Receptor sites, membrane

When d-tubocurarine binds at the acetylcholine receptor site membrane. This prevents a nerve impulse, and results in paralysis. 

There are three advantages to study molecular recognition on surfaces and interfaces (monolayers, films, membranes or soHds) (175) (/) rigid receptor sites can be designed (2) the synthetic chemistry may be simplified (J) the surface can be attached to transducers which makes analysis easier and may transform the molecular recognition interface to a chemical sensor. And, which is also a typical fact, this kind of molecular recognition involves outside directed interaction sites, ie, exo-receptor function (9) (see Fig. 5b). 

Other auxin-like herbicides (2,48) include the chlorobenzoic acids, eg, dicamba and chloramben, and miscellaneous compounds such as picloram, a substituted picolinic acid, and naptalam (see Table 1). Naptalam is not halogenated and is reported to function as an antiauxin, competitively blocking lAA action (199). TIBA is an antiauxin used in receptor site and other plant growth studies at the molecular level (201). Diclofop-methyl and diclofop are also potent, rapid inhibitors of auxin-stimulated response in monocots (93,94). Diclofop is reported to act as a proton ionophore, dissipating cell membrane potential and perturbing membrane functions. 

Figure S.21 The hemaggiutinin moiecuie is formed from three subunits. Each of these subunits Is anchored In the membrane of the influenza vims. The globular heads contain the receptor sites that bind to sialic acid residues on the surface of eukaryotic cells. A major part of the subunit interface is formed by the three long intertwining helices, one from each subunit. (Adapted from I. Wilson et al.. Nature 289 366-373, 1981.)...

After initial experiments demonstrating that the antiserum was capable of completely inhibiting the binding of [ H]PbTx-3 to its receptor site in rat brain membranes (Figure 9), we began studies designed to evaluate potential of the antiserum for prophylaxis and treatment of brevetoxin intoxication (34). The tethered rat model was used, and surgical implantations were identical to those described above. Heart rate, core and peripheral body temperatures, lead VIO ECG, and arterial blood pressure were monitored continuously. Respiratory rate was recorded each 5 min for the first 3 hr, then each 15 min until 6 hr. 

Figure 9. Anti-PbTx antiserum inhibition of [ H]PbTx-3 binding to its receptor site in rat brain membrane preparations. Labeled toxin (0.5 nM in 1 ml PBS) was incubated with rat brain membranes (125 fig total protein) and increasing amounts of anti-PbTx antiserum (- -) or pre-immune serum (- -) for 1 hr at 4 C. Membrane-bound radioactivity was then measured in a centrifugation assay as previously described (8),...

Heidmann, T. Oswald, R.E. and Changeux, J.-P. Multiple sites of action for noncompetitive blockers on acetylcholine receptor rich membrane fragments from Torpedo marmorata. Biochemistry 22 3112-3127, 1983. 

In general, virus receptors carry out normal functions in the cell. For example, in bacteria some phage receptors are pili or flagella, others are cell-envelope components, and others are transport binding proteins. The receptor for influenza vims is a glycoprotein found on red blood cells and on cells of the mucous membrane of susceptible animals, whereas the receptor site of poliovirus is a lipoprotein. However, many animal and plant viruses do not have specific attachment sites at all and the vims enters passively as a result of phagocytosis or some other endocytotic process. 

Neuropeptide receptors are not confined to synaptic regions. Peptidergic neurotransmission often operates on a slower time scale than conventional neurotransmitters, so it is not surprising that peptide receptors are often localized at a distance from the synapse. For example, although some substance P terminals contact membranes loaded with substance P receptor, only a small fraction of the substance P receptor-laden membrane is apposed to synaptic terminals. Substance P may diffuse a considerable distance from its release site and still find a receptor with which it can interact [21]. 

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