FIG. 2.

Domain organization of the Aer protein showing residue substitutions, N-terminal deletions, and associated phenotypes. All missense mutations, except for T12C, were identified by mutagenesis of pGH1. Aer-T12C was identified during cysteine substitution experiments. Mutant Aer proteins that were phenotypically rescued in the Δaer Δtsr strain BT3312 are indicated in roman type, while mutant proteins that were not phenotypically rescued are underlined and italicized. An asterisk (Aer[20-506]*) indicates that a glycine codon was added before codon 20 in this construct, as explained in Materials and Methods. The phenotypes listed indicate behavior in a temporal oxygen gradient for the receptorless strain BT3388, expressing the mutant Aer proteins. Abbreviations: TM, transmembrane domain; PS, proximal signaling region; HCD, highly conserved domain.