Expression, purification and characterization of TMCO1 for structural studies

Area of Science:

• Biochemistry
• Molecular Biology
• Structural Biology

Background:

• Transmembrane and coiled-coil domains 1 (TMCO1) is vital for cell physiology, with mutations linked to various human diseases.
• TMCO1 functions as an endoplasmic reticulum (ER) calcium release channel, preventing ER calcium overload and maintaining calcium homeostasis.
• The structural basis of TMCO1's function remained largely unknown.

Purpose of the Study:

• To elucidate the molecular structure of the TMCO1 channel.
• To understand the structural underpinnings of TMCO1's role in calcium homeostasis.

Main Methods:

• Screening of TMCO1 expression in Escherichia coli and insect cell systems.
• Purification of recombinant Dictyostelium discoideum TMCO1 (DdTMCO1) using affinity and size exclusion chromatography.
• Solution Nuclear Magnetic Resonance (NMR) spectroscopy of DdTMCO1 in DPC micelles.

Main Results:

• High-yield expression of DdTMCO1 achieved in Escherichia coli.
• Successful purification of the recombinant TMCO1 protein.
• Solution NMR analysis revealed three α-helical transmembrane regions within DdTMCO1.

Conclusions:

• The study provides the first structural insights into TMCO1, identifying key transmembrane helical domains.
• These findings lay the groundwork for understanding TMCO1's mechanism as a calcium release channel.
• Further structural and functional studies of TMCO1 are warranted to fully elucidate its role in cellular calcium regulation and disease.