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- Hedlund, Julia, 1975, et al.
(författare)
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Change of Colloidal and Surface Properties of Mytilus edulis Foot Protein 1 in the Presence of an Oxidation (NaIO4) or a Complex-Binding (Cu2+) Agent
- 2009
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Ingår i: Biomacromolecules. - : American Chemical Society (ACS). - 1525-7797 .- 1526-4602. ; 10:4, s. 845-849
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Tidskriftsartikel (refereegranskat)abstract
- Quartz crystal microbalance with dissipation monitoring (QCM-D) was used to study the viscoelastic properties of the blue mussel, Mytilus edulis, foot protein 1 (Mefp-1) adsorbed on modified hydrophobic gold surfaces. The change in viscoelasticity was studied after addition of Cu2+ and Mn2+, which theoretically could induce metal complex formation with 3,4-dihydroxyphenylalanine (DOPA) moieties. We also used NaIO4, a nonmetal oxidative agent known to induce di-DOPA formation. Reduction in viscoelasticity of adsorbed Mefp-1 followed the order of NaIO4 > Cu2+ > buffer control > Mn2+. We also studied the formation of molecular aggregates of Mefp-1 in solution with the use of dynamic light scattering (DLS). We found that addition of Cu2+, but not Mn2+, induced the formation of larger DLS-detectable aggregates. Minor aggregate formation was found with NaIO4. With the analytical resolution of small angle X-ray scattering (SAXS), we could detect differences in the molecular structure between NaIO4- and Cu2+-treated Mefp-1 aggregates. We concluded from this study that Cu2+ could participate in intermolecular cross-linking of the Mefp-1 molecule via metal complex formation. Metal incorporation in the protein most likely increases the abrasion resistance of the Mefp-1 layer. NaIO4, on the other hand, resulted in mainly intramolecular formation of di-DOPA, but failed to induce larger intermolecular aggregation phenomena. The described methodological combination of surface sensitive methods, like QCM-D, and bulk sensitive methods, like DLS and SAXS, generates high resolution results and is an attractive platform to investigate intra- and intermolecular aspects of assembly and cross-linking of the Mefp proteins.
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| 2. |
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| 3. |
- Berglin, Mattias, 1970, et al.
(författare)
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Use of surface-sensitive methods for the study of adsorption and cross-linking of marine bioadhesives
- 2005
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Ingår i: Journal of Adhesion. - : Informa UK Limited. - 0021-8464 .- 1563-518X .- 1545-5823. ; 81:7-8, s. 805-822
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Tidskriftsartikel (refereegranskat)abstract
- The establishment of the bond of sessile marine organisms such as barnacles, mussels, and algae in the marine environment starts with the secretion and the adsorption of the adhesive biopolymers to the substrate. Subsequently, this is followed by the formation of cohesive interactions with the next layer of adhesive biopolymers that are deposited/adsorbed on top of the first layer. These two fundamental processes for the adhesive plaque buildup have been subjected to several investigations in recent years using model molecules, especially Mefp-1 extracted from the blue mussel Mytilus edulis. With the introduction of optical surface-sensitive methods such as ellipsometry, surface plasmon resonance (SPR), and infrared spectroscopy (IR), it has been possible to elucidate both the kinetics of adsorption and structure of the Mefp-1 film. In contrast to adsorption, the cohesive interactions or the cross-linking are not easily followed with these optical methods and new approaches and techniques are required. One such technique that has been useful is the quartz-crystal microbalance with dissipation monitoring (QCM-D), which has been used for cross-linking studies of a variety of biopolymers including bioadhesives from mussel and algae. Copyright © Taylor & Francis Inc.
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| 4. |
- Fant, Camilla, et al.
(författare)
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Investigation of Adsorption and Cross-Linking of a Mussel Adhesive Protein Using Attenuated Total Internal Reflection Fourier Transform Infrared Spectroscopy (ATR-FTIR)
- 2010
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Ingår i: Journal of Adhesion. - : Informa UK Limited. - 0021-8464 .- 1545-5823 .- 1563-518X. ; 86:1, s. 25-38
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Tidskriftsartikel (refereegranskat)abstract
- Mytilus edulis foot protein 1 (Mefp-1) contains the redox-functional amino acid 3,4-dihydroxyphenylalanine (DOPA), which is a typical feature of most mefp proteins. We have previously shown, using combined optic (ellipsometry) and acoustic (QCM-D) measurements, that the oxidizing agent sodium periodate (NaIO4) and the transition metal ion Cu2+ promote cross-linking of Mefp-1. However, different chemical reaction mechanisms can not be distinguished using these methods. In the present study, we have complemented our previous investigations using Attenuated Total Internal Reflection Fourier Transform Infrared spectroscopy (ATR-FTIR), allowing a spectroscopic analysis of NaIO4 and Cu2+-induced cross-linking of Mefp-1 adsorbed on a ZnSe surface. In aqueous solution, adsorbed Mefp-1 displays absorption bands at 1570, 1472, 1260, and 973 cm(-1). Upon addition of NaIO4 and Cu2+, the absorptions at 1570, 1472, and 973 cm(-1) increase by approximately a factor of two. In contrast, the band at 1260 cm(-1) disappears upon cross-linking using NaIO4, but remains unchanged upon addition of Cu2+. This demonstrates that the band at 1260cm(-1) is attributed to the C O stretching vibration of the side chain hydroxyl groups in DOPA and that Cu2+ forms complexes with DOPA rather than transform it into an o-quinone. Moreover, upon addition of NaIO4 after cross-linking using Cu2+, the band at 1260cm(-1) disappears, indicating that the complex formation between DOPA and Cu2+ is reversed when DOPA is transformed into the o-quinone. These results demonstrate that NaIO4, which initiates a similar reaction to the naturally occurring enzyme catechol oxidase, contributes to the formation of di-DOPA cross-links. In contrast, the dominating contribution to the cross-linking from Cu2+, which is accumulated at high concentrations in the byssus thread of the blue mussel, is via complex formation between the metal and DOPA residues.
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