Conformational change in proteins

Figure 26. An electric (ionic) pulse arrives from the brain through a nerve to the muscle, where it triggers conformational changes in proteins and chemical reactions. All the processes are three-dimensional. The generator (brain) is at the same time an ionic conductor. (Reprinted from T. F. Otero in Polymer Sensors and Actuators, Y. Osada and D. De Rossi, eds., Fig. 1, p., 19. Copyright 19XX. Reprinted with permission of Springer-Verlag.)...

F. X. Schmid, Spectral methods of characterizing protein conformation and conformational changes, in Protein Structure—A Practical Approach (T.E. Creighton, ed.), IRL Press, Oxford, 1989, pp. 251-285. 

Chowdhury, S. K. Katta, V. Chait, B. T. Probing conformational-changes in proteins by mass spectrometry. I. Amer. Chem. Soc. 1990,112, 9012-9013. 

R. Lindeman and G. Zundel, Proton transfer in and polarizability of hydrogen bonds coupled with conformational changes in proteins. II. IR investigation of polyhistidine with various carboxylic acids, Biopolymers 17, 1285-1301 (1978). 

Phosphorescence Lifetimes to Measure Conformational Changes in Proteins... 

Phosphorescence is readily detectable from most types of proteins at room temperature. Tryptophan phosphorescence lifetimes and yields are very sensitive to environment, and therefore phosphorescence is sensitive to conformational changes in proteins. Fundamental questions concerning exactly what parameters affect lifetime and spectra of tryptophan in proteins remain still to be answered. 

Several other successful applications of the low-temperature procedure to the thermal control and analysis of multistep enzyme reactions could be described. We prefer to cite appropriate papers (Douzou, 1974, 1977a,b Fink, 1976a) and to discuss two important problems raised by the present procedure, namely the validity of data obtained in such bizarre media and the necessity of obtaining suitable data on the conformational changes in proteins during their reaction pathways. 

Katta, V., Chait, B. T. Conformational-changes in proteins probed by hydrogen-exchange electrospray-ionization mass-spectrometry. Rapid Commun Mass Spectrom 1991, 5, 214-217. 

The decisive element in exocytosis is the interaction between proteins known as SNAREs that are located on the vesicular membrane (v-SNAREs) and on the plasma membrane (t-SNAREs). In the resting state (1), the v-SNARE synaptobrevin is blocked by the vesicular protein synaptotagmin. When an action potential reaches the presynaptic membrane, voltage-gated Ca "" channels open (see p. 348). Ca "" flows in and triggers the machinery by conformational changes in proteins. Contact takes place between synaptobrevin and the t-SNARE synaptotaxin (2). Additional proteins known as SNAPs bind to the SNARE complex and allow fusion between the vesicle and the plasma membrane (3). The process is supported by the hydrolysis of GTP by the auxiliary protein Rab. 

Amino acids do not give any very useful ultraviolet absorption spectra unless they possess aromatic groups as in phenylalanine, tryptophan, and tyrosine. The absorption characteristics of these groups are more useful in monitoring chemical and conformational changes in proteins than they are in the simple amino acids. 

Norde W, Giacomelli CE (1999) Conformational changes in proteins at interfaces from solution to the interface, and back. Macromol Symp 145 125-136... 

Fig. 8. Schematic representation of protein-mediated cell adhesion on biomaterial surfaces. Biomaterial surface properties (such as hydrophilicity/hydrophobicity, topography, energy, and charge) affect subsequent interactions of adsorbed proteins these interactions include but are not limited to adsorbed protein type, concentration, and conformation. Changes in protein-surface interactions may alter accessibility of adhesive domains (such as the peptide sequence arginine-glycine-aspartic acid) to cells (such as osteoblasts, fibroblasts, or endothelial cells) and thus modulate cellular adhesion. (Adapted and redrawn from Schakenraad, 1996.)...

The advantages of ESI-MS for studying conformational changes in proteins were recognized by Katta and Chait in 1991.31 ESI-MS is used not only to distinguish between native (folded) proteins and denatured (unfolded) proteins but also to follow the dynamics of the protein (un)folding process. In one case, an interesting conformational phenomenon that went unnoticed... 

Hammarstrom, P., Owenius, R., Martenson, L-G., Carlsson, U., and Lindgren, M. (2001) High resolution probing of local conformational change in proteins by the use of multiple labeling unfolding and self -assembly of human carbonic anhydrase II monitored by spin, fluorescent, and chemical reactivity probs, Biophys. J. 80, 2867-2885. 

Lumry, R. and Eyring, H. (1954) Conformational changes in proteins, J. Phys. Chem. 58, 110-120. 

Prestrelski, S. J., Tedeschi, N., Arakawa, T., and Carpenter, J. F. (1993), Dehydration-induced conformational changes in proteins and their inhibition by stabilizers, Biophys. J., 65, 661-671. 

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