Study on the enhancement of adhesion properties of recombinant mussel adhesive proteins by copper ion-assisted tyrosinase co-expression strategy.

Mussel adhesion proteins are widely used in biomedical fields due to their wet adhesion properties. However, tyrosine residues have been modified with limited efficiency in the development of recombinant mussel adhesins. In this study, the recombinant fp-151 and tyrosinase of Verrucomicrobium spinosum (tyrVS) were successfully co-expressed in E. coli for the first time. Moreover, we systematically explored whether the increased activity of tyrVS caused by the introduction of copper ions during the induction process could effectively improve the adhesion property of fp-151, and the addition of copper ions was applied to the expression of fp-151. The results indicate that the introduction of copper ions effectively increased the activity of tyrVS to 39.33 U/mg protein without affecting the expression of fp-151. Through NBT/glycine staining, surface coating investigations, and batch adhesion strength analyses, this strategy significantly improved the DOPA level in fp-151, resulting in enhanced adhesion performance, with batch adhesion strength increasing by 1.5 times. Furthermore, the sample demonstrated the ability to adhere to HaCaT cells without causing additional cytotoxicity. Therefore, this strategy may provide a crucial foundation for the development of recombinant mussel adhesive proteins.