Ändra sökning
Länk till posten
Permanent länk

Direktlänk
Alternativa namn
Publikationer (10 of 158) Visa alla publikationer
Paul, S., Jenistova, A., Vosough, F., Berntsson, E., Mörman, C., Jarvet, J., . . . Barth, A. (2023). 13C- and 15N-labeling of amyloid-β and inhibitory peptides to study their interaction via nanoscale infrared spectroscopy. Communications Chemistry, 6(1), Article ID 163.
Öppna denna publikation i ny flik eller fönster >>13C- and 15N-labeling of amyloid-β and inhibitory peptides to study their interaction via nanoscale infrared spectroscopy
Visa övriga...
2023 (Engelska)Ingår i: Communications Chemistry, E-ISSN 2399-3669, Vol. 6, nr 1, artikel-id 163Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Interactions between molecules are fundamental in biology. They occur also between amyloidogenic peptides or proteins that are associated with different amyloid diseases, which makes it important to study the mutual influence of two polypeptides on each other's properties in mixed samples. However, addressing this research question with imaging techniques faces the challenge to distinguish different polypeptides without adding artificial probes for detection. Here, we show that nanoscale infrared spectroscopy in combination with C-13, N-15-labeling solves this problem. We studied aggregated amyloid-& beta; peptide (A & beta;) and its interaction with an inhibitory peptide (NCAM1-PrP) using scattering-type scanning near-field optical microscopy. Although having similar secondary structure, labeled and unlabeled peptides could be distinguished by comparing optical phase images taken at wavenumbers characteristic for either the labeled or the unlabeled peptide. NCAM1-PrP seems to be able to associate with or to dissolve existing A & beta; fibrils because pure A & beta; fibrils were not detected after mixing. Interactions of proteins or polypeptides with different secondary structures can be studied in a mixture by nanoscale infrared spectroscopy, however, this technique remains challenging for polypeptides with similar secondary structures. Here, the authors demonstrate clear discrimination of two polypeptides from a mixture by scattering-type scanning near-field optical microscopy when one of the components is labeled with C-13- and N-15-isotopes.

Nationell ämneskategori
Kemi Biokemi och molekylärbiologi
Identifikatorer
urn:nbn:se:su:diva-221129 (URN)10.1038/s42004-023-00955-w (DOI)001042052900001 ()37537303 (PubMedID)2-s2.0-85167397298 (Scopus ID)
Tillgänglig från: 2023-09-18 Skapad: 2023-09-18 Senast uppdaterad: 2023-09-18Bibliografiskt granskad
Khaled, M., Rönnbäck, I., Ilag, L. L., Gräslund, A., Strodel, B. & Österlund, N. (2023). A Hairpin Motif in the Amyloid-& beta Peptide Is Important for Formation of Disease-Related Oligomers. Journal of the American Chemical Society, 145(33), 18340-18354
Öppna denna publikation i ny flik eller fönster >>A Hairpin Motif in the Amyloid-& beta Peptide Is Important for Formation of Disease-Related Oligomers
Visa övriga...
2023 (Engelska)Ingår i: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 145, nr 33, s. 18340-18354Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

The amyloid-& beta;(A & beta;) peptide is associated with the developmentof Alzheimer's disease and is known to form highly neurotoxicprefibrillar oligomeric aggregates, which are difficult to study dueto their transient, low-abundance, and heterogeneous nature. To obtainhigh-resolution information about oligomer structure and dynamicsas well as relative populations of assembly states, we here employa combination of native ion mobility mass spectrometry and moleculardynamics simulations. We find that the formation of A & beta; oligomersis dependent on the presence of a specific & beta;-hairpin motif inthe peptide sequence. Oligomers initially grow spherically but startto form extended linear aggregates at oligomeric states larger thanthose of the tetramer. The population of the extended oligomers couldbe notably increased by introducing an intramolecular disulfide bond,which prearranges the peptide in the hairpin conformation, therebypromoting oligomeric structures but preventing conversion into maturefibrils. Conversely, truncating one of the & beta;-strand-formingsegments of A & beta; decreased the hairpin propensity of the peptideand thus decreased the oligomer population, removed the formationof extended oligomers entirely, and decreased the aggregation propensityof the peptide. We thus propose that the observed extended oligomerstate is related to the formation of an antiparallel sheet state,which then nucleates into the amyloid state. These studies provideincreased mechanistic understanding of the earliest steps in A & beta;aggregation and suggest that inhibition of A & beta; folding into thehairpin conformation could be a viable strategy for reducing the amountof toxic oligomers.

Nationell ämneskategori
Kemi
Identifikatorer
urn:nbn:se:su:diva-221322 (URN)10.1021/jacs.3c03980 (DOI)001044984100001 ()37555670 (PubMedID)2-s2.0-85168362360 (Scopus ID)
Tillgänglig från: 2023-09-19 Skapad: 2023-09-19 Senast uppdaterad: 2023-09-19Bibliografiskt granskad
Rajkovic, A., Kanchugal, S., Abdurakhmanov, E., Howard, R., Wärmländer, S., Erwin, J., . . . Coulbourn Flores, S. (2023). Amino acid substitutions in human growth hormone affect coiled-coil content and receptor binding. PLOS ONE, 18(3), Article ID e0282741.
Öppna denna publikation i ny flik eller fönster >>Amino acid substitutions in human growth hormone affect coiled-coil content and receptor binding
Visa övriga...
2023 (Engelska)Ingår i: PLOS ONE, E-ISSN 1932-6203, Vol. 18, nr 3, artikel-id e0282741Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

The interaction between human Growth Hormone (hGH) and hGH Receptor (hGHR) has basic relevance to cancer and growth disorders, and hGH is the scaffold for Pegvisomant, an anti-acromegaly therapeutic. For the latter reason, hGH has been extensively engineered by early workers to improve binding and other properties. We are particularly interested in E174 which belongs to the hGH zinc-binding triad; the substitution E174A is known to significantly increase binding, but to now no explanation has been offered. We generated this and several computationally-selected single-residue substitutions at the hGHR-binding site of hGH. We find that, while many successfully slow down dissociation of the hGH-hGHR complex once bound, they also slow down the association of hGH to hGHR. The E174A substitution induces a change in the Circular Dichroism spectrum that suggests the appearance of coiled-coiling. Here we show that E174A increases affinity of hGH against hGHR because the off-rate is slowed down more than the on-rate. For E174Y (and certain mutations at other sites) the slowdown in on-rate was greater than that of the off-rate, leading to decreased affinity. The results point to a link between structure, zinc binding, and hGHR-binding affinity in hGH.

Nationell ämneskategori
Biofysik
Forskningsämne
biofysik
Identifikatorer
urn:nbn:se:su:diva-202694 (URN)10.1371/journal.pone.0282741 (DOI)000984103600028 ()36952491 (PubMedID)2-s2.0-85150746917 (Scopus ID)
Tillgänglig från: 2022-03-09 Skapad: 2022-03-09 Senast uppdaterad: 2023-06-07Bibliografiskt granskad
Berntsson, E., Vosough, F., Noormagi, A., Padari, K., Asplund, F., Gielnik, M., . . . Wärmländer, S. (2023). Characterization of Uranyl (UO22+) Ion Binding to Amyloid Beta (Aβ) Peptides: Effects on Aβ Structure and Aggregation. ACS Chemical Neuroscience, 14(15), 2618-2633
Öppna denna publikation i ny flik eller fönster >>Characterization of Uranyl (UO22+) Ion Binding to Amyloid Beta (Aβ) Peptides: Effects on Aβ Structure and Aggregation
Visa övriga...
2023 (Engelska)Ingår i: ACS Chemical Neuroscience, E-ISSN 1948-7193, Vol. 14, nr 15, s. 2618-2633Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Uranium (U) is naturally present in ambient air, water, and soil, and depleted uranium (DU) is released into the environment via industrial and military activities. While the radiological damage from U is rather well understood, less is known about the chemical damage mechanisms, which dominate in DU. Heavy metal exposure is associated with numerous health conditions, including Alzheimer’s disease (AD), the most prevalent age-related cause of dementia. The pathological hallmark of AD is the deposition of amyloid plaques, consisting mainly of amyloid-β (Aβ) peptides aggregated into amyloid fibrils in the brain. However, the toxic species in AD are likely oligomeric Aβ aggregates. Exposure to heavy metals such as Cd, Hg, Mn, and Pb is known to increase Aβ production, and these metals bind to Aβ peptides and modulate their aggregation. The possible effects of U in AD pathology have been sparsely studied. Here, we use biophysical techniques to study in vitro interactions between Aβ peptides and uranyl ions, UO22+, of DU. We show for the first time that uranyl ions bind to Aβ peptides with affinities in the micromolar range, induce structural changes in Aβ monomers and oligomers, and inhibit Aβ fibrillization. This suggests a possible link between AD and U exposure, which could be further explored by cell, animal, and epidemiological studies. General toxic mechanisms of uranyl ions could be modulation of protein folding, misfolding, and aggregation. 

Nyckelord
Alzheimer's disease, amyloid aggregation, metal-protein binding, neurodegeneration, heavy metal toxicity
Nationell ämneskategori
Neurovetenskaper Biokemi och molekylärbiologi
Identifikatorer
urn:nbn:se:su:diva-221233 (URN)10.1021/acschemneuro.3c00130 (DOI)001035034000001 ()37487115 (PubMedID)2-s2.0-85166386170 (Scopus ID)
Tillgänglig från: 2023-09-19 Skapad: 2023-09-19 Senast uppdaterad: 2023-09-19Bibliografiskt granskad
Biswas, A., Maloverjan, M., Padari, K., Abroi, A., Rätsep, M., Wärmländer, S. K. T., . . . Pooga, M. (2023). Choosing an Optimal Solvent Is Crucial for Obtaining Cell-Penetrating Peptide Nanoparticles with Desired Properties and High Activity in Nucleic Acid Delivery. Pharmaceutics, 15(2), Article ID 396.
Öppna denna publikation i ny flik eller fönster >>Choosing an Optimal Solvent Is Crucial for Obtaining Cell-Penetrating Peptide Nanoparticles with Desired Properties and High Activity in Nucleic Acid Delivery
Visa övriga...
2023 (Engelska)Ingår i: Pharmaceutics, ISSN 1999-4923, E-ISSN 1999-4923, Vol. 15, nr 2, artikel-id 396Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Cell-penetrating peptides (CPPs) are highly promising transfection agents that can deliver various compounds into living cells, including nucleic acids (NAs). Positively charged CPPs can form non-covalent complexes with negatively charged NAs, enabling simple and time-efficient nanoparticle preparation. However, as CPPs have substantially different chemical and physical properties, their complexation with the cargo and characteristics of the resulting nanoparticles largely depends on the properties of the surrounding environment, i.e., solution. Here, we show that the solvent used for the initial dissolving of a CPP determines the properties of the resulting CPP particles formed in an aqueous solution, including the activity and toxicity of the CPP–NA complexes. Using different biophysical methods such as dynamic light scattering (DLS), atomic force microscopy (AFM), transmission and scanning electron microscopy (TEM and SEM), we show that PepFect14 (PF14), a cationic amphipathic CPP, forms spherical particles of uniform size when dissolved in organic solvents, such as ethanol and DMSO. Water-dissolved PF14, however, tends to form micelles and non-uniform aggregates. When dissolved in organic solvents, PF14 retains its α-helical conformation and biological activity in cell culture conditions without any increase in cytotoxicity. Altogether, our results indicate that by using a solvent that matches the chemical nature of the CPP, the properties of the peptide–cargo particles can be tuned in the desired way. This can be of critical importance for in vivo applications, where CPP particles that are too large, non-uniform, or prone to aggregation may induce severe consequences.

Nyckelord
cell-penetrating peptides, solvent, nanoparticle formation, nucleic acid delivery
Nationell ämneskategori
Biologiska vetenskaper
Identifikatorer
urn:nbn:se:su:diva-215998 (URN)10.3390/pharmaceutics15020396 (DOI)000940877200001 ()36839718 (PubMedID)2-s2.0-85149152654 (Scopus ID)
Tillgänglig från: 2023-03-31 Skapad: 2023-03-31 Senast uppdaterad: 2023-03-31Bibliografiskt granskad
Liu, C., Henning-Knechtel, A., Österlund, N., Wu, J., Wang, G., Gräslund, R. A., . . . Luo, J. (2023). Oligomer Dynamics of LL-37 Truncated Fragments Probed by α-Hemolysin Pore and Molecular Simulations. Small, 19(37), Article ID 2206232.
Öppna denna publikation i ny flik eller fönster >>Oligomer Dynamics of LL-37 Truncated Fragments Probed by α-Hemolysin Pore and Molecular Simulations
Visa övriga...
2023 (Engelska)Ingår i: Small, ISSN 1613-6810, E-ISSN 1613-6829, Vol. 19, nr 37, artikel-id 2206232Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Oligomerization of antimicrobial peptides (AMPs) is critical in their effects on pathogens. LL-37 and its truncated fragments are widely investigated regarding their structures, antimicrobial activities, and application, such as developing new antibiotics. Due to the small size and weak intermolecular interactions of LL-37 fragments, it is still elusive to establish the relationship between oligomeric states and antimicrobial activities. Here, an α-hemolysin nanopore, mass spectrometry (MS), and molecular dynamic (MD) simulations are used to characterize the oligomeric states of two LL-37 fragments. Nanopore studies provide evidence of trapping events related to the oligomer formation and provide further details on their stabilities, which are confirmed by MS and MD simulations. Furthermore, simulation results reveal the molecular basis of oligomer dynamics and states of LL-37 fragments. This work provides unique insights into the relationship between the oligomer dynamics of AMPs and their antimicrobial activities at the single-molecule level. The study demonstrates how integrating methods allows deciphering single molecule level understanding from nanopore sensing approaches. 

Nyckelord
dynamics, LL-37 fragments, nanopores, oligomers
Nationell ämneskategori
Biofysik
Identifikatorer
urn:nbn:se:su:diva-220214 (URN)10.1002/smll.202206232 (DOI)000986112000001 ()37170734 (PubMedID)2-s2.0-85159128314 (Scopus ID)
Tillgänglig från: 2023-08-25 Skapad: 2023-08-25 Senast uppdaterad: 2023-10-12Bibliografiskt granskad
Gielnik, M., Szymańska, A., Dong, X., Jarvet, J., Svedružić, Ž. M., Gräslund, A., . . . Wärmländer, S. . T. (2023). Prion Protein Octarepeat Domain Forms Transient β-Sheet Structures upon Residue-Specific Binding to Cu(II) and Zn(II) Ions. Biochemistry, 62(11), 1689-1705
Öppna denna publikation i ny flik eller fönster >>Prion Protein Octarepeat Domain Forms Transient β-Sheet Structures upon Residue-Specific Binding to Cu(II) and Zn(II) Ions
Visa övriga...
2023 (Engelska)Ingår i: Biochemistry, ISSN 0006-2960, E-ISSN 1520-4995, Vol. 62, nr 11, s. 1689-1705Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Misfolding of the cellular prion protein (PrPC) is associated with the development of fatal neurodegenerative diseases called transmissible spongiform encephalopathies (TSEs). Metal ions appear to play a crucial role in PrPC misfolding. PrPC is a combined Cu(II) and Zn(II) metal-binding protein, where the main metal-binding site is located in the octarepeat (OR) region. Thus, the biological function of PrPC may involve the transport of divalent metal ions across membranes or buffering concentrations of divalent metal ions in the synaptic cleft. Recent studies have shown that an excess of Cu(II) ions can result in PrPC instability, oligomerization, and/or neuroinflammation. Here, we have used biophysical methods to characterize Cu(II) and Zn(II) binding to the isolated OR region of PrPC. Circular dichroism (CD) spectroscopy data suggest that the OR domain binds up to four Cu(II) ions or two Zn(II) ions. Binding of the first metal ion results in a structural transition from the polyproline II helix to the β-turn structure, while the binding of additional metal ions induces the formation of β-sheet structures. Fluorescence spectroscopy data indicate that the OR region can bind both Cu(II) and Zn(II) ions at neutral pH, but under acidic conditions, it binds only Cu(II) ions. Molecular dynamics simulations suggest that binding of either metal ion to the OR region results in the formation of β-hairpin structures. As the formation of β-sheet structures can be a first step toward amyloid formation, we propose that high concentrations of either Cu(II) or Zn(II) ions may have a pro-amyloid effect in TSE diseases.

Nationell ämneskategori
Biologiska vetenskaper
Identifikatorer
urn:nbn:se:su:diva-218066 (URN)10.1021/acs.biochem.3c00129 (DOI)000988877300001 ()37163663 (PubMedID)2-s2.0-85160591106 (Scopus ID)
Tillgänglig från: 2023-07-25 Skapad: 2023-07-25 Senast uppdaterad: 2023-10-12Bibliografiskt granskad
Österlund, N., Frankel, R., Carlsson, A., Thacker, D., Karlsson, M., Matus, V., . . . Linse, S. (2023). The C-terminal domain of the antiamyloid chaperone DNAJB6 binds to amyloid-β peptide fibrils and inhibits secondary nucleation. Journal of Biological Chemistry, 299(11), Article ID 105317.
Öppna denna publikation i ny flik eller fönster >>The C-terminal domain of the antiamyloid chaperone DNAJB6 binds to amyloid-β peptide fibrils and inhibits secondary nucleation
Visa övriga...
2023 (Engelska)Ingår i: Journal of Biological Chemistry, ISSN 0021-9258, E-ISSN 1083-351X, Vol. 299, nr 11, artikel-id 105317Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

The DNAJB6 chaperone inhibits fibril formation of aggregation-prone client peptides through interaction with aggregated and oligomeric forms of the amyloid peptides. Here, we studied the role of its C-terminal domain (CTD) using constructs comprising either the entire CTD or the first two or all four of the CTD β-strands grafted onto a scaffold protein. Each construct was expressed as WT and as a variant with alanines replacing five highly conserved and functionally important serine and threonine residues in the first β-strand. We investigated the stability, oligomerization, antiamyloid activity, and affinity for amyloid-β (Aβ42) species using optical spectroscopy, native mass spectrometry, chemical crosslinking, and surface plasmon resonance technology. While DNAJB6 forms large and polydisperse oligomers, CTD was found to form only monomers, dimers, and tetramers of low affinity. Kinetic analyses showed a shift in inhibition mechanism. Whereas full-length DNAJB6 activity is dependent on the serine and threonine residues and efficiently inhibits primary and secondary nucleation, all CTD constructs inhibit secondary nucleation only, independently of the serine and threonine residues, although their dimerization and thermal stabilities are reduced by alanine substitution. While the full-length DNAJB6 inhibition of primary nucleation is related to its propensity to form coaggregates with Aβ, the CTD constructs instead bind to Aβ42 fibrils, which affects the nucleation events at the fibril surface. The retardation of secondary nucleation by DNAJB6 can thus be ascribed to the first two β-strands of its CTD, whereas the inhibition of primary nucleation is dependent on the entire protein or regions outside the CTD.

Nationell ämneskategori
Biokemi och molekylärbiologi
Identifikatorer
urn:nbn:se:su:diva-224307 (URN)10.1016/j.jbc.2023.105317 (DOI)001101315100001 ()37797698 (PubMedID)2-s2.0-85175246202 (Scopus ID)
Tillgänglig från: 2023-12-06 Skapad: 2023-12-06 Senast uppdaterad: 2023-12-06Bibliografiskt granskad
Gallego-Villarejo, L., Wallin, C., Król, S., Enrich-Bengoa, J., Suades, A., Aguilella-Arzo, M., . . . Perálvarez-Marín, A. (2022). Big dynorphin is a neuroprotector scaffold against amyloid β-peptide aggregation and cell toxicity. Computational and Structural Biotechnology Journal, 20, 5672-5679
Öppna denna publikation i ny flik eller fönster >>Big dynorphin is a neuroprotector scaffold against amyloid β-peptide aggregation and cell toxicity
Visa övriga...
2022 (Engelska)Ingår i: Computational and Structural Biotechnology Journal, E-ISSN 2001-0370, Vol. 20, s. 5672-5679Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Amyloid β-peptide (Aβ) misfolding into β-sheet structures triggers neurotoxicity inducing Alzheimer’s disease (AD). Molecules able to reduce or to impair Aβ aggregation are highly relevant as possible AD treatments since they should protect against Aβ neurotoxicity. We have studied the effects of the interaction of dynorphins, a family of opioid neuropeptides, with Aβ40 the most abundant species of Aβ. Biophysical measurements indicate that Aβ40 interacts with Big Dynorphin (BigDyn), lowering the amount of hydrophobic aggregates, and slowing down the aggregation kinetics. As expected, we found that BigDyn protects against Aβ40 aggregates when studied in human neuroblastoma cells by cell survival assays. The cross-interaction between BigDyn and Aβ40 provides insight into the mechanism of amyloid pathophysiology and may open up new therapy possibilities.

Nyckelord
Alzheimer’s disease, Amyloid b-peptide, Dynorphins, Peptide therapy, Biophysics
Nationell ämneskategori
Cell- och molekylärbiologi
Identifikatorer
urn:nbn:se:su:diva-212495 (URN)10.1016/j.csbj.2022.10.014 (DOI)000930753500004 ()2-s2.0-85140094234 (Scopus ID)
Tillgänglig från: 2022-12-07 Skapad: 2022-12-07 Senast uppdaterad: 2023-03-14Bibliografiskt granskad
Österlund, N., Wärmländer, S. K. T. & Gräslund, A. (2022). Cell-Penetrating Peptides with Unexpected Anti-Amyloid Properties. Pharmaceutics, 14(4), Article ID 823.
Öppna denna publikation i ny flik eller fönster >>Cell-Penetrating Peptides with Unexpected Anti-Amyloid Properties
2022 (Engelska)Ingår i: Pharmaceutics, ISSN 1999-4923, E-ISSN 1999-4923, Vol. 14, nr 4, artikel-id 823Artikel, forskningsöversikt (Refereegranskat) Published
Abstract [en]

Cell-penetrating peptides (CPPs) with sequences derived originally from a prion protein (PrP) have been shown to exhibit both anti-prion and anti-amyloid properties particularly against prion proteins and the amyloid-β (Aβ) peptide active in Alzheimer’s disease. These disease-modifying properties are so far observed in cell cultures and in vitro. The CPP sequences are composed of a hydrophobic signal sequence followed by a highly positively charged hexapeptide segment. The original signal sequence of the prion protein can be changed to the signal sequence of the NCAM1 protein without losing the anti-prion activity. Although the detailed molecular mechanisms of these CPP peptides are not fully understood, they do form amyloid aggregates by themselves, and molecular interactions between the CPPs and PrP/Aβ can be observed in vitro using various spectroscopic techniques. These initial intermolecular interactions appear to re-direct the aggregation pathways for prion/amyloid formation to less cell-toxic molecular structures (i.e., co-aggregates), which likely is why the disease-inducing PrP/Aβ aggregation is counteracted in vivo.

Nyckelord
protein aggregation, secretion signal peptide, peptide engineering, drug design
Nationell ämneskategori
Neurovetenskaper Biologiska vetenskaper
Identifikatorer
urn:nbn:se:su:diva-204559 (URN)10.3390/pharmaceutics14040823 (DOI)000785290300001 ()35456657 (PubMedID)2-s2.0-85128454673 (Scopus ID)
Tillgänglig från: 2022-05-10 Skapad: 2022-05-10 Senast uppdaterad: 2022-05-10Bibliografiskt granskad
Organisationer
Identifikatorer
ORCID-id: ORCID iD iconorcid.org/0000-0003-2187-1537

Sök vidare i DiVA

Visa alla publikationer