The Moonlighting Function of Soybean Disordered Methyl-CpG-Binding Domain 10c Protein

Area of Science:

• Biochemistry
• Molecular Biology
• Plant Science

Background:

• Intrinsically disordered proteins (IDPs) exhibit multifunctionality by adapting structures to environmental cues.
• Methyl-CpG-binding domain (MBD) proteins, particularly their disordered regions, are crucial for interpreting DNA methylation in growth and development.
• The stress-protective roles of MBD proteins remain largely unexplored.

Purpose of the Study:

• To investigate the structural characteristics and stress-protective functions of soybean GmMBD10c protein.
• To determine if GmMBD10c exhibits moonlighting activities beyond its known MBD functions.

Main Methods:

• Bioinformatic prediction, circular dichroism, and nuclear magnetic resonance (NMR) spectroscopy were used to analyze protein structure.
• Enzyme activity assays and SDS-PAGE were employed to assess GmMBD10c's ability to prevent protein misfolding and aggregation.
• Salt tolerance assays in *Escherichia coli* were conducted to evaluate GmMBD10c's stress-protective effects.

Main Results:

• GmMBD10c was predicted to be nuclear and found to be partially disordered.
• GmMBD10c exhibited protective activity against freeze-thaw and heat-induced misfolding and aggregation of proteins, including lactate dehydrogenase.
• Overexpression of GmMBD10c significantly enhanced salt tolerance in *Escherichia coli*.

Conclusions:

• Soybean GmMBD10c is a moonlighting protein with demonstrated stress-protective functions.
• GmMBD10c's ability to prevent protein aggregation highlights its potential role in cellular stress response.
• The findings expand the known functions of MBD proteins, suggesting broader roles in cellular protection.