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Strong reversible Fe 3+ -mediated bridging between dopa-containing protein films in water
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| Zeitschriftentitel: | Proceedings of the National Academy of Sciences |
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| Personen und Körperschaften: | , , , |
| In: | Proceedings of the National Academy of Sciences, 107, 2010, 29, S. 12850-12853 |
| Format: | E-Article |
| Sprache: | Englisch |
| veröffentlicht: |
Proceedings of the National Academy of Sciences
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| Schlagwörter: |
| Zusammenfassung: | <jats:p> Metal-containing polymer networks are widespread in biology, particularly for load-bearing exoskeletal biomaterials. <jats:italic>Mytilus</jats:italic> byssal cuticle is an especially interesting case containing moderate levels of Fe <jats:sup>3+</jats:sup> and cuticle protein—mussel foot protein-1 (mfp-1), which has a peculiar combination of high hardness and high extensibility. Mfp-1, containing 13 mol % of dopa (3, 4-dihydroxyphenylalanine) side-chains, is highly positively charged polyelectrolyte (pI ∼ 10) and didn’t show any cohesive tendencies in previous surface forces apparatus (SFA) studies. Here, we show that Fe <jats:sup>3+</jats:sup> ions can mediate unusually strong interactions between the positively charged proteins. Using an SFA, Fe <jats:sup>3+</jats:sup> was observed to impart robust bridging ( <jats:italic>W</jats:italic> <jats:sub>ad</jats:sub> ≈ 4.3 mJ/m <jats:sup>2</jats:sup> ) between two noninteracting mfp-1 films in aqueous buffer approaching the ionic strength of seawater. The Fe <jats:sup>3+</jats:sup> bridging between the mfp-1-coated surfaces is fully reversible in water, increasing with contact time and iron concentration up to 10 μM; at 100 μM, Fe <jats:sup>3+</jats:sup> bridging adhesion is abolished. Bridging is apparently due to the formation of multivalent dopa-iron complexes. Similar Fe-mediated bridging ( <jats:italic>W</jats:italic> <jats:sub>ad</jats:sub> ≈ 5.7 mJ/m <jats:sup>2</jats:sup> ) by a smaller recombinant dopa-containing analogue indicates that bridging is largely independent of molecular weight and posttranslational modifications other than dopa. The results suggest that dopa-metal interactions may provide an energetic new paradigm for engineering strong, self-healing interactions between polymers under water. </jats:p> |
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| Umfang: | 12850-12853 |
| ISSN: |
0027-8424
1091-6490 |
| DOI: | 10.1073/pnas.1007416107 |