Conformational changes, monitoring

Grunewald, M. and Kanner, B. I. (1995) Conformational changes monitored on the glutamate transporter GLT-1 indicate the existence of two neurotransmitter-bound states../. Biol. Chem. 270,17017-17024. 

Muller D J, Baumeister W and Engel A 1996 Conformational change of the hexagonally packed intermediate layer of Deinococcus radiodurans monitored by atomic force microscopy J. Bactehol. 178 3025... 

Despite its weakness, the anisotropy of the g tensor of iron-sulfur centers can be used to determine the orientation of these centers or that of the accommodating polypeptide in relation to a more complex system such as a membrane-bound complex. For this purpose, the EPR study has to be carried out on either partially or fully oriented systems (oriented membranes or monocrystals, respectively). Lastly, the sensitivity of the EPR spectra of iron-sulfur centers to structural changes can be utilized to monitor the conformational changes induced in the protein by different factors, such as the pH and the ionic strength of the solvent or the binding of substrates and inhibitors. We return to the latter point in Section IV. 

Calleja, V., Ameer-Beg, S. M., Yojnovic, B., Woscholski, R., Downward, J. and Larijani, B. (2003). Monitoring conformational changes of proteins in cells by fluorescence lifetime imaging microscopy. Biochem. J. 372, 33 40. 

The hydrolysis of mant-GTP bound to Ras can be monitored by a slight decrease in fluorescence. Binding experiments of N-Ras with the non-hydro-lyzable GTP-analogue mant-GppNHp showed a biphasic increase in fluorescence. The slow phase had the same amplitude as the decrease observed for the hydrolysis of Ras mant-GTP which led to the hypothesis that a conformational change in the Ras protein proceeds GTP-hydrolysis [170] and represents the rate limiting step ... 

The application of heterobifunctional cross-linkers allows macromolecular PAL to probe protein-protein interactions, including subunit interactions and location, monitoring the conformational changes induced by signal transmission. 

Fig. 4. Time-induced conformational change of spider silk protein (spidroin) in solution. Solutions of silk proteins at 1% w/v in distilled water were monitored using circular dichroism. The graph shows a change in secondary structure with time. The silk proteins underwent a kinetically driven transition from a partially unfolded structure to a -sheet-rich structure (from Dicko et al., 2004c). ( ) after 0 days, (O) after 1 day, and (A) after 2 days. The conformational change appeared faster at 20°C compared to 5°C, suggesting a hydrophobically driven mechanism. (Copyright 2004 American Chemical Society.)...

Characterization of ligand-induced conformational changes in atomic detail has primarily been studied through comparison of high-resolution X-ray structures for macromolecules crystallized in both free and ligand-bound states. The possibility of monitoring such... 

The fact that ET and conformational reactions thus are sequential (Scheme III), and not concerted, is an important factor in efforts to disentangle eonforma-tional and electron-transfer influences, because standard detection methods monitor only the ET event, and not conformational changes within one electronic state. In many, if not most, instances the measured time course of a single gated ET reaction is likely to be indistinguishable from a reaction without gating. 

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