Protein folding Temperature jump

At present we are far from an understanding of the protein folding process. Even numerical methods as e.g. molecular dynamics simulations do not lead to realistic predictions. Experiments on the folding process have been performed initially on the millisecond time-scale. It was only recently that new techniques - temperature jump or triplet-triplet quenching experiments - allowed a first access to the nanosecond time domain [2-4]. However, the elementary reactions in protein folding occur on the femto- to picosecond time-scale (femtobiology). In order to allow experiments in this temporal range we developed a new... 

T4 lysozyme 33,497 helix stability of 528, 529 hydrophobic core stability of 533, 544 Tanford j8 value 544, 555, 578, 582-Temperature jump 137, 138, 541 protein folding 593 Terminal transferase 408,410 Ternary complex 120 Tertiary structure 22 Theorell-Chance mechanism 120 Thermodynamic cycles 125-131 acid denaturation 516,517 alchemical steps 129 double mutant cycles 129-131, 594 mutant cycles 129 specificity 381, 383 Thermolysin 22, 30,483-486 Thiamine pyrophosphate 62, 83 - 84 Thionesters 478 Thiol proteases 473,482 TNfn3 domain O-value analysis 594 folding kinetics 552 Torsion angle 16-18 Tbs-L-phenylalanine chloromethyl ketone (TPCK) 278, 475 Transaldolase 79 Tyransducin-o 315-317 Transit time 123-125 Transition state 47-49 definition 55... 

TAS = 0) obtained with the 5 10°C temperature shift and the proportionally small optical changes in UV-Visible spectroscopy associated with the transient disequilibrium state. However, these limitations do not seem to apply to protein folding studies in which changes of tryptophan fluorescence or that of the fluorescently labeled proteins were monitored. In addition to a temperature jump, protein unfolding can also be rapidly initiated by a pressure jump. The dead time of the recently developed pressure-jump instrument is 50 ts for a pressure jump of 100 bar. ... 

Laser Temperature Jump for the Study of Early Events in Protein Folding... 

The laser temperature jump instrument can effectively be used to initiate and observe the fast events in protein/peptide folding and unfolding as well as those events that extend out to several milliseconds. In the present study, the unfolding of a helical peptide was determined to occur within tens of nanoseconds, supporting the need for nanosecond or faster initiation techniques. Promising results obtained by the laser temperature jump method will continue to stimulate the development of additional monitoring techniques such as UV absorption and circular dichroism. 

Hart T, Hosszu LLP, Trevitt CR et al (2009) Folding kinetics of the human prion protein probed by temperature jump. Proc Natl Acad Sci USA 106 5651-5656... 

Heat-shock proteins A group of Chapero-nins that accumulates in a cell after it has been subjected to a sudden temperature jump or other stress. They are thought to help deal with the accumulation of improperly folded or assembled proteins in stressed cells. 

Dimitriadis, G, Drysdafe, A, Myers, JK, Arora, P, Radford, SE, Oas, TG, et al, Microsecond folding dynamics of the F13W G29A mutant of the B domain of staphylococcal protein A by laser-induced temperature jump. Proceedings of the National Academy of Sciences of the United States of America 101 (2004) 3809-3814. 

Brewer, S.H., Song, B.B., Raleigh, D.P., Dyer, R.B. Residue specific resolution of protein folding dynamics using isotope-edited infrared temperature jump spectroscopy. Biochemistry 46, 3279-3285 (2007)... 

The first kinetic studies carried out by slow temperature jump experiments (Pohl, 1968a,b, 1969, 1972a,b, 1976), followed by kinetic analyses reported by Baldwin and co-workers (see Baldwin, 1975) originated the interpretation of the folding process in terms of sequential steps of reactions. It was proposed that the first one, nucleation, is dominated by entropy. Progressively, it was accepted that protein folding is a multistep process and the identification of intermediates became an important goal in the study of the formation of protein structure. 

---