(H2N-(Me)2C-COOH) or alpha-methyl-alanine.
Aib is an alpha amino acid that occurs in paptidic antibiotics (for example alamethicin) produced by microbial organisms. It is not one of the proteinogenic amino acids and rather rare in nature.
Aib is a strtong helix inducer in peptides. Oligomers of Aib form 3-10 helices.