anirban Bhunia
- Department of Biophysics, Bose Institute, Unified Academic Campus, Salt Lake, Sctor V, Kolkata 700091, India.
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