Structural insights into SETD3-mediated histidine methylation on β-actin

Area of Science:

• Biochemistry
• Structural Biology
• Molecular Biology

Background:

• SETD3 is a SET domain protein involved in key cellular processes.
• SETD3 functions as an actin-specific methyltransferase, targeting His73 on beta-actin.
• Protein histidine methylation is a crucial post-translational modification.

Purpose of the Study:

• To elucidate the structural basis and catalytic mechanism of SETD3-mediated beta-actin methylation.
• To investigate the conformational changes involved in SETD3-beta-actin interaction.
• To provide insights for the development of SETD3 inhibitors.

Main Methods:

• X-ray crystallography to determine structures of SETD3-beta-actin peptide complexes.
• Biochemical experiments and enzyme activity assays.
• Analysis of protein-protein interactions and conformational dynamics.

Main Results:

• Two structures of SETD3 bound to S-adenosyl-L-homocysteine and either unmodified or methylated beta-actin peptide were determined.
• SETD3 exhibits high sequence specificity in recognizing and methylating beta-actin.
• Significant conformational changes occur in both SETD3 and beta-actin upon binding.

Conclusions:

• This study provides the first structural insights into the catalytic mechanism of SETD3-mediated histidine methylation on beta-actin.
• The findings advance the understanding of protein histidine methylation.
• The results facilitate the rational design of small molecule inhibitors targeting SETD3.