Polyalanine

Polyalanine is a polymer composed of repeating alanine residues. It can refer to synthetic polymers such as poly-L-alanine, as well as to natural homopolymeric runs of alanine within proteins, commonly called polyalanine tracts.

In synthetic chemistry, poly-L-alanine is typically prepared by polymerizing the alanine N-carboxyanhydride or related protected derivatives, using ring-opening polymerization. The resulting polymer is a polyamide with a simple methyl-bearing side chain that influences its conformational preferences.

The alanine side chain favors hydrophobic interactions and the polymer tends to adopt alpha-helical conformations; as a result, polyalanine samples can be relatively rigid and may crystallize depending on chain length, tacticity, and processing conditions.

In biology, runs of consecutive alanine residues occur in various proteins, especially transcription factors. Expansions of these tracts beyond normal lengths are linked to developmental and neuromuscular disorders, including congenital central hypoventilation syndrome and oculopharyngeal muscular dystrophy, among others.

Applications and research: Polyalanine-containing materials are studied as biodegradable biomaterials, scaffolds, and as model systems for protein folding and helix formation.