Structural investigation of Rett-inducing MeCP2 mutations.

Area of Science:

• Structural biology
• Molecular genetics
• Neuroscience

Background:

• Rett syndrome (RTT) is a neurodevelopmental disorder associated with mutations in the methyl-CpG binding protein 2 (MeCP2).
• MeCP2 contains intrinsically disordered regions (IDPs) and structured domains, including the methyl-CpG binding domain (MBD) and transcription repressor domain (TRD), crucial for its function.
• Understanding the structure-function relationship of MeCP2 is vital for elucidating RTT pathogenesis.

Purpose of the Study:

• To determine the X-ray structure of the MBD of MeCP2.
• To rationalize the location and pathogenicity of mutations associated with Rett syndrome.
• To investigate the role of specific amino acid residues and protein dynamics in MeCP2-DNA interactions.

Main Methods:

• X-ray crystallography to determine the 3D structure of the MeCP2 MBD.
• Analysis of mutation sites within the MBD structure.
• Biophysical and biochemical assays to assess protein-DNA binding affinity and kinetics (implied).

Main Results:

• The X-ray structure defines the spatial distribution of most RTT-associated mutation sites within the MBD.
• Mutations of positively charged amino acids at the protein-DNA interface reduce MeCP2-DNA adduct stability.
• Proline substitutions, even outside the direct DNA-binding interface, can affect MeCP2's conformational states and activity.

Conclusions:

• The MBD structure provides a framework for understanding RTT mutations.
• Protein-DNA interaction stability is sensitive to charge at the interface, and proline's role in conformational dynamics is critical for MeCP2 function.
• These findings may extend to other DNA-binding IDPs and their associated diseases.