FIGURE 6.

Biological activities and cross-linking of Ste2p K269A, K269C, and K269H mutants. A, growth inhibition induced by α-factor. Different amounts (0.25–4.0 μg) of α-factor were spotted on filter disks on a lawn of cells. The images of the plates shown were taken after 16 h. B, induction of transcription of the FUS1 gene was carried in the absence or presence of 1 μm α-factor. The percentages of β-galactosidase activity of the various mutants were determined by normalizing with the wild type (100%). C, binding affinity of Ste2p mutants analyzed by saturation binding with tritium-labeled α-factor. Both mutants displayed binding affinity similar to wild type. D, immunoblot images of Bio-DOPA¹-α-factor cross-linking into Ste2p K269A, K269C, and K269H mutants. Purified Ste2p-Bio-DOPA¹-α-factor cross-linked samples were resolved on 10% SDS-PAGE and probed with anti-FLAG and Na-HRP. Error bars, S.E.