Tracking Proteins in the Cell’s Powerhouse

A labeling and electroporation workflow brings high-resolution NMR into intact organelles

October 13, 2026
3 min

The Analytical Scientist

Overview

Researchers developed an NMR spectroscopy method to examine labeled proteins inside intact, isolated mitochondria. The approach detected protein structure, membrane interactions, stability, and binding differences in the organelle environment, including findings for alpha-synuclein and GB1.

Background

Mitochondrial dysfunction has been linked to cancer, inflammation, aging, and neurodegenerative diseases. Protein behavior measured in purified laboratory solutions may not reflect behavior inside mitochondria. The reported method introduces labeled proteins into isolated mitochondria and uses NMR to study them in that compartment. The experiments used isolated mitochondria and temperatures below physiological conditions, and sample viability was limited.

Data Highlights

Protein or measure	Finding
Mitochondrial integrity and function	Membrane-potential and enzyme-activity tests indicated that mitochondria remained intact and functional after electroporation.
Alpha-synuclein	It remained largely disordered; NMR signal changes indicated interaction between its N-terminal region and mitochondrial membranes.
A30P alpha-synuclein	The variant associated with inherited Parkinson’s disease showed weaker membrane interactions than unmodified alpha-synuclein.
Methionine oxidation	Oxidation reduced interaction between alpha-synuclein’s N-terminal region and mitochondrial membranes.
GB1 stability	GB1 was more stable inside mitochondria than in laboratory buffer.
GB1-variant binding	Binding affinity between two copies of a GB1 variant was approximately twice as high inside mitochondria as in buffer.

Key Findings

The method used nitrogen-15 and fluorine-19 labeling to study alpha-synuclein and the folded proteins GB1, ubiquitin, and KH1 inside isolated mitochondria.
Selective labeling reduced overlapping signals, and fluorine-19 provided sensitive measurements with little interference from naturally occurring biological molecules.
Control experiments indicated that most measured signals came from proteins inside mitochondria rather than proteins leaked into the surrounding solution.
Alpha-synuclein remained largely disordered, while its N-terminal region interacted with mitochondrial membranes.
The A30P variant showed weaker membrane interactions than unmodified alpha-synuclein, and methionine oxidation also reduced the N-terminal region’s membrane interaction.
GB1 was more stable and a GB1-variant pair bound more strongly inside mitochondria than in buffer; the researchers suggested molecular crowding and interactions with mitochondrial components as possible explanations for the stability result.

Clinical Implications

The method may support investigation of protein behavior and molecular processes associated with mitochondrial disease in a more biologically relevant setting. The study did not assess disease progression or patient outcomes, and its isolated-mitochondria conditions and limited sample viability constrain interpretation of slower processes.

Conclusion

NMR measurements in isolated mitochondria revealed differences in protein membrane interactions, stability, and binding compared with laboratory buffer. Further work is needed to improve sensitivity and sample viability and to examine additional proteins and disease models.