Related Experiment Video
Updated: May 22, 2026

Modification and Functionalization of the Guanidine Group by Tailor-made Precursors
Published on: April 27, 2017
Combined QM/MM study of thyroid and steroid hormone analogue interactions with αvβ3 integrin
Marek Freindorf1, Thomas R Furlani, Jing Kong
1Center for Computational Research, State University of New York at Buffalo, Buffalo, NY 14260, USA.
Abstract:
Recent biochemical studies have identified a cell surface receptor for thyroid and steroid hormones that bind near the arginine-glycine-aspartate (RGD) recognition site on the heterodimeric αvβ3 integrin. To further characterize the intermolecular interactions for a series of hormone analogues, combined quantum mechanical and molecular mechanical (QM/MM) methods were used to calculate their interaction energies. All calculations were performed in the presence of either calcium (Ca(2+)) or magnesium (Mg(2+)) ions. These data reveal that 3,5'-triiodothyronine (T(3)) and 3,5,3',5'-tetraiodothyroacetic acid (T(4)ac) bound in two different modes, occupying two alternate sites, one of which is along the Arg side chain of the RGD cyclic peptide site. These orientations differ from those of the other ligands whose alternate binding modes placed the ligands deeper within the RGD binding pocket. These observations are consistent with biological data that indicate the presence of two discrete binding sites that control distinct downstream signal transduction pathways for T(3).
Related Concept Videos
Intracellular Signaling Affects Focal Adhesions
Some...
Activation of Integrins
In "outside-in signaling," external factors in the extracellular space bind to exposed ligand binding sites on integrins. This causes the inactive protein to undergo a conformational change to become active. Integrins are often clustered on the cell membrane. Repetitive and regularly spaced ligand binding events provide an effective stimulus.
Pharmacogenetics of Drug Targets: β₂-Adrenergic Receptors, Apo E, Thymidylate Synthase
Synthesis and Regulation of Thyroid Hormones
Upon reaching the thyroid gland, TSH stimulates the follicular cells' active uptake of iodide ions from the blood. The ions diffuse to the apical surface of the cells and are oxidized to iodine. The iodine is then...
Integrins
Some ECM proteins assemble into a basement membrane to which the remaining components adhere. Proteoglycans typically form the bulk of the ECM while fibrous proteins, like collagen,...
Quantitative Aspects of Drug-Receptor Interaction

