Characterization of methylglyoxal induced advanced glycation end products and aggregates of human transferrin: Biophysical and microscopic insight

Protein aggregation and glycation is gaining increased attention in recent times as protein aggregates and advanced glycation end products (AGEs) play a pivotal role in many disorders. The purpose of our study was to have an insight into AGEs and aggregates formation of human transferrin (hTF) in the presence of methylglyoxal (MG) employing intrinsic, ANS, Thioflavin T fluorescence, circular dichroism (CD) spectroscopy, docking studies and microscopy. In our study, effect of varying concentration of MG was observed on hTF retorting multispectroscopic, in silico and microscopic approach. Intrinsic fluorescence showed an increase in fluorescence of hTF in presence of MG. The obtained AGEs of hTF in the presence of MG were characterized with respect to fluorescence of AGEs specific adducts. Further, aggregates of hTF were characterized employing ThT fluorescence, transmission electron microscopy (TEM) and fluorescence microscopy. Fluorescence microscopy and TEM confirmed the presence of hTF aggregates in the presence of 50 mM MG; aggregates to be globular in nature. Molecular docking was also employed highlighting the important residues playing a pivotal role in this interaction. Thus, our study characterized the AGEs and aggregates of clinically important protein, hTF; level of MG increases in various pathological conditions giving our study clinical perspective.