Hydrophobic Enhancement of Dopa-Mediated Adhesion in a Mussel Foot Protein

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• 作者：Wei Wei ; Jing Yu ; Christopher Broomell ; Jacob N. Israelachvili ; J. Herbert Waite
• 刊名：The Journal of the American Chemical Society
• 出版年：2013
• 出版时间：January 9, 2013
• 年：2013
• 卷：135
• 期：1
• 页码：377-383
• 全文大小：413K
• 年卷期：v.135,no.1(January 9, 2013)
• ISSN：1520-5126

文摘

Dopa (3,4-dihydroxyphenylalanine) is recognized as a key chemical signature of mussel adhesion and has been adopted into diverse synthetic polymer systems. Dopa鈥檚 notorious susceptibility to oxidation, however, poses significant challenges to the practical translation of mussel adhesion. Using a surface forces apparatus to investigate the adhesion of mussel foot protein 3 (Mfp3) 鈥渟low鈥? a hydrophobic protein variant of the Mfp3 family in the plaque, we have discovered a subtle molecular strategy correlated with hydrophobicity that appears to compensate for Dopa instability. At pH 3, where Dopa is stable, Mfp3 slow, like Mfp3 鈥渇ast鈥?adhesion to mica, is directly proportional to the mol % of Dopa present in the protein. At pH of 5.5 and 7.5, however, loss of adhesion in Mfp3 slow was less than half that occurring in Mfp3 fast, purportedly because Dopa in Mfp3 slow is less prone to oxidation. Indeed, cyclic voltammetry showed that the oxidation potential of Dopa in Mfp3 slow is significantly higher than in Mfp3 fast at pH of 7.5. A much greater difference between the two variants was revealed in the interaction energy of two symmetric Mfp3 slow films (E_ad = 鈭? mJ/m²). This energy corresponds to the energy of protein cohesion which is notable for its reversibility and pH independence. Exploitation of aromatic hydrophobic sequences to protect Dopa against oxidation as well as to mediate hydrophobic and H-bonding interactions between proteins provides new insights for developing effective artificial underwater adhesives.