@article {332,
	title = {A differential vapor-pressure equipment for investigations of biopolymer interactions},
	journal = {Journal of Biochemical and Biophysical Methods},
	volume = {50},
	number = {2-3},
	year = {2002},
	note = {ISI Document Delivery No.: 510CETimes Cited: 7Cited Reference Count: 47},
	month = {Jan},
	pages = {269-288},
	type = {Article},
	abstract = {The design and performance of an equipment for the measurement of vapor pressures over liquid or solid samples is presented. The equilibrium pressure difference, DeltaP, between a sample and a reference of known vapor pressure is recorded as a function of composition and/or temperature. Through the use of high-accuracy capacitance manometers and a leak-tight system of stainless steel pipes, below-scaled valves and metal-gasket fittings, DeltaP can be measured with a resolution of about 0.5 mubar (0.05 Pa) in some applications. This sensitivity level, along with other features of the equipment, particularly a "gas-phase titration" routine for changing the cell composition, makes it effective for the investigations of several types of biopolymer interactions. These include isothermal studies of net affinities such as the adsorption of water to proteins or membranes, the preferential interaction of biopolymers with the components of a mixed solvent. the partitioning of solutes between a membrane and the aqueous bulk and the weak. specific binding of ligands to macromolecules. Furthermore, a temperature-scanning mode allows real-time elucidation of such interactions at thermally induced conformational changes in biopolymers. Selected examples of these applications are presented and discussed. (C) 2002 Elsevier Science B.V. All rights reserved.},
	keywords = {25-DEGREES-C, ALCOHOLS, BINDING, BOVINE SERUM-ALBUMIN, CALORIMETER, differential, hydration, LIQUID-EQUILIBRIA, preferential interaction, static vapor pressure, temperature scanning, TEMPERATURES, THERMODYNAMICS, titration, WATER, weak binding},
	isbn = {0165-022X},
	url = {<Go to ISI>://000173190500016},
	author = {Andersen, K. B. and Koga,Yoshikata and Westh, P.}
}
@article {4020,
	title = {Complete measurement of the pK(a) values of the carboxyl and imidazole groups in Bacillus circulans xylanase},
	journal = {Protein Science},
	volume = {6},
	number = {12},
	year = {1997},
	note = {ISI Document Delivery No.: YK912Times Cited: 44Cited Reference Count: 29},
	month = {Dec},
	pages = {2667-2670},
	type = {Article},
	abstract = {Electrostatic interactions in proteins can be dissected experimentally by determining the pK(a), values of their constituent ionizable amino acids. To complement previous studies of the glutamic acid and histidine residues in Bacillus circulans xylanase (BCX), we have used NMR methods to measure the pK(a)s of the seven aspartic acids and the C-terminus of this protein. The pK(a)s of these carboxyls are all less than the corresponding values observed with random coil polypeptides, indicating that their ionization contributes favorably to the stability of the folded enzyme. In general, the aspartic acids with the most reduced pK(a)s are those with limited exposure to the solvent and a high degree of conservation among homologous xylanases. Most dramatically, Asp 53 and Asp 101 have pK(a)s < 2 and thus remain deprotonated in native BCX under all conditions examined. Asp 83 is completely buried, forming a strong salt bridge with Arg 136. In contrast, Asp 101 is located on the surface of the protein, stabilized in the deprotonated form by an extensive network of hydrogen bonds involving an internal water molecule and the neutral side-chain and main-chain atoms of Ser 100 and Thr 145. These data provide a complete experimental database for theoretical studies of the ionization behavior of BCX under acidic conditions.},
	keywords = {aspartic acid, electrostatics, FAMILIES, NMR, NMR ASSIGNMENTS, NUCLEAR-MAGNETIC-RESONANCE, PK(A), PROTEINS, RESIDUES, SHIFTS, titration, XYLANASE},
	isbn = {0961-8368},
	url = {<Go to ISI>://A1997YK91200024},
	author = {Joshi, M. D. and Hedberg, A. and McIntosh, L. P.}
}
