| 1. |
- Garcia-Bonete, Maria-Jose, 1989, et al.
(författare)
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Bayesian Analysis of MicroScale Thermophoresis Data to Quantify Affinity of Protein: Protein Interactions with Human Survivin
- 2017
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322 .- 2045-2322. ; 7:1, s. Art. no. 16816-
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Tidskriftsartikel (refereegranskat)abstract
- A biomolecular ensemble exhibits different responses to a temperature gradient depending on its diffusion properties. MicroScale Thermophoresis technique exploits this effect and is becoming a popular technique for analyzing interactions of biomolecules in solution. When comparing affinities of related compounds, the reliability of the determined thermodynamic parameters often comes into question. The thermophoresis binding curves can be assessed by Bayesian inference, which provides a probability distribution for the dissociation constant of the interacting partners. By applying Bayesian machine learning principles, binding curves can be autonomously analyzed without manual intervention and without introducing subjective bias by outlier rejection. We demonstrate the Bayesian inference protocol on the known survivin: borealin interaction and on the putative protein-protein interactions between human survivin and two members of the human Shugoshin-like family (hSgol1 and hSgol2). These interactions were identified in a protein microarray binding assay against survivin and confirmed by MicroScale Thermophoresis.
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| 2. |
- Loureiro, J. A., et al.
(författare)
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Fluorinated beta-sheet breaker peptides
- 2014
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Ingår i: Journal of Materials Chemistry B. - : Royal Society of Chemistry (RSC). - 2050-7518 .- 2050-750X. ; 2:16, s. 2259-2264
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Tidskriftsartikel (refereegranskat)abstract
- The aggregation of amyloid-beta peptide (Ab) has been linked to the formation of neuritic plaques, which are pathological hallmarks of Alzheimer's disease. We synthesized peptides containing fluorinated amino acids and studied their effect on the Ab aggregation. The peptides were based on the sequence LVFFD, in which valine was substituted by either 4,4,4-trifluorovaline or 4-fluoroproline, or the phenylalanine at position 3 was replaced by 3,4,5-trifluorophenylalanine. Our results demonstrate that fluorination of the hydrophobic residue valine or phenylalanine is effective in preventing the Ab aggregation. This study opens up the possibility of using new sequences based on fluorinated amino acids to inhibit the amyloid- fibril formation.
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| 3. |
- Bosaeus, Niklas, 1982, et al.
(författare)
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A stretched conformation of DNA with a biological role?
- 2017
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Ingår i: Quarterly Reviews of Biophysics. - 1469-8994 .- 0033-5835. ; 50, s. UNSP e11-e11
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Tidskriftsartikel (refereegranskat)abstract
- We have discovered a well-defined extended conformation of double-stranded DNA, which we call Sigma-DNA, using laser-tweezers force-spectroscopy experiments. At a transition force corresponding to free energy change Delta G = 1.57 +/- 0.12 kcal (mol base pair)(-1) 60 or 122 base-pair long synthetic GC-rich sequences, when pulled by the 3'-3' strands, undergo a sharp transition to the 1.52 +/- 0.04 times longer Sigma-DNA. Intriguingly, the same degree of extension is also found in DNA complexes with recombinase proteins, such as bacterial RecA and eukaryotic Rad51. Despite vital importance to all biological organisms for survival, genome maintenance and evolution, the recombination reaction is not yet understood at atomic level. We here propose that the structural distortion represented by Sigma-DNA, which is thus physically inherent to the nucleic acid, is related to how recombination proteins mediate recognition of sequence homology and execute strand exchange. Our hypothesis is that a homogeneously stretched DNA undergoes a 'disproportionation' into an inhomogeneous Sigma-form consisting of triplets of locally B-like perpendicularly stacked bases. This structure may ensure improved fidelity of base-pair recognition and promote rejection in case of mismatch during homologous recombination reaction. Because a triplet is the length of a gene codon, we speculate that the structural physics of nucleic acids may have biased the evolution of recombinase proteins to exploit triplet base stacks and also the genetic code.
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| 4. |
- Coelho, S. C., et al.
(författare)
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Encapsulation of a proteasome inhibitor with gold-polysaccharide nanocarriers
- 2014
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Ingår i: Journal of Nanoparticle Research. - : Springer Science and Business Media LLC. - 1388-0764 .- 1572-896X. ; 16:4
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Tidskriftsartikel (refereegranskat)abstract
- Organic-inorganic hybrid nanoparticles are potential effective systems for drug delivery in cancer therapy and diagnosis. Chitosan-gum arabic with entrapped gold nanoparticles were developed as a carrier for an anticancer drug bortezomib. The nanosystem was designed to enhance the proteasome inhibitor activity in pancreatic cell lines, S2-013 and hTERT-HPNE. The hydrodynamic diameter of chitosan-gum arabic-gold nanoparticles loaded with bortezomib is around 330 nm. Laser scanning confocal microscopy images show the uptake of the gold nanoparticle/bortezomib encapsulated in chitosan-gum arabic matrix and the fast internalization of these nano combinations into pancreatic cells. Cytotoxic assays assessed that positively charged nanosystems reduce the cell growth and cell proliferation of S2-013s, but the same effect was not observed in cytotoxic response in hTERT-HPNE cells. The outcomes of this study demonstrate the capacity of chitosan-gum arabic nanocarriers to deliver gold nanoparticles/anticancer drug and to increase the permeation and retention effect in S2-013 cells and minimize drug side effects in HPNE cells. © 2014 Springer Science+Business Media.
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| 5. |
- Coelho, S. C., et al.
(författare)
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Enhancing Proteasome-Inhibitor Effect by Functionalized Gold Nanoparticles
- 2014
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Ingår i: Journal of Biomedical Nanotechnology. - : American Scientific Publishers. - 1550-7033. ; 10:4, s. 717-723
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Tidskriftsartikel (refereegranskat)abstract
- Colloidal gold nanoparticles intensify the anticancer response of the drug bortezomib, a proteasome inhibitor. Polyethylene glycol-coated gold nanoparticles and the drug show a synergistic effect in reducing the cell viability of prostate cancer cell line Du145. It was observed a significant cell viability reduction with bortezomib concentrations as low as 4 nM. The proteasome inhibitor alone had to be present at concentrations in the ranger of 120 nM to induce identical cytotoxicity response. These findings demonstrate that gold nanoparticles enhancing the permeation and retention (EPR) effect in Du145 cells and open the possibility to decrease multi-drug resistance (MDR). The in vitro results of functionalized gold nanoparticles, internalized by cancer cells, pave the way for a more efficient proteasome inhibitor delivery and release in adenocarcinoma cells.
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| 6. |
- Coelho, S. C., et al.
(författare)
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Gold nanoparticle delivery-enhanced proteasome inhibitor effect in adenocarcinoma cells
- 2013
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Ingår i: Expert Opinion on Drug Delivery. - : Informa Healthcare. - 1742-5247 .- 1744-7593. ; 10:10, s. 1345-1352
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Tidskriftsartikel (refereegranskat)abstract
- Background: Proteasome inhibition is a current therapeutic strategy used in the treatment of multiple myeloma. Drugs controlling proteasome activity are ideally suited for unidirectional manipulation of cellular pathways such as apoptosis. The first proteasome inhibitor approved in clinics was bortezomib. This drug is currently used in combination with other anticancer agents. Objectives: In this study, the enhancement of bortezomib activity was evaluated using gold nanoparticles coated with poly(ethylene glycol). The uptake mechanism of the gold nanoparticles in pancreatic cell lines, S2-013 and hTERT-HPNE, was assessed by laser scanning confocal microscopy (LSCM). Results: Pancreatic cancer cells internalized the nanoparticles together with the drug in few minutes through the formation of endocytic vesicles. This rapid uptake leads to an increase in the concentration and diffusion of bortezomib in the cytoplasm yielding an increased toxicity on the cells when compared to the drug alone. Conclusion: Gold nanoparticles can be used as effective delivery systems to increasing the permeation and retention of drugs in cancer cells.
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| 7. |
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| 8. |
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| 9. |
- Dedic, Jan, et al.
(författare)
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Membrane-Protein-Hydration Interaction of α-Synuclein with Anionic Vesicles Probed via Angle-Resolved Second-Harmonic Scattering
- 2019
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Ingår i: Journal of Physical Chemistry B. - : American Chemical Society (ACS). - 1520-5207 .- 1520-6106. ; 123:5, s. 1044-1049
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Tidskriftsartikel (refereegranskat)abstract
- Amyloid formation of the protein α-synuclein promotes neurodegeneration in Parkinson's disease. The normal function of α-synuclein includes synaptic vesicle transport and fusion, and the protein binds strongly to negatively charged vesicles in vitro. Here, we demonstrate that nonresonant angle-resolved second-harmonic scattering detects α-synuclein binding to liposomes through changes in water orientational correlations and can thus be used as a high-accuracy and high-throughput label-free probe of protein-liposome interactions. The obtained results support a binding model in which the N-terminus of α-synuclein adopts an α-helical conformation that lies flat on the vesicle surface while the negatively charged C-terminus remains in solution.
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| 10. |
- Hannestad, Jonas, 1981, et al.
(författare)
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Single-vesicle imaging reveals lipid-selective and stepwise membrane disruption by monomeric α-synuclein
- 2020
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 117:25, s. 14178-14186
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Tidskriftsartikel (refereegranskat)abstract
- The interaction of the neuronal protein α-synuclein with lipid membranes appears crucial in the context of Parkinson's disease, but the underlying mechanistic details, including the roles of different lipids in pathogenic protein aggregation and membrane disruption, remain elusive. Here, we used single-vesicle resolution fluorescence and label-free scattering microscopy to investigate the interaction kinetics of monomeric α-synuclein with surface-tethered vesicles composed of different negatively charged lipids. Supported by a theoretical model to account for structural changes in scattering properties of surface-tethered lipid vesicles, the data demonstrate stepwise vesicle disruption and asymmetric membrane deformation upon α-synuclein binding to phosphatidylglycerol vesicles at protein concentrations down to 10 nM (∼100 proteins per vesicle). In contrast, phosphatidylserine vesicles were only marginally affected. These insights into structural consequences of α-synuclein interaction with lipid vesicles highlight the contrasting roles of different anionic lipids, which may be of mechanistic relevance for both normal protein function (e.g., synaptic vesicle binding) and dysfunction (e.g., mitochondrial membrane interaction).
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