Fungal infections affect more than one billion people worldwide and cause more than one million deaths per year. Amphotericin B (AmB), a polyene antifungal drug, has been used as the gold standard for many years because of its broad antifungal spectrum, high activity, and low tendency of drug resistance. However, the side effects of AmB, such as nephrotoxicity and hepatotoxicity, have hampered its widespread use, leading to the development of a liposome-type AmB formulation, AmBisome. Herein, we report a simple but highly effective strategy to enhance the antifungal activity of AmBisome with a lipid-modified protein.The chitin-binding domain (LysM) of the antifungal chitinase, Pteris ryukyuensis chitinase A (PrChiA), a small 5.3 kDa protein that binds to fungal cell wall chitin, was engineered to have a glutamine-containing peptide tag at the C-terminus for the microbial transglutaminase (MTG)-catalyzed crosslinking reaction (LysM-Q). LysM-Q was site-specifically modified with a lysine-containing lipid peptide substrate of MTG with a palmitoyl moiety (Pal-K). The resulting palmitoylated LysM (LysM-Pal) exhibited negligible cytotoxicity to mammalian cells and can be easily anchored to yield LysM-presenting AmBisome (LysM-AmBisome). LysM-AmBisome exhibited a dramatic enhancement of antifungal activity toward Trichoderma viride and Cryptococcus neoformans, demonstrating the marked impact of displaying a cell-wall binder protein on the targeting ability of antifungal liposomal formulations. Our simple strategy with enzymatic protein lipidation provides a potent approach to upgrade other types of lipid-based drug formulations.

Enzymatic reaction offers site-specific conjugation of protein units to form protein conjugates or protein polymers with intrinsic functions. Herein, we report horseradish peroxidase (HRP)-and microbial transglutaminase (MTG)-catalyzed orthogonal conjugation reactions to create antifungal protein polymers composed of Pteris ryukyuensis chitinase-A (ChiA) and its two domains, catalytic domain, CatD, and chitin-binding domain, LysM 2 . We engineered the ChiA and CatD by introducing a peptide tag containing tyrosine (Y-tag) at N-termini and a peptide tag containing lysine and tyrosine (KY-tag) at C-termini to construct Y-ChiA-KY and Y-CatD-KY. Also, LysM 2 with Y-tag and KY-tag (Y-LysM 2 -KY) or with a glutamine-containing peptide tag (Q-tag) (LysM 2 -Q) were constructed. The proteins with Y-tag and KY-tag were efficiently polymerized by HRP reaction through the formation of dityrosine bonds at the tyrosine residues in the peptide tags. The Y-CatD-KY polymer was further treated by MTG to orthogonally graft LysM 2 -Q to the KY-tag via isopeptide formation between the side chains of the glutamine and lysine residues in the peptide tags to form LysM 2 -grafted CatD polymer. The LysM 2 -grafted CatD polymer exhibited significantly higher antifungal activity than the homopolymer of Y-ChiA-KY and the random copolymer of Y-CatD-KY and Y-LysM 2 -KY, demonstrating that the structural differences of artificial chitinase polymers have a significant impact on the antifungal activity. This strategy of polymerization and grafting reaction of protein can contribute to the further research and development of functional protein polymers for specific applications in various fields in biotechnology.

Combinations of antifungal drugs can have synergistic antifungal activity, achieving high therapeutic efficacy while minimizing the side effects. Amphotericin B (AMB) has been used as a standard antifungal drug for fungal infections; however, because of its high toxicity, new strategies to minimize the required dose are desirable. Chitinases have recently received attention as alternative safe antifungal agents. Herein, we report the combination of palmitoylated chitinase domains with AMB to enhance the antifungal activity. The chitin-binding domain (LysM) from Pteris ryukyuensis chitinase was site-specifically palmitoylated by conjugation reaction catalyzed by microbial transglutaminase. The palmitoylated LysM (LysM-Pal) exhibited strong antifungal activity against Trichoderma viride, inhibiting the growth completely at a concentration of 2 μM. This antifungal effect of LysM-Pal was mainly due to the effect of anchoring of palmitic acid motif to the plasma membrane of fungi. A combination of AMB with LysM-Pal resulted in synergistic enhancement of the antifungal activity. Intriguingly, LysM-Pal exhibited higher level of antifungal activity enhancement than palmitoylated catalytic domain (CatD) and fusion of LysM and CatD. Addition of 0.5 μM LysM-Pal to AMB reduced the minimal inhibition concentration of AMB to 0.31 μM (2.5 μM without LysM-Pal). The possible mechanism of the synergistic effect of AMB and LysM-Pal is destabilization of the plasma membrane by anchoring of palmitic acid and ergosterol extraction by AMB and destabilization of the chitin layer by LysM binding. The combination of LysM-Pal with AMB can drastically reduce the dose of AMB and may be a useful strategy to treat fungal infections.

Background Coronavirus disease 2019 (COVID-19) is caused by infection with severe acute respiratory syndrome coronavirus 2. COVID-19 has devastating effects on people in all countries and getting worse. We aim to investigate an in-silico docking analysis of phytochemical compounds from medicinal plants that used to combat inhibition of the COVID-19 pathway. There are several phytochemicals in medicinal plants, however, the mechanism of bioactive compounds remains unclear. These results are obtained from in silico research provide further information to support the inhibition of several phytochemicals. Methods Molecular docking used to determine the best potential COVID-19 M pro inhibitor from several bioactive compounds in Moringa oleifera, Allium cepa, Cocos nucifera, Psidium guajava, and Eucalyptus globulus. Molecular docking was conducted and scored by comparison with standard drugs remdesivir. ADME properties of selected ligands were evaluated using the Lipinski Rule. The interaction mechanism of the most recommended compound predicted using the STITCH database. Results There was no recommended compound in Moringa oleifera as a potential inhibitor for COVID-19. Oleanolic acid in Allium cepa, α-tocotrienol in Cocos nucifera, asiatic acid in Psidium guajava and culinoside in Eucalyptus globulus were the most recommended compound in each medicinal plant. Oleanolic acid was reported to exhibit anti-COVID-19 activity with binding energy was − 9.20 kcal/mol. This score was better than remdesivir as standard drug. Oleanolic acid interacted through the hydrogen bond with HIS41, THR25, CYS44, GLU166. Oleanolic acid binding with CASP-3, CASP-9, and XIAP signaling pathway. Conclusions Oleanolic acid in Allium cepa found as a potential inhibitor of COVID-19 M-pro that should be examined in future studies. These results suggest that oleanolic acid may be useful in COVID-19 treatment.

Microbial catalase is an important industrial enzyme that catalyzes the decomposition of hydrogen peroxide into water and oxygen. This enzyme posseses great potential of application in food, textile and pharmaceutical industries. In this paper, Neurospora crassa InaCC F226 was used to produce catalase. The aim of this research was to purify the catalase producing by Neurospora crassa InaCC F226 using gel filtration column chromatography and characterization of temperature, pH, Vmax, Km and molecular weight. In this study, the Neurospora crassa was cultured on Vogel's medium for 5 days. The cells were harvested in the 50 mM buffer sodium phosphate (pH 7) containing 3% hydrogen peroxide. Supernatant containing crude enzymes of Catalase was separated from cells by centrifugation at 15 minutes on 13000 x g and 4 o C. The purification result using gel filtration was specific activity 1464.9 U/mg, 10.7 fold and 21.7% yield. Characterization of the purified enzyme toward pH and temperature optimum was 7.0 (271.6 U/mL) and 40 o C (286.1 U/mL). The K m and V max found to be 8.8 mM and 5.7 s.mM-1. The catalase activity increased by additiom of Fe +2 , Ca +2 and inhibited by EDTA, Cu +2 and Mn +2. The molecular weight of the catalase was 59.4 kDa.