The deduced amino acid sequence and topology of amorph RhCe from the 2 Rh_null patients. (A) Comparison of the sequence between the normal (residues 251-417) and putative amorph RhCe protein (residues 251-398). The frameshift starts from Pro₃₂₃ (marked by a star) and the new stretch of 76 amino acids terminates at Gly₃₉₈ (bold). (B) Topology and organization of the putative amorph protein in the membrane. The amorph protein lacks the last 2 TM domains and does not express any Rh antigens, although it contains C and e antigen-specific polymorphisms, Ser₁₀₃ and Ala₂₂₆, on the second and fourth exofacial loops. (C) Immunoblot analysis of Rh30(D) and Rh50 proteins in the Rh_null membrane. The upper panel was probed with antibody LOR-15C9 and the lower one with 2D10. Lane designations are as in Fig 1. Note that no RhD protein was detected in D-negative and Rh_null patients, as expected. In contrast, a significant amount of Rh50 protein was present in the Rh_null cells.