FIGURE 2.

Structural and functional characterization of the TM3 of CRF₁R. A, inhibition of specific ¹²⁵I-Tyr⁰-sauvagine binding to MTSEA-insensitive CRF₁R mutant (ΔCys) or its substituted Cys mutants after their reaction with MTSEA is represented by bars, which indicate the mean ± S.E. values from 3 to 32 independent experiments. Negative inhibition means potentiation of radioligand binding after MTSEA reaction. Solid bars with asterisks indicate substituted Cys mutants for which inhibition/potentiation was significantly different from ΔCys (p < 0.05; one way ANOVA). B, binding affinities (−logK_D) of ¹²⁵I-Tyr⁰-sauvagine for the ΔCys CRF₁R (ΔCys) and its substituted Cys mutants (ΔCys + R189^3.26C to ΔCys + G210^3.47C) are represented as bars, which indicate the mean ± S.E. values from 3 to 7 independent experiments. Solid bars with asterisks indicate substituted Cys mutants for which ¹²⁵I-Tyr⁰-sauvagine binding affinity was significantly different from that for ΔCys (p < 0.05; one way ANOVA).