A cryo-electron microscopic approach to elucidate protein structures from human brain microsomes

Area of Science:

• Structural Biology
• Neuroscience
• Proteomics

Background:

• Heterogeneous protein samples present challenges for structural determination.
• Cryo-electron microscopy (cryo-EM) is advancing at near-atomic resolution.
• Understanding brain enzyme composition is crucial for neurodegenerative disease research.

Purpose of the Study:

• To apply the novel "Build and Retrieve" cryo-EM method to a human brain microsomal lysate.
• To simultaneously identify and solve structures of multiple enzymes from a complex sample.
• To investigate the structural basis of enzymes involved in critical brain functions.

Main Methods:

• Development and application of the "Build and Retrieve" cryo-EM methodology.
• Analysis of raw human brain microsomal lysate.
• Simultaneous structure determination of multiple proteins.

Main Results:

• Successfully defined the composition of human brain microsomal lysate.
• Identified and solved cryo-EM structures of five distinct brain enzymes.
• These enzymes are involved in neurotransmitter recycling, iron metabolism, glycolysis, axonal development, energy homeostasis, and retinoic acid biosynthesis.
• Malfunction of these enzymes is linked to Alzheimer's, Huntington's, and Parkinson's diseases.

Conclusions:

• The "Build and Retrieve" cryo-EM method enables simultaneous structural analysis of multiple proteins from heterogeneous samples.
• This approach is powerful for tissue and organ proteomics.
• Provides atomic-level insights into enzymes relevant to neurodegenerative disorders.