betaAbetaA1

betaAbetaA1 is a hypothetical synthetic protein variant introduced in educational materials to illustrate modular protein design and beta-sheet folding. The name reflects its construction from two beta-domain modules, designated betaA and betaA1, linked in tandem within a single polypeptide. In conceptual models, betaAbetaA1 is designed to be predominantly beta-sheet rich, with a predicted composition of about 55–65% beta-strands and a smaller proportion of turns and loops. The proposed sequence is designed to minimize long hydrophobic segments outside a hydrophobic core, using alternating hydrophobic and hydrophilic residues to promote sheet formation and a compact fold.

Applications: used as a teaching aid and a test case for protein-design algorithms. It helps illustrate how domain architecture and linker regions influence folding kinetics, stability, and potential misfolding. In purely hypothetical demonstrations, researchers examine how tandem beta-domains interact, how mutations in betaA vs betaA1 modules affect stability, and how linker length modulates cooperativity.

Structure and properties: predicted to form a stable beta-sheet rich topology with a compact core; no known biological function; made for modeling rather than expression in vivo. Research methods applied to simulations include homology modeling, ab initio folding, and molecular dynamics; experimental analogs may include synthetic peptides used to study beta-sheet aggregation, though betaAbetaA1 itself is not reported as produced in living systems.

See also: protein design, beta-sheet, chimeric protein, modular protein architecture.