A connector of a helical coiled coil-type structure connecting a first and a second molecule, wherein the first molecule comprises a peptidic first alpha-helix and the second molecule comprises a peptidic second alpha-helix, which second alpha-helix is coiled to the first alpha-helix. The first alpha-helix comprises a C-terminal region consisting of a repeat of an amino acid motif a-x1 and the C-terminal motif a-x1-x2, or an N-terminal region consisting of a repeat of an amino acid motif x1-a and the N-terminal motif x2-x1-a, where a is a motif sequence of 4-8 amino acids, x1 is Lysine, and x2 is an extension of the motif. The extension consists of 1-10 amino acids and does not comprise more than 4 consecutive amino acids incorporated in said motif a-x1 or x1-a. In a multimeric protein, two polypeptide chains can be connected to each other by such connector.