Effect of Chemical Chaperones on Glucose-Induced Lysozyme Modifications

Abstract

Nonenzymatic glycation of biomacromolecules occurs due to the diabetes mellitus and ageing. A number of small molecules, known as chemical chaperones, stabilize protein conformation against thermal and chemically induced denaturation. These compounds are including: polyamines (e.g. spermine and spermidine), amino acids (e.g. lysine) and polyols (e.g. glycerol). In this study the effect of spermidine (Spd), spermine (Spm), and glycerol on glycation, structure and function of lysozyme (LZ), as an extra-cellular protein, by different techniques is investigated. LZ is incubated with or without glucose (50 or 100 mM) in the absence or presence of Spd/Spm/glycerol at 37 °C up to 16 weeks. All the observed changes of glycated-LZ in comparison with the native protein, including: increased fluorescence emission, alteration in the secondary and tertiary structure, and reduced electrophoretic mobility- indicate its structural changes that are accompanied with its reduced activity. Glucose in the presence or absence of Spd induces the protein dimerization, but glucose plus Spm induces its trimmerization. In contrast, glycerol inhibits the LZ glycation and prevents the large changes on its structure and function. Glucose binds lysine residues, decreases the protein positive charges and induces some alterations in its structure and activity. Polyamines also directly bind to LZ, increase its positive charges and hence induce more glycation; more conformational changes, oligomerization and its inactivation in the presence of glucose, but glycerol affect the protein environment and preserve protein from these harmful effects.

The effect of cold atmospheric plasma on diabetes-induced enzyme glycation, oxidative stress, and inflammation; in vitro and in vivo

“…An aliquot of the prepared GPx solution was combined with glucose solution and named glycated GPx. Then, pure GPx and glycated GPx samples were filtered under the sterilized condition and incubated for 16 weeks at 37 °C 46,47 . At the end of 16th week, Glycated GPx was treated by cold plasma, and an aliquot of each of the three solutions (pure GPx, glycated GPx, and treated glycated GPx) was taken, and kept at −80 °C until could be analyzed by three methods: Circular Dichroism (CD), fluorometry, and activity assay 48 .…”

Influence of different concentrations of two chemical chaperones on human islet amyloid polypeptide folding under experimental conditions

“…Data is shown as mean ± SD; n = 6. influence the folding of amylin in vitro (Mirhashemi andAarabi, 2011a, 2012c;Mirhashemi and Shahabaddin, 2011b). A number of small molecules, known as chemical chaperones such as glycerol and spermine have important role in protein conformation against thermal and chemically induced denaturation (Bathaie et al, 2011). Since there is no data concerning effect of glycerol and spermine as chemical chaperones on amylin folding, thus, the present study was designed.…”

L-lysine protects C2C12 myotubes and 3T3-L1 adipocytes against high glucose damages and stresses

“…As mentioned in the introduction, our previous in vitro and in vivo studies indicated that chronic hyperglycemia affects the structure and function of many proteins, including extracellular proteins (such as fibrinogen [24] and lysozyme [23, 25]), intracellular proteins, including cytosolic proteins (hemoglobin) [19] and even, nuclear proteins (histone H1 [46]), as well as molecular chaperones (α-crystallin) [26]. Other studies indicated that membrane proteins also affected by this harmful condition [47, 48].…”

“…In this case, they prevent protein misfolding and/or unfolding. Lys with a long side chain and two free amino groups shows no toxicity in the rat up to 5% w/w in oral intake [22], inhibits the nonenzymatic glycation of proteins, protects the protein structure and conserves the folding of many proteins in both in vitro experiments [19, 23–25] and in the rat model of diabetes [19, 26]. Lys treatment has also shown some improvement against complications in type 2 diabetic patients [24, 25].…”