Fig 1.

Sequences of the wild-type and mutant E5 proteins and the transmembrane domain of the PDGF β receptor. The sequence of the transmembrane domain of the wild-type and mutant murine PDGF β receptors is from amino acids 495 to 527. The sequence labeled E5 is the “wild-type” E5 protein containing a proline-to-alanine mutation at position 2 to optimize the Kozak translation initiation sequence. The LRM mutants are E5 mutants isolated from the limited random mutagenesis library. Mutations in the E5 protein and PDGF β receptor are shown in red. Deletions are represented by hyphens. Reflecting the proposed antiparallel orientation of the E5 protein and the PDGF β receptor, the N terminus of the PDGF β receptor segment is at the right, and the N terminus of the E5 protein is at the left. Putative interactions between specific amino acids in the E5 protein and the PDGF β receptor are boxed in green.