Correlation of the Structure and Bioactivity of Recombinant Fungal Immunomodulatory Protein, Ling-Zhi-8 (LZ-8) Following Exposure to Denaturing Conditions

Abstract

Ling-Zhi-8 (LZ-8), a low-molecular weight protein from Ganoderma lucidum, exerts immunomodulatory effects in vitro and in vivo. The aim of this study was to investigate the effects of exposure of LZ-8 to denaturing conditions on its ability to suppress inflammatory responses in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. Ultraviolet, fluorescence and circular dichroism spectroscopy analyses showed that LZ-8 was not denatured by exposure to pH extremes, but was irreversibly denatured by temperatures above 55C. LZ-8 lowered the production of nitric oxide and interleukin-6, but had no effect on the level of tumor necrosis factor-α. Heat and acid/alkali-treated preparations of LZ-8 had comparable capacity to suppress proinflammatory mediator production. Since native and denatured LZ-8 were both anti-inflammatory, it appears that this particular biological property of LZ-8 is not dependent on the native structure of the protein, but, possibly on a relatively small peptide domain of LZ-8. PRACTICAL APPLICATIONSRecent evidence suggests that LZ-8, a small protein originally isolated from G. lucidum, has immunomodulatory and anti-carcinogenic properties. In this study, LZ-8 exerted an anti-inflammatory effect on LPS-stimulated macrophages, but this effect was not dependent on the native protein structure, suggesting that the entire protein might not be responsible for the bioactive properties of LZ-8. Since the biological functions of LZ-8 were resistant to heating and exposure to acid or alkali, LZ-8 could have applications in food-processing industries and the production of pharmaceuticals. Furthermore, peptides derived from LZ-8 may be potential targets for development of novel anti-carcinogenic and immunomodulatory agents.

Identification of a Novel Anti-cancer Protein, FIP-bbo, from Botryobasidium botryosum and Protein Structure Analysis using Molecular Dynamic Simulation

“…Numerous studies have shown that FIP possess broad spectrum immunomodulatory and anticancer activities, suggesting that they may be promising candidates in clinical disease therapies or for treatment as adjuvant agents 4,17 . FIP can be orally consumed and have high stability when exposed to denaturing conditions 18,19 . These characteristics make FIP a potential candidate to be used as an additive in the health food industry.…”

Current Understanding of the Structure and Function of Fungal Immunomodulatory Proteins

“…That means they are rather digestion-resistant, or that some vital domain, responsible for their bioactivity, reaches the intestinal tract intact. In some articles, the thermal stability and digestion resistance of FIPs have been described ( 111 , 118 – 120 ). Additional research will deliver details about essential domains as well as their utilization.…”