METHODS AND RESULTS: The tropomyosin gene was cloned and expressed in the Escherichia coli system, followed by SDS-PAGE and immunoblotting test to identify the allergenic potential of the recombinant protein. The 855-base pair of tropomyosin gene produced was found to be 99.18% homologous to Scylla serrata. Its 284 amino acids matched the tropomyosin of crustaceans, arachnids, insects, and Klebsiella pneumoniae, ranging from 79.03 to 95.77%. The tropomyosin contained 89.44% alpha-helix folding with a tertiary structure of two-chain alpha-helical coiled-coil structures comprising a homodimer heptad chain. IPTG-induced histidine tagged-recombinant tropomyosin was purified at the size of 42 kDa and confirmed as tropomyosin using anti-tropomyosin monoclonal antibodies. The IgE binding of recombinant tropomyosin protein was reactive in 90.9% (20/22) of the sera from crab-allergic patients.
CONCLUSIONS: This study has successfully produced an allergenic recombinant tropomyosin from S. olivacea. This recombinant tropomyosin may be used as a specific allergen for the diagnosis of allergy.
OBJECTIVE: Complexation of rHuKGF with mucoadhesive low molecular weight chitosan to protect rHuKGF from proteolysis and investigate the effect of chitosan-rHuKGF complex on the proliferation rate of FHs 74 Int cells.
METHODS: The interaction between chitosan and rHuKGF was studied by molecular docking. Malvern ZetaSizer Nano Zs and Fourier-Transform Infrared spectroscopy (FTIR) tests were carried out to characterize the chitosan-rHuKGF complex. In addition, SDS-PAGE was performed to investigate the interaction between chitosan-rHuKGF complex and pepsin. The effect of chitosan-rHuKGF complex on the proliferation rate of FHs 74 Int cells was studied by MTT assay.
RESULTS: Chitosan-rHuKGF complex was formed through the hydrogen bonding proven by the docking studies. A stable chitosan-rHuKGF complex was formed at pH 4.5 and was protected from proteolysis and assessed by SDS PAGE. According to the MTT assay results, chitosan-rHuKGF complex increased the cell proliferation rate of FHs 74 Int cells.
CONCLUSION: The developed complex improved the stability and the biological function of rHuKGF.