Structure conformational change

Norregaard, L. and Gether, U. (2001) The monoamine neurotransmitter transporters structure, conformational changes and molecular gating. Curr. Opin. DrugDiscov. Dev. 4,591-601. 

More advanced semiempirical molecular orbital methods have also been used in this respect in modeling, e.g., the structure of a diphosphonium extractant in the gas phase, and then the percentage extraction of zinc ion-pair complexes was correlated with the calculated energy of association of the ion pairs [29]. Semiempirical SCF calculations, used to study structure, conformational changes and hydration of hydroxyoximes as extractants of copper, appeared helpful in interpreting their interfacial activity and the rate of extraction [30]. Similar (PM3, ZINDO) methods were also used to model the structure of some commercial extractants (pyridine dicarboxylates, pyridyloctanoates, jS-diketones, hydroxyoximes), as well as the effects of their hydration and association with modifiers (alcohols, )S-diketones) on their thermodynamic and interfacial activity [31 33]. In addition, the structure of copper complexes with these extractants was calculated [32]. 

Only a few molecular orbital calculations regarding the structures, conformational changes and bonding of S molecules have been published. Fimdamental reactions of sulfur rings like interconversions are only poorly understood, and more examples for the formation of homocyclic derivatives directly from the corresponding S parent molecules are likely to be found. These few comments show that much more work has to be done before the chemistry of elemental sulfur can be regarded as well known . 

While we tend to think of proteins as having fixed structures, conformational changes are basic to life. Many proteins are very flexible and in part disordered.6553 At the same time proteins can be misfolded leading to amyloid formation (Box 29-E) and to other diseases.65513-6... 

It is possible that the structural conformational change produced in transfer of the maltotriosyl moiety induces glucosidase action. The effect of mildly denaturing conditions on the coordination of the two activities might suggest this. 

A large family of therapeutically relevant membrane receptors is the seven-transmembrane receptor family, so named because of their structure. Conformational changes in this protein induced by intracellular and extracellular ligands permit information transfer from the outside to the inside of the cell. When these receptors become activated, they bind... 

The desorption of the included guest occurs readily and there is no significant hysteresis. In marked contrast to the case of hydrogen-bonded host 29 (Fig. 16), there is no significant structural/conformational change in the host network upon sorption/desorption of the guest. This is taken as another sort of evidence for the robustness of metal-coordination networks. 

Interest in electric field effects on macromolecules was appreciably revived when it was found that electric fields are capable of producing structural-conformational changes in biopolymers and membranes. Here, too, optical properties are a convenient indicator of field-induced processes. Initial hints of presumably chemical contributions to field-induced changes in birefringence were reported for DNA solutions of low ionic strength. Dielectric measurements have shown that polypeptides in viscous organic solvents may undergo intramolecular helix-coil transitions in the presence of electric fields. In the meantime there are many reports on field-... 

The Forster-type resonance energy transfer (FRET) has become a common practice in the study of macromolecular structures, conformational changes, in vitro and cellular complex formation, and so on [15]. Ullman introduced its use for clinical diagnostics as a way to make homogeneous immunoassays [16]. 

For complex molecules (e.g., proteins) the temperature change may lead not only to changes in the Boltzmann distribution of molecules over the energy levels, but also to changes in the protein structure. Conformational changes could influence the profiles of potential wells characterizing the pro-... 

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