Oviduct progesterone receptor: physical and chemical studies.
Chicken oviduct progesterone receptor has been purified to homogeneity. The protein consists of two dissimilar hormone-binding subunits, A and B, present in equal amounts in the complex. They have molecular weights of 79,000 and 108,000, respectively, as shown by both SDS-gel electrophoresis of the purified proteins and photoaffinity labeling of both with a labeled synthetic progestin. The two subunits show considerable homology (or identity) of structure at the hormone-binding domain, located at the N-terminus of the proteins. Considerable divergence of sequence must exist elsewhere in A and B, as shown by tryptic peptide mapping and by the fact that subunit A has a strong DNA-binding site lacking in B. Both are phosphorylated in vitro by cAMP-dependent protein kinase; this phosphorylation appears to be responsible for creation of a second, weaker progesterone-binding site on each subunit.
D000818:Animals; D001665:Binding Sites; D055598:Chemical Phenomena; D002621:Chemistry; D002645:Chickens; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D010057:Oviducts / Q000032:analysis*; D010750:Phosphoproteins; D011980:Receptors, Progesterone / Q000302:isolation & purification*
D010750:Phosphoproteins; D011980:Receptors, Progesterone