Open AccessMethylglyoxal produces more changes in biochemical and biophysical properties of human IgG under high glucose compared to normal glucose level
Author(s) -
Mohd Adnan Khan,
Zarina Arif,
Mohd Asad Khan,
Mohammed Moinuddin,
Khursheed Alam
Publication year - 2018
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0191014
Subject(s) - methylglyoxal , glycation , hyperchromicity , thioflavin , chemistry , biochemistry , congo red , oxidative stress , lysine , immunoglobulin g , amide , advanced glycation end product , enzyme , thermostability , antibody , biology , amino acid , immunology , medicine , organic chemistry , dna , receptor , disease , adsorption , alzheimer's disease
Hyperglycaemia triggers increased production of methylglyoxal which can cause gross modification in proteins’ structure vis-a-vis function though advanced glycation end products (AGEs). The AGEs may initiate vascular and nonvascular pathologies. In this study, we have examined the biochemical and biophysical changes in human IgG under normal and high glucose after introducing methylglyoxal into the assay mixture. This non-enzymatic reaction mainly engaged lysine residues as indicated by TNBS results. The UV results showed hyperchromicity in modified-IgG samples while fluorescence data supported AGEs formation during the course of reaction. Shift in amide I and amide II band position indicated perturbations in secondary structure. Increase carbonyl content and decrease in sulfhydryl suggests that the modification is accompanied by oxidative stress. All modified-IgG samples showed more thermostability than native IgG; the highest Tm was shown by IgG-high glucose-MGO variant. Results of ANS, Congo red and Thioflavin T dyes clearly suggest increase in hydrophobic patches and aggregation, respectively. SEM and TEM images support aggregates generation in modified-IgG samples.