Figure 2.

Schematic representation of the 22‐mer C/C/B‐β₁ cyclopeptide mimicking the human β₁EC_II bearing the essential motif of the clinically relevant auto‐epitope: circles with capitals specify amino acids (single letter code). Numbers specify their position in the sequence of the human β₁‐AR. ‘B' stands for the artificial amino acid α‐aminobutyrate substituting C²¹⁶ in order to prevent a non‐physiological S‐S‐bond C²⁰⁹↔C²¹⁶. Boxed letters N and C indicate the termini of the predicted β₁EC_II loop. The full line between C²⁰⁹ and C²¹⁵ indicates the essential intra‐loop disulfide bridge; black circles depict amino acid residues essential for the neutralization of stimulating rodent anti‐β₁EC_II‐abs. Grey circles represent additional amino acid residues supposed to be relevant for the neutralization of stimulating human anti‐β₁EC_II‐aabs. Amino acid residues R²⁰⁷, E²⁰⁵, S²⁰³, and T²²⁰ were not found essential by directed mutational analysis.