Abstract
Lectins are widely distributed in the natural world and are usually involved in antitumor activities. Auricularia auricula (A. auricula) is a medicinal and edible homologous fungus. A. auricula contains many active ingredients, such as polysaccharides, melanin, flavonoids, adenosine, sterols, alkaloids, and terpenes. In this study, we expected to isolate and purify lectin from A. auricula, determine the glycoside bond type and sugar-specific protein of A. auricula lectin (AAL), and finally, determine its antitumor activities. We used ammonium sulfate fractionation, ion exchange chromatography, and affinity chromatography to separate and purify lectin from A. auricula. The result was a 25 kDa AAL with a relative molecular mass of 18913.22. Protein identification results suggested that this lectin contained four peptide chains by comparing with the UniProt database. The FT-IR and β-elimination reaction demonstrated that the connection between the oligosaccharide and polypeptide of AAL was an N-glucoside bond. Analyses of its physical and chemical properties showed that AAL was a temperature-sensitive and acidic/alkaline-dependent glycoprotein. Additionally, the anticancer experiment manifested that AAL inhibited the proliferation of A549, and the IC50 value was 28.19 ± 1.92 μg/mL. RNA sequencing dataset analyses detected that AAL may regulate the expression of JUN, TLR4, and MYD88 to suppress tumor proliferation. Through the pulmonary flora analysis, the bacterial structure of each phylum in the lectin treatment group was more reasonable, and the colonization ability of the normal microflora was improved, indicating that lectin treatment could significantly improve the bacterial diversity characteristics.
Highlights
Lectins are proteins or glycoproteins that have at least one carbohydrate or derivative binding site and are different from immunoglobulin in nature and do not have the function of catalytic enzymes
There was a single elution peak of lectin isolated by affinity chromatography, which indicated that we got a single purity lectin through the extraction and purification steps (Figure 2(b))
Fourier transform infrared spectroscopy (FT-IR) and β-elimination reaction of the A. auricula lectin structure were analyzed, and the results show that the linkage between the lectin glycosyl chain and the polypeptide is an N-glucoside bond
Summary
Lectins are proteins or glycoproteins that have at least one carbohydrate or derivative binding site and are different from immunoglobulin in nature and do not have the function of catalytic enzymes. They can recognize and bind to sugars or sugar chains without changing the covalent structure [1]. Lectins are widely distributed in nature, ranging from microorganisms to animals and plants. Fungi lectins are the most studied in the past decades and show different structures, functions, and carbohydrate-binding specificities [3].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
