Protein interaction patterns in different cellular environments are revealed by in-cell NMR

Area of Science:

• Biophysics
• Molecular Biology
• Structural Biology

Background:

• In-cell NMR provides atomic-level insights into biomolecules within their native cellular context.
• Soluble proteins can undergo specific (functional) or non-specific (general) interactions within cells, often leading to signal loss in NMR.
• Understanding these interactions is crucial for interpreting in-cell NMR data.

Purpose of the Study:

• To develop a strategy for recovering lost in-cell NMR signals from soluble proteins.
• To differentiate between specific and non-specific cellular interactions affecting protein NMR signals.
• To expand the utility of in-cell NMR for studying a broader range of proteins.

Main Methods:

• Utilized in-cell Nuclear Magnetic Resonance (NMR) spectroscopy.
• Introduced mutations into the human protein profilin 1 as a model system.
• Compared NMR signal recovery patterns in human and bacterial cells.

Main Results:

• Mutations successfully restored in-cell NMR signals for profilin 1.
• Human cells exhibited both specific and non-specific interactions, while bacterial cells showed only non-specific effects.
• The comparative analysis allowed for the assessment of the relative contributions of different interaction types.

Conclusions:

• The developed strategy enables the detection of in-cell NMR spectra for soluble proteins without compromising their native fold.
• This approach significantly enhances the applicability of in-cell NMR to diverse protein systems.
• Distinguishing interaction types provides deeper insights into protein behavior in cellular environments.