Polyphosphates diminish solubility of a globular protein and thereby promote amyloid aggregation

Structural changes of globular proteins and their resultant amyloid aggregation have been associated with various human diseases, such as lysozyme amyloidosis and light-chain amyloidosis. Because many globular proteins can convert into amyloid fibrils in vitro, the mechanisms of amyloid fibril formation have been studied in various experimental systems, but several questions remain unresolved. Here, using several approaches, such as turbidimetry, fluorescence and CD spectroscopy, EM, and isothermal titration calorimetry, we examined the binding of polyphosphates to hen egg-white lysozyme under acidic conditions and observed polyphosphate-induced structural changes of the protein promoting its aggregation. Our data indicate that negatively charged polyphosphates bind to protein molecules with a net positive charge. The polyphosphate-bound, structurally destabilized protein molecules then start assembling into insoluble amorphous aggregates once they pass the solubility limit. We further show that the polyphosphates decrease the solubility limit of the protein and near this limit, the protein molecules are in a labile state and highly prone to converting into amyloid fibrils. Our results explain how polyphosphates affect amorphous aggregation of proteins, how amyloid formation is induced in the presence of polyphosphates, and how polyphosphate chain length is an important factor in amyloid formation.

[1]  I. Narita,et al.  Possible mechanisms of polyphosphate-induced amyloid fibril formation of β2-microglobulin , 2019, Proceedings of the National Academy of Sciences.

[2]  J. Kardos,et al.  Aggregation-phase diagrams of β2-microglobulin reveal temperature and salt effects on competitive formation of amyloids versus amorphous aggregates , 2018, The Journal of Biological Chemistry.

[3]  Huan‐Xiang Zhou,et al.  Electrostatic Interactions in Protein Structure, Folding, Binding, and Condensation. , 2018, Chemical reviews.

[4]  Y. Kuroda.  Biophysical studies of protein solubility and amorphous aggregation by systematic mutational analysis and a helical polymerization model , 2018, Biophysical Reviews.

[5]  H. Ogi,et al.  Heparin-dependent aggregation of hen egg white lysozyme reveals two distinct mechanisms of amyloid fibrillation , 2017, The Journal of Biological Chemistry.

[6]  R. Mezzenga,et al.  Implications of peptide assemblies in amyloid diseases. , 2017, Chemical Society reviews.

[7]  S. Auer.  Simple Model of the Effect of Solution Conditions on the Nucleation of Amyloid Fibrils. , 2017, The journal of physical chemistry. B.

[8]  C. Dobson,et al.  Protein Misfolding, Amyloid Formation, and Human Disease: A Summary of Progress Over the Last Decade. , 2017, Annual review of biochemistry.

[9]  A. Gronenborn,et al.  Cataract-associated P23T γD-crystallin retains a native-like fold in amorphous-looking aggregates formed at physiological pH , 2017, Nature Communications.

[10]  Roland Riek,et al.  The activities of amyloids from a structural perspective , 2016, Nature.

[11]  M. Chapman,et al.  Polyphosphate: A Conserved Modifier of Amyloidogenic Processes. , 2016, Molecular cell.

[12]  D. Hall,et al.  Revisiting supersaturation as a factor determining amyloid fibrillation. , 2016, Current opinion in structural biology.

[13]  A. Serrano,et al.  Inorganic polyphosphate in the microbial world. Emerging roles for a multifaceted biopolymer , 2016, World journal of microbiology & biotechnology.

[14]  J. Kardos,et al.  Supersaturation-limited and Unlimited Phase Transitions Compete to Produce the Pathway Complexity in Amyloid Fibrillation* , 2015, The Journal of Biological Chemistry.

[15]  Tuomas P. J. Knowles,et al.  On the lag phase in amyloid fibril formation , 2015, Physical chemistry chemical physics : PCCP.

[16]  C. Dobson,et al.  Supersaturation is a major driving force for protein aggregation in neurodegenerative diseases. , 2015, Trends in pharmacological sciences.

[17]  J. Schmit,et al.  Stable, Metastable, and Kinetically Trapped Amyloid Aggregate Phases , 2014, Biomacromolecules.

[18]  T. Ikegami,et al.  Heat of supersaturation-limited amyloid burst directly monitored by isothermal titration calorimetry , 2014, Proceedings of the National Academy of Sciences.

[19]  R. Bender,et al.  Polyphosphate is a primordial chaperone. , 2014, Molecular cell.

[20]  T. Danieli,et al.  Production of prone‐to‐aggregate proteins , 2014, FEBS letters.

[21]  C. Dobson,et al.  Widespread aggregation and neurodegenerative diseases are associated with supersaturated proteins. , 2013, Cell reports.

[22]  R. Falconer,et al.  Thermal stability of lysozyme as a function of ion concentration: A reappraisal of the relationship between the Hofmeister series and protein stability , 2013, Protein science : a publication of the Protein Society.

[23]  Hirotsugu Ogi,et al.  Distinguishing crystal-like amyloid fibrils and glass-like amorphous aggregates from their kinetics of formation , 2012, Proceedings of the National Academy of Sciences.

[24]  F. Chiti,et al.  Rapid oligomer formation of human muscle acylphosphatase induced by heparan sulfate , 2012, Nature Structural &Molecular Biology.

[25]  F. Chiti,et al.  Protein misfolded oligomers: experimental approaches, mechanism of formation, and structure-toxicity relationships. , 2012, Chemistry & biology.

[26]  S. Radford,et al.  A diversity of assembly mechanisms of a generic amyloid fold. , 2011, Molecular cell.

[27]  Changlin Liu,et al.  Nucleic acid-mediated protein aggregation and assembly. , 2011, Advances in protein chemistry and structural biology.

[28]  R. Swaminathan,et al.  Lysozyme: a model protein for amyloid research. , 2011, Advances in protein chemistry and structural biology.

[29]  P. Cremer,et al.  Chemistry of Hofmeister anions and osmolytes. , 2010, Annual review of physical chemistry.

[30]  F. Chiti,et al.  Amyloid formation by the model protein muscle acylphosphatase is accelerated by heparin and heparan sulphate through a scaffolding-based mechanism. , 2009, Journal of biochemistry.

[31]  C. Pace,et al.  Protein Ionizable Groups: pK Values and Their Contribution to Protein Stability and Solubility* , 2009, Journal of Biological Chemistry.

[32]  Fabrizio Chiti,et al.  Amyloid formation by globular proteins under native conditions. , 2009, Nature chemical biology.

[33]  F. Chiti,et al.  Amyloidogenesis in its biological environment: challenging a fundamental issue in protein misfolding diseases. , 2008, Current opinion in structural biology.

[34]  O. Annunziata,et al.  Solubility of lysozyme in the presence of aqueous chloride salts: common-ion effect and its role on solubility and crystal thermodynamics. , 2008, Journal of the American Chemical Society.

[35]  H. Naiki,et al.  Heat-induced Conversion of β2-Microglobulin and Hen Egg-white Lysozyme into Amyloid Fibrils , 2007 .

[36]  Fabrizio Chiti,et al.  Stabilization of a native protein mediated by ligand binding inhibits amyloid formation independently of the aggregation pathway. , 2006, Journal of medicinal chemistry.

[37]  C. Dobson,et al.  Nature and significance of the interactions between amyloid fibrils and biological polyelectrolytes. , 2006, Biochemistry.

[38]  A. Fink,et al.  Characterization of oligomers during alpha-synuclein aggregation using intrinsic tryptophan fluorescence. , 2006, Biochemistry.

[39]  S. Radford,et al.  Competing pathways determine fibril morphology in the self-assembly of beta2-microglobulin into amyloid. , 2005, Journal of molecular biology.

[40]  Biman Bagchi,et al.  Water dynamics in the hydration layer around proteins and micelles. , 2005, Chemical reviews.

[41]  Peter T Lansbury,et al.  Small-molecule-mediated stabilization of familial amyotrophic lateral sclerosis-linked superoxide dismutase mutants against unfolding and aggregation. , 2005, Proceedings of the National Academy of Sciences of the United States of America.

[42]  T. Ban,et al.  Critical balance of electrostatic and hydrophobic interactions is required for beta 2-microglobulin amyloid fibril growth and stability. , 2005, Biochemistry.

[43]  Christopher M. Dobson,et al.  A camelid antibody fragment inhibits the formation of amyloid fibrils by human lysozyme , 2003, Nature.

[44]  V. Uversky,et al.  Elucidation of the Molecular Mechanism during the Early Events in Immunoglobulin Light Chain Amyloid Fibrillation , 2002, The Journal of Biological Chemistry.

[45]  R. L. Baldwin,et al.  How Hofmeister ion interactions affect protein stability. , 1996, Biophysical journal.

[46]  A. Kornberg,et al.  Inorganic Polyphosphate in Mammalian Cells and Tissues (*) , 1995, The Journal of Biological Chemistry.

[47]  T. Arakawa,et al.  Preferential interactions of proteins with salts in concentrated solutions. , 1982, Biochemistry.