Analysis of Heterodimeric "Mutual Synergistic Folding"-Complexes

Area of Science:

• Protein structure and dynamics
• Biochemistry and molecular biology

Background:

• Intrinsically disordered proteins (IDPs) can form stable structures via Mutual Synergistic Folding (MSF).
• The MFIB database compiles information on MSF complexes.
• Previous work analyzed homodimeric MSF complexes.

Purpose of the Study:

• Analyze heterodimeric MSF complexes.
• Investigate the driving forces behind heterodimeric MSF complex stabilization.
• Compare amino acid composition of MSF complexes with globular proteins.

Main Methods:

• Analysis of heterodimeric MSF complexes from the MFIB database.
• Comparison of amino acid composition between MSF and globular proteins (monomeric and dimeric).
• Evaluation of inter-subunit interactions and structural features.

Main Results:

• Heterodimeric MSF monomer subunits show slight divergence from globular proteins.
• MSF heterodimeric complexes exhibit amino acid compositions closer to globular complexes post-dimerization.
• Inter-subunit interactions are strengthened, with backbone shielding, core formation, and energetic gains contributing to stability.

Conclusions:

• Mutual Synergistic Folding in heterodimers is driven by multiple factors beyond backbone shielding.
• Formation of a buried structural core and strengthened inter-subunit interactions stabilize these complexes.
• MSF complexes represent a unique class of proteins with distinct folding mechanisms.