Native Ubiquitin Structural Changes Resulting from Complexation with β-Methylamino-l-alanine (BMAA)

Area of Science:

• Biochemistry
• Structural Biology
• Neuroscience

Background:

• Beta-methylamino-l-alanine (BMAA) is a noncanonical amino acid linked to neurodegenerative diseases, but its precise role is unknown.
• Ubiquitin is a crucial protein involved in various cellular processes, and its stability is vital for function.

Purpose of the Study:

• To investigate how BMAA affects the unfolding energy barriers of ubiquitin.
• To determine if BMAA forms a stable complex with ubiquitin and alters its protein dynamics.

Main Methods:

• Ion mobility-mass spectrometry (IM-MS) was used to detect noncovalent complexes between ubiquitin and BMAA.
• Collision-induced unfolding (CIU) was employed to measure the unfolding energy barriers of native ubiquitin and its complexes.

Main Results:

• BMAA forms a noncovalent complex with ubiquitin (Ubq-BMAA).
• The Ubq-BMAA complex exhibits a significantly higher energy barrier to unfolding (requiring >10.5 V) compared to native ubiquitin (8.0–9.0 V).
• This increased stability suggests BMAA may interact with critical binding sites on ubiquitin.

Conclusions:

• BMAA binding enhances the stability of ubiquitin, indicating altered protein dynamics.
• The findings suggest a potential mechanism by which BMAA could contribute to neurodegenerative processes.
• Further research into the Ubq-BMAA interaction is warranted to elucidate its role in disease pathogenesis.