Fmoc-Pro-OH Interaction of the D ring on estradiol

Fig. 3C also shows that Cε2 on Phe-339 is 1.4Å from C2 on estradiol, which is a very unfavorable van der Waals contact. Cδ2 on Tyr-447 has moved to 4Å from the C17 hydroxyl. In octopus ER2, Nη2 moved to 3.8Å from the C3-phenolic group, which is too distant for a hydrogen bond. Moreover, Nε is