Native membrane proteins vs. yeast recombinant: an example: the mitochondrial ADP/ATP carrier

Area of Science:

• Biochemistry
• Structural Biology
• Mitochondrial Physiology

Background:

• The mitochondrial ADP/ATP carrier (Ancp) is a key protein in energy metabolism.
• Specific inhibitors like carboxyatractyloside (CATR) and bongkrekic acid (BA) stabilize Ancp conformations.
• Previous biochemical studies suggested Ancp functions as a dimer.

Purpose of the Study:

• Determine the high-resolution 3D structure of Ancp.
• Investigate the structural organization and functional quaternary state of Ancp.
• Optimize purification methods for Ancp from natural and engineered sources.

Main Methods:

• Crystallization and X-ray diffraction of bovine Anc1p complexed with CATR.
• Engineering of a yeast Ancp covalent homodimer mutant.
• Comparative analysis of histidine tag length and position for purification yield and quality.

Main Results:

• The first high-resolution (2.2 Å) 3D structure of a mitochondrial carrier was determined, revealing a monomeric state for Ancp.
• A covalent homodimer mutant of yeast Ancp was successfully engineered for further structural studies.
• Histidine tag length and position significantly impact purification efficiency and quality.

Conclusions:

• The high-resolution structure challenges the hypothesized dimeric function of Ancp.
• Engineered homodimers provide a viable approach to study Ancp's quaternary structure.
• Optimized purification strategies are crucial for obtaining high-quality Ancp for structural and functional analyses.