Thiol-Rich fp‑6 Controls the Tautomer Equilibrium of Oxidized Dopa in Interfacial Mussel Foot Proteins

• Published in: Langmuir Vol. 38; no. 11; pp. 3446 - 3452
• Main Authors: Shin, Mincheol, Yoon, Taehee, Yang, Byeongseon, Cha, Hyung Joon
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 22-03-2022
• Subjects: Adhesives; Animals; Bivalvia; Dihydroxyphenylalanine - chemistry; Isomerism; Oxidation-Reduction; Recombinant Proteins; Sulfhydryl Compounds
• ISSN: 0743-7463; 1520-5827
• DOI: 10.1021/acs.langmuir.1c03239

3,4-Dihydroxyphenylalanine (Dopa) is a versatile molecule that enables marine mussels to achieve successful underwater adhesion. However, due to its complicated redox chemistry and vulnerability to oxidation, controlling surface adhesion and cohesion has been a challenging issue to overcome. Foot protein type 6 (fp-6), a thiol-rich interfacial mussel adhesive protein, has been reported as a proteinaceous antioxidant for mussels that helps Dopa maintain surface adhesion ability. In this study, we focused on the role of fp-6 in oxidized Dopa. The effect on the tautomer equilibrium of oxidized Dopa was investigated using recombinant fp-6 (rfp-6) and Dopa-incorporated foot protein type 3 fast variant (drfp-3F), which were produced in bacterial cells. The redox chemistry of Dopa in drfp-3F and the role of rfp-6 were observed using a UV–vis spectrophotometer and a surface forces apparatus (SFA). We discovered that rfp-6 shifts the tautomer equilibrium to ΔDopa as a preferred tautomer for oxidized Dopa in drfp-3F and makes drfp-3F better on underwater surface adhesion.