Binding similarity

Two fundamental questions have emerged from these studies, ie, to what extent are agonists and antagonists binding similarly or differendy to the respective receptors, and can inhibitory compounds be developed that are active in vivo in humans as well as in vitro. An oxytocia antagonist that can block premature uterine contractions presents a promising example of the clinical utihty of such stmctures (47). Both linear as well as bicycHc modifications of these hormones also have provided new antagonist stmctures. 

C terminus (ILWEQ), WASp homology 2 (WH2), profilin (PROF), and cyclase-associated protein, domains are all present in fungi, plants, and metazoa. Many of these domains bind similar sites on actin, although they possess different properties with respect to actin polymerization (reviewed in Van Troys et al., 1999). 

The first crystal structure of the LED of the AR in complex with metri-bolone (R1881) was solved by Matias and colleagues in 2000 [38]. The LED has a similar three-dimensional structure to the other agonist-bound steroid receptors, namely the ERa, ERj6 and the PR [38]. The fact that all steroid hormone receptors bind similar hormone response elements (HREs) stands in sharp contrast to the specific activities elicited by application of the steroid... 

Affinity of MIP towards the target analyte should be examined prior to fabrication of the chemosensor. Batch binding assays are used to test selectivity of suitable MIPs. Especially, affinity of MIP to compounds, which are structurally related to the target analyte, should be tested. If MIP binds similarly with these compounds as the template, then cross-reactivity is manifested [156], This effect was exploited for determination of adenine and its derivatives with the use of MIP templated with 9-ethyladenine. Nevertheless, the cross-reactivity, if undesired, can be avoided by suitable sample pretreatment, e.g. by interferant extraction with a supported liquid membrane (SLM) coupled to the MIP-PZ chemosensor. The Fluoropore membrane filter of submicrometre porosity can serve that purpose. That way, this membrane holds interferants, thus eliminating the matrix effect. The SLM-involving determination procedure is cheaper than traditional laborious sample pretreatment used to remove the interfering substances. For instance, caffeine [143] and vanillin [157] in food samples have been determined using this procedure. 

Complexes with other pseudohalide groups, cyanato- NCO and selenocya-nate NCSe, are also described. For the first one, the M — NCO binding (similar to 107) and M — NCO — M (similar to 109) are generally typical [117,122], Side by side with that described above, the fulminate CON and thiofulminate CNS groups can be examined as pseudohalide ligands. The C — M bonds are generally contained in their complexes [117,122],... 

Derive an expression for the concentration of the free drug for one-site drug-protein binding similar to Equation (3.181a). 

Compounds 105b and 105d showed strong RARa agonist binding similar to that of carbon analogues 105a,c, and induced differentiation... 

Related optical and fluorescent sensor systems have been widely used. For instance, the fluorescence of the pyrene unit in species (187) is quenched upon saccharide binding to the boron center. Boronic acid groups were also attached to dendrimers and polymers. The benefit of systems containing at least two boronic acid centers, as shown for the luminescent saccharide sensor (187), is that two-point binding can more effectively control saccharide binding. Similar... 

Structurally diverse compounds like the undecapeptide cyclosporin A and the complex polyketide FK506 bind similar biological target molecules, the immuno-philins, and interfere with identical T cell signaling pathways. 

The coordination of CU3 resembles that in the peroxide form. The threefold coordination by histidines is a very flat trigonal pyramid. The coordination sphere around CU4 is not affected. CU2 is fivefold coordinated to the NE2 atoms of the three histidines, as in the reduced form, and to the two azide molecules. The two azide molecules are terminally bound at the apexes of a trigonal bipyramid. Both azide molecules bind to the copper atom CU2, which is well accessible from the broad channel leading from the surface of the protein to the CU2—CU3 copper pair. It is not unexpected that the second azide molecule (az in Fig. 13) binds similarly to the peroxide molecule, as azide is regarded as a dioxygen analogue. There is no bound azide molecule bridging either CU2 with CU4 or CU3 with CU4. 

The nickel(II) ions can be removed from the above range of macrocyclic complexes and the resulting free ligands can then be converted into iron(II) complexes, which have been shown to exhibit reversible oxygen binding. Similar characteristics have been observed for iron(II) complexes such as (60), which contain bridging from methyl carbon atoms rather than nitrogen atoms. 3 Synthetic information has not been disclosed, but several routes are possible. 

---