| 1. |
- Barrantes, Alejandro, et al.
(författare)
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Alzheimer’s Disease Amyloid Peptides Interact with DNA, As Proved by Surface Plasmon Resonance
- 2012
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Ingår i: Current Alzheimer Research. - : Bentham eBooks. - 1567-2050 .- 1875-5828. ; 9:8, s. 924-934
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Tidskriftsartikel (refereegranskat)abstract
- According to the amyloid hypothesis, abnormal processing of the β-amyloid precursor protein in Alzheimer's disease patients increases the production of β-amyloid toxic peptides, which, after forming highly aggregated fibrillar structures, lead to extracellular plaques formation, neuronal loss and dementia. However, a great deal of evidence has point to intracellular small oligomers of amyloid peptides, probably transient intermediates in the process of fibrillar structures formation, as the most toxic species. In order to study the amyloid-DNA interaction, we have selected here three different forms of the amyloid peptide: Aβ1-40, Aβ25-35 and a scrambled form of Aβ25-35. Surface Plasmon Resonance was used together with UV-visible spectroscopy, Electrophoresis and Electronic Microscopy to carry out this study. Our results prove that, similarly to the full length Aβ1-42, all conformations of toxic amyloid peptides, Aβ1-40 and Aβ25-35, may bind DNA. In contrast, the scrambled form of Aβ25-35, a non-aggregating and nontoxic form of this peptide, could not bind DNA. We conclude that although the amyloid-DNA interaction is closely related to the amyloid aggregation proneness, this cannot be the only factor which determines the interaction, since small oligomers of amyloid peptides may also bind DNA if their predominant negatively charged amino acid residues are previously neutralized.
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| 2. |
- Barrantes, Alejandro, et al.
(författare)
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Influence of pH on the build-up of poly-L-lysine/heparin multilayers
- 2012
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Ingår i: Journal of Colloid and Interface Science. - : Elsevier. - 0021-9797 .- 1095-7103. ; 388:1, s. 191-200
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Tidskriftsartikel (refereegranskat)abstract
- The effect of pH on the build-up-of polyelectrolyte multilayers, PEMs, composed by poly-L-lysine and heparin onto two different substrates, silica and gold, has been studied by means of ellispmetry and quartz crystal microbalance with dissipation, QCM-D. Ellipsometry results indicate that the dry mass grows exponentially with the number of layers, and that this amount is larger as the pH values are raised. From QCM-D data the viscoelastic properties of the multilayered structure have been obtained. These data reflect that PEMs become more viscoelastic as the pH values are increased for silica substrates, while for gold the highest viscoelastic behavior is obtained at neutral pH and the elastic behavior becomes dominant as the pH is further increased or decreased. By combining these two surface techniques it has been also possible to determine the solvent content in the multilayers and reach a deeper understanding of the internal structure.
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| 3. |
- Sotres, Javier, et al.
(författare)
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AFM-based friction force spectroscopy : a novel methodology for the study of the strength and lateral diffusion of proteinaceous films
- 2012
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Ingår i: Proteins at Interfaces III State of the Art. - Washington, DC : American Chemical Society (ACS). - 9780841227972 - 9780841227965 ; , s. 129-151
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- We present a novel methodology for the study of proteinaceous films based on the friction force spectroscopy operation mode of the atomic force microscope. It provides information both on the strength at the nanoscale level and on the lateral diffusion properties of these systems. The usefulness of the data generated by this methodology are shown through its application to the study of different types of monolayers of model proteins, as well as to the study of the more complex and heterogeneous salivary films.
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