Characterization of Agonist Binding to His524 in the Estrogen Receptor alpha Ligand Binding Domain

• The bioactivities of the natural steroidal estrogen 17 beta-estradiol (E-2), the synthetic estrogen diethylstilbestrol (DES), and the phytoestrogen genistein (GEN) are intimately associated with their binding to the estrogen receptor alpha ligand binding domain (ER alpha LBD) and accordingly allostery. Molecular modeling techniques have been performed on agonists in complex with the LBD, focusing on the pivotal role of His524 modeled as the epsilon-tautomer and the protonated form (depending on pH). It is found that E-2 binds to the active LBD with the aid of Leu525, showing existing stable patterns of an H-binding network with Glu419 via His524 in all models. The main difference seen in the effect is that the full agonists E-2 and DES have higher binding energies to the protonated His524 than the partial agonists GEN and Way-169916 (W), which is in line with noted experimental transcriptional activities. In conclusion, the study demonstrates that the phytoestrogen GEN interacts differently with the LBD than what E-2 and DES do, which explains the observed signaling differences.

Ämnesord

NATURVETENSKAP  -- Kemi -- Fysikalisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Physical Chemistry (hsv//eng)

NATURVETENSKAP  -- Kemi -- Teoretisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Theoretical Chemistry (hsv//eng)

NATURVETENSKAP  -- Kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences (hsv//eng)

Nyckelord

Allostery

Estrogen receptor

Genistein

H-binding

In-line

Ligand binding domain

Molecular modeling techniques

Phytoestrogenes

Protonated

Stable patterns

Steroidal estrogens

Transcriptional activity

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