@article {4028,
	title = {Cytochrome c folding kinetics studied by time-resolved electrospray ionization mass spectrometry},
	journal = {Biochemistry},
	volume = {36},
	number = {18},
	year = {1997},
	note = {ISI Document Delivery No.: WY063Times Cited: 82Cited Reference Count: 46},
	month = {May},
	pages = {5554-5559},
	type = {Article},
	abstract = {A new method for studying the folding kinetics of proteins is described. The method combines a continuous flow mixing technique with an electrospray mass spectrometer. Different protein conformations in solution are detected by the different charge states they produce during electrospray ionization. Unfolded proteins generally have more accessible protonation sites and give higher charge states than native proteins. The method is applied to study the refolding of acid-denatured cytochrome c. Global data analysis is used to obtain the exponential lifetimes which are associated with the refolding process. The kinetics can be described by two lifetimes of 0.17 +/- 0.02 and 8.1 +/- 0.9 s which are in accordance with the results of stopped flow experiments previously described in the literature. These lifetimes are associated with roughly 90 and 10\% of the total intensity changes in the mass spectrum, respectively, and most likely reflect fast and slow refolding subpopulations of cytochrome c in solution.},
	keywords = {COMPLEX, denaturation, FERRICYTOCHROME-C, IRON BLEOMYCIN, LIGANDS, MECHANISM, PATHWAYS, PROBING CONFORMATIONAL-CHANGES, PROTEINS, SPECTRA},
	isbn = {0006-2960},
	url = {<Go to ISI>://A1997WY06300029},
	author = {Konermann, L. and Collings, B. A. and Douglas, D. J.}
}
@article {3848,
	title = {Intermolecular interactions in 2-butoxyethanol-DMSO-H2O},
	journal = {Journal of Physical Chemistry},
	volume = {100},
	number = {1},
	year = {1996},
	note = {ISI Document Delivery No.: TN839Times Cited: 15Cited Reference Count: 23},
	month = {Jan},
	pages = {433-438},
	type = {Article},
	abstract = {Excess partial molar enthalpy, H-B(E), and chemical potential, mu(B)(E), of 2-butoxyethanol (B) were determined in ternary mixtures of B, dimethyl sulfoxide (D), and H2O. The data were obtained in small enough mole fraction increments to evaluate the so-called interaction functions, partial derivative H-B(E)/partial derivative x(B), partial derivative H-B(E)/partial derivative x(D), partial derivative mu(B)(E)/partial derivative x(B), and partial derivative mu(B)E/partial derivative x(D). These interaction functions previously proved useful in elucidating the {\textquoteright}{\textquoteright}mixing schemes{\textquoteright}{\textquoteright} in binary aqueous solutions of B and D. For the binary mixtures, it was found that both B and D influenced H2O in the following manner: in the water-rich composition range (region I) within a certain threshold (x(B) < 0.0175 and x(D) < 0.28 at 25 degrees C), both solutes enhance the hydrogen-bonded network of water in their vicinity, and the mixtures retain the percolated nature of the network. At higher B or D concentrations (region II) a qualitatively different mixing scheme becomes operative. The results from this work suggest that, in the ternary mixtures, solute B and D influences the percolated hydrogen bond network of water competitively or cooperatively. The observed effects are in accordance with those characteristic of mixing scheme I in the binary mixtures, as long as the concentration of both solutes is within the threshold values. When either one of the solutes is concentrated beyond its threshold, mixing scheme II seems to set in. It was found that D diminished the positive (unfavorable) enthalpy of B-B interactions and that this effect was almost completely compensated by changes in interaction entropy. Hence, D had little net effect on the Gibbs energy of mutual B interactions, or in other words, D did not weaken the hydrophobic attraction between B molecules. Evaluation of {\textquoteright}{\textquoteright}heterogeneous{\textquoteright}{\textquoteright} B-D interactions in region I suggested that they were weaker than B-B interactions and governed by reorganization of water-water hydrogen bonding rather than interactions between specific groups in B and D. Some implications of these findings on cosolvent effects in aqueous solutions of biopolymers are discussed.},
	keywords = {AQUEOUS 2-BUTOXYETHANOL, denaturation, DIMETHYL-SULFOXIDE, LYSOZYME, MIXING SCHEME, MIXTURES, NEUTRON-DIFFRACTION, PARTIAL MOLAR ENTHALPIES, VOLUMES, WATER-RICH REGION},
	isbn = {0022-3654},
	url = {<Go to ISI>://A1996TN83900065},
	author = {Westh, P. and Koga,Yoshikata}
}
@article {3720,
	title = {Multiple pathways for denaturation of horse plasma gelsolin},
	journal = {Biochemistry and Cell Biology-Biochimie Et Biologie Cellulaire},
	volume = {74},
	number = {1},
	year = {1996},
	note = {ISI Document Delivery No.: UE605Times Cited: 1Cited Reference Count: 38},
	pages = {101-107},
	type = {Article},
	abstract = {Gelsolin purified from horse plasma carries a surface charge distribution that greatly influences how the protein unfolds, aggregates, or precipitates as a function of temperature or concentration of chemical denaturant. Modification of gelsolin with fluorescein isothiocyanate replaces positive charges on amine groups with bulky, negatively charged fluorescein moieties. This postpones thermally induced precipitation by about 10 degrees C [Koepf, E.K., and Burtnick, L.D. 1993. Eur. J. Biochem. 212: 713-718]. Interaction with cations such as Ca2+ or guanidinium(+) also alters the surface charge on gelsolin. This affects the structure of the protein in solution, modifies the pathway for unfolding, and moderates the onset of precipitation induced by chemical denaturants or heat. Denaturation of gelsolin is not interpretable in terms of a simple two-state cooperative mechanism. The pathway to a denatured state and intermediate structures present along the way depend upon the agent used to unfold the protein.},
	keywords = {ACTIN-BINDING-SITES, calcium, chemical, circular dichroism, denaturation, FLUORESCEIN ISOTHIOCYANATE, gelsolin, PROTEIN, thermal},
	isbn = {0829-8211},
	url = {<Go to ISI>://A1996UE60500011},
	author = {Koepf, E. K. and Burtnick, L. D.}
}
@article {7358,
	title = {MONOMER AND EXCIMER FLUORESCENCE OF HORSE PLASMA GELSOLIN LABELED WITH N-(1-PYRENYL)IODOACETAMIDE},
	journal = {Biochemistry and Cell Biology-Biochimie Et Biologie Cellulaire},
	volume = {70},
	number = {7},
	year = {1992},
	note = {ISI Document Delivery No.: JP667Times Cited: 3Cited Reference Count: 27},
	month = {Jul},
	pages = {573-578},
	type = {Article},
	abstract = {Horse plasma gelsolin was labelled with the sulfhydryl-specific fluorescent reagent N-(1-pyrenyl)iodoacetamide. The level of incorporation of probe was 1.6 +/- 0.3 mol pyrene/mol gelsolin. The circular dichroism spectrum of pyrenyl-gelsolin and its ability to interact with muscle actin were not different from that found for unmodified gelsolin. The emission from pyrenyl-gelsolin was dominated by a broad emission band centred near 483 nm, characteristic of the presence of pyrene excimers. Analysis of excitation spectra for the monomer and excimer-type fluorescence suggested that ground-state interactions may occur between adjacent pyrenes in the gelsolin structure. In the case either of excimer formation or of ground-state pyrene-pyrene interactions in doubly labelled gelsolin molecules, the modified Cys residues must be in close proximity in the folded protein structure. Thermal denaturation of gelsolin could be monitored by observing the decrease in excimer emission that accompanied heating and unfolding of the tertiary structure. While heat treatment alone did not eliminate excimer fluorescence, digestion of gelsolin with chymotrypsin completely abolished such emission. Also, pyrenyl-gelsolin prepared and studied in 6 M guanidine-HCl exhibited fluorescence characteristic of pyrene monomers exclusively.},
	keywords = {ACTIN-FILAMENTS, BINDING, CIRCULAR-DICHROISM, denaturation, FLUORESCENCE LIFETIME, gelsolin, POLYMERIZATION, PROBE, PROTEIN, PYRENE EXCIMER FLUORESCENCE, PYRENE-ACTIN, STATE, thermal, TROPOMYOSIN},
	isbn = {0829-8211},
	url = {<Go to ISI>://A1992JP66700008},
	author = {Silva, B. E. R. and Koepf, E. K. and Burtnick, L. D. and Turro, N. J.}
}
@article {7352,
	title = {STABILIZATION OF THE STRUCTURE OF HORSE PLASMA VITAMIN-D BINDING-PROTEIN BY DISULFIDE BONDS},
	journal = {Biochemistry and Cell Biology-Biochimie Et Biologie Cellulaire},
	volume = {70},
	number = {1},
	year = {1992},
	note = {ISI Document Delivery No.: HG742Times Cited: 1Cited Reference Count: 27},
	month = {Jan},
	pages = {10-15},
	type = {Article},
	abstract = {Vitamin D binding protein (DBP) was isolated from horse plasma in a four-step procedure that involved Affi-Gel Blue affinity chromatography, gel filtration, hydroxylapatite chromatography, and anion exchange high-pressure liquid chromatography. The yield of DBP from 80 mL of plasma was 6-7 mg. Horse plasma DBP closely resembles other plasma DBPs, being a tryptophan-free protein of M(r) 53 000. It is able to bind to and block the polymerization of monomeric actin. The secondary structure of DBP was calculated from circular dichroism measurements to be 39\% alpha-helix, 42\% beta-sheet, and 19\% random coil. Circular dichroism and fluorescence studies revealed that the disulfide bonds of DBP contribute substantial structural stabilization to the molecule with respect to thermal denaturation. The thermal stability of DBP can be used to advantage. Incorporation of a brief treatment at 70-degrees-C into the preparative scheme enables omission of one chromatographic step, without detectable alteration of the purified product.},
	keywords = {actin, circular dichroism, CIRCULAR-DICHROISM, COMPLEX, denaturation, DISULFIDE BONDS, FLUORESCENCE, GC-GLOBULIN, POLYMERIZATION, RAT, SERUM, thermal, TROPOMYOSIN, VITAMIN-D BINDING PROTEIN},
	isbn = {0829-8211},
	url = {<Go to ISI>://A1992HG74200002},
	author = {Robinson, R. C. and Burtnick, L. D.}
}
