Adhesion is essential for many marine sessile organisms. Unraveling the compositions and assembly of marine bioadheisves is the fundamental to understand their physiological roles. Despite the remarkable diversity of animal bioadhesion, our understanding of this biological process remains limited to only a few animal lineages, leaving the majority of lineages remain enigmatic. Our previous study demonstrated that scallop byssus had distinct protein composition and unusual assembly mechanism apart from mussels. Here a novel protein (Sbp9) was discovered from the key part of the byssus (byssal root), which contains two Calcium Binding Domain (CBD) and 49 tandem Epidermal Growth Factor-Like (EGFL) domain repeats. Modular architecture of Sbp9 represents a novel chimeric gene family resulting from a gene fusion event through the acquisition of CBD2 domain by tenascin like (TNL) gene from Na+/Ca2+
exchanger 1 (NCX1) gene. Finally, free thiols are present in Sbp9 and the results of a rescue assay indicated that Sbp9 likely plays the cohesive role for byssal root integrity. This study not only aids our understanding of byssus assembly but will also inspire biomimetic material design.
Biologically derived and biologically inspired fibers with outstanding mechanical properties have found attractive technical applications across diverse fields. Despite recent advances, few fibers can simultaneously possess high-extensibility and self-recovery properties especially under wet conditions. Here, we report protein-based fibers made from recombinant scallop byssal proteins with outstanding extensibility and self-recovery properties. We initially investigated the mechanical properties of the native byssal thread taken from scallop Chlamys farreri and reveal its high extensibility (327 ± 32%) that outperforms most natural biological fibers. Combining transcriptome and proteomics, we select the most abundant scallop byssal protein type 5-2 (Sbp5-2) in the thread region, and produce a recombinant protein consisting of 7 tandem repeat motifs (rTRM7) of the Sbp5-2 protein. Applying an organic solvent-enabled drawing process, we produce bio-inspired extensible rTRM7 fiber with high-extensibility (234 ± 35%) and self-recovery capability in wet condition, recapitulating the hierarchical structure and mechanical properties of the native scallop byssal thread. We further show that the mechanical properties of rTRM7 fiber are highly regulated by hydrogen bonding and intermolecular crosslinking formed through disulfide bond and metal-carboxyl coordination. With its outstanding mechanical properties, rTRM7 fiber can also be seamlessly integrated with graphene to create motion sensors and electrophysiological signal transmission electrode.
Cardiovascular diseases (CVDs) are the leading causes of premature death and disability in people around the world. Therefore, the prevention and treatment of CVDs has become an important subject. In this study, we verified the thrombolytic activities of a nattokinase‐like protease named NK‐01 in vivo. Label‐free liquid chromatography–tandem mass spectrometry (LC‐MS/MS) technique was used in our study. NK‐01 could inhibit the activity of coagulation factors though the up‐regulation of proteinase C inhibitors and protein S. NK‐01 also could inhibit the angiotensinogen conversion to AngII and promote the degradation of kininogen to reduce the blood pressure. In addition, NK‐01 could increase the content of paraoxonase 1, which could prevent atherosclerosis. In our study, we found that NK‐01 cloud effect some key proteins which participant in CVDs associated metabolic processes such as coagulation system, blood pressure, and atherosclerosis. Taken together, the underlying molecular mechanisms for the biological beneficial of NK‐01 were investigated. Our proteomic study will provide further theoretical basis for application of NK in prevention or adjuvant treatment in biomedicine areas.
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