The Molecular Switching Mechanism at the Conserved D(E)RY Motif in Class-A GPCRs.

The disruption of ionic and H-bond interactions between the cytosolic ends of transmembrane helices TM3 and TM6 of class-A (rhodopsin-like) G protein-coupled receptors (GPCRs) is a hallmark for their activation by chemical or physical stimuli. In the bovine photoreceptor rhodopsin, this is accompanied by proton uptake at Glu(134) in the class-conserved D(E)RY motif. Studies on TM3 model peptides proposed a crucial role of the lipid bilayer in linking protonation to stabilization of an active state-like conformation.

Conjugated estrogens and tibolone modify the gonadotrophin glycosylation pattern in postmenopausal women.

Objective: The purpose of this study was to evaluate the changes in the percentage of glycosylation of FSH and LH when using conjugated estrogens and tibolone as hormonal therapy (HT) in postmenopausal compared with regular menstrual cycles.

Design: The study had three groups, with 10 participants in each group. The control group consisted of 10 women with normal menstrual cycles, a second group with 10 postmenopausal patients who received conjugated estrogens (Premarin 0.