Homologous chaperone-mediated soluble production of Mfp-3 and its application in atopic dermatitis therapy.

Mussel foot proteins (Mfps) are a class of specialized adhesive proteins synthesized by marine mussels. Among these, type 3 mussel foot protein (Mfp-3) has tremendous application potential as a cosmetic and medical raw material, owing to its excellent antioxidant and anti-inflammatory properties. However, the low efficiency of the natural extraction method (only 1 mg of protein can be obtained from 10,000 mussels) has hindered the industrial application. Heterologous expression via genetic recombination offers a reliable alternative. However, a major challenge is that recombinant expression frequently results in misfolded, biologically inactive protein aggregates. In this study, we identified endogenous molecular chaperones in Mytilus galloprovincialis and successfully constructed a strain that co-expresses Mfp-3 and these chaperone proteins, thereby achieving the soluble expression of Mfp-3. Furthermore, through optimization of fermentation conditions, the soluble yield of Mfp-3 in high-density fermentation using a 5-L fermenter reached 713 mg/L. Meanwhile, following in vitro tyrosinase modification, the L-3,4-dihydroxyphenylalanine (DOPA) content of Mfp-3 reached 4.45%, corresponding to a modification rate of 22.26%. On this basis, this study also demonstrated that soluble Mfp-3 possesses excellent cell migration-promoting ability. Moreover, it exhibited superior biological activity in the treatment of atopic dermatitis by reducing levels of pro-inflammatory cytokines and immunoglobulins. This research provides a new strategy for the production of soluble Mfp-3 in Escherichia coli and offers a reference for the large-scale production of soluble Mfps.