@article{BuscagliaSchulerLapidusetal.2003,
  author    = {Buscaglia, Marco and Schuler, Benjamin and Lapidus, Lisa J. and Eaton, Wiliam A. and Hofrichter, James},
  title     = {Kinetics of intramolecular contact formation in a denatured protein},
  issn      = {0022-2836},
  year      = {2003},
  abstract  = {Quenching of the triplet state of tryptophan by cysteine has provided a new tool for measuring the rate of forming a specific intramolecular contact in disordered polypeptides. Here, we use this technique to investigate contact formation in the denatured state of CspTm, a small cold-shock protein from Thermotoga maritima, engineered to contain a single tryptophan residue (W29) and a single cysteine residue at the C terminus (C67). At all concentrations of denaturant, the decay rate of the W29 triplet of the unfolded protein is more than tenfold faster than the rate observed for the native protein (not, vert, similar104 s;1). Experiments on the unfolded protein without the added C- terminal cysteine residue show that this faster rate results entirely from contact quenching by C67. The quenching rate in the unfolded state by C67 increases at concentrations of denaturant that favor folding, indicating a compaction of the unfolded protein as observed previously in single-molecule Foerster resonance energy transfer (FRET) experiments.},
  language  = {en}
}
@article{TolanSchulerBeerninketal.2003,
  author    = {Tolan, Dean R. and Schuler, Benjamin and Beernink, Peter T. and Jaenicke, Rainer},
  title     = {Thermodynamic analysis of the dissociation of the aldolase tetramer substituted at one or both of the subunit interfaces},
  year      = {2003},
  abstract  = {The fructose-1,6-bis(phosphate) aldolase isologous tetramer tightly associates through two different subunit interfaces defined by its 222 symmetry. Both single- and double-interfacial mutant aldolases have a destabilized quaternary structure, but there is little effect on the catalytic activity. These enzymes are however thermolabile. This study demonstrates the temperature-dependent dissociation of the mutant enzymes and determines the dissociation free energies of both mutant and native aldolase. Subunit dissociation is measured by sedimentation equilibrium in the analytical ultracentrifuge. At 25C the tetramerdimer dissociation constants for each single-mutant enzyme are similar, about 10 -6 M. For the double-mutant enzyme, sedimentation velocity experiments on sucrose density gradients support a tetramermonomer equilibrium. Furthermore, sedimentation equilibrium experiments determined a dissociation constant of 10- 15 M3 for the double-mutant enzyme. By the same methods the upper limit for the dissociation constant of wild-type aldolase A is approximately 10-28 M3, which indicates an extremely stable tetramer. The thermodynamic values describing monomer-tetramer and dimer-tetramer equilibria are analyzed with regard to possible cooperative interaction between the two subunit interfaces.},
  language  = {en}
}
@article{LipmanSchulerBakajinetal.2003,
  author    = {Lipman, Everett A. and Schuler, Benjamin and Bakajin, Olgica and Eaton, William A.},
  title     = {Single-molecule measurement of protein folding kinetics},
  issn      = {0036-8075},
  year      = {2003},
  abstract  = {In order to investigate the behavior of single molecules under conditions far from equilibrium, we have coupled a microfabricated laminar-flow mixer to a confocal optical system. This combination enables time-resolved measurement of Foerster resonance energy transfer after an abrupt change in solution conditions. Observations of a small protein show the evolution of the intramolecular distance distribution as folding progresses. This technique can expose subpopulations, such as unfolded protein under conditions favoring the native structure, that would be obscured in equilibrium experiments.},
  language  = {en}
}