Solubilization and disaggregation of polyglutamine peptides.

Area of Science:

• Biochemistry
• Molecular Biology
• Neuroscience

Background:

• Polyglutamine peptides longer than Q20 are typically insoluble in aqueous solutions.
• Insolubility hinders the study of polyglutamine aggregation, a key factor in neurodegenerative diseases.
• Existing methods are insufficient for preparing soluble, aggregation-prone polyglutamine peptides.

Purpose of the Study:

• To develop a reliable method for dissolving and disaggregating chemically synthesized polyglutamine peptides.
• To enable solution-based studies, including in vitro aggregation experiments, on polyglutamine peptides relevant to disease.
• To improve the reproducibility and quantitation of polypeptide aggregation studies.

Main Methods:

• Dissolution of polyglutamine peptides using a mixture of trifluoroacetic acid and hexafluoroisopropanol.
• Evaporation of the solvent mixture to yield soluble polyglutamine peptides.
• Application of the method to peptides up to at least Q44, and to peptides that appear soluble.

Main Results:

• Polyglutamine peptides up to at least Q44 were converted to a readily soluble form in aqueous buffers.
• The procedure effectively removed seeding aggregates from even apparently soluble peptides.
• The method facilitates in vitro aggregation studies on disease-associated polyglutamine lengths.

Conclusions:

• A novel method effectively dissolves and disaggregates chemically synthesized polyglutamine peptides.
• This protocol is essential for studying the aggregation of polyglutamine peptides implicated in Huntington's Disease and related disorders.
• The technique may also enhance the study of aggregation for other polypeptides.