Heterologous expression of hagfish thread proteins EsTKα and EsTKγ in Pichia pastoris and in vitro self-assembly into an ordered fibrous network

<i>Eptatretus stoutii</i> thread keratin α and γ (EsTKα and EsTKγ) are essential structural components conferring hagfish slime with exceptional strength and toughness. These proteins exhibit exceptional mechanical properties, rendering them promising candidates for biomimetic material applications. However, the ability of conventional prokaryotic expression systems to produce these proteins is notably limited, as they often fail to achieve proper folding and post-translational modifications. In