@article {1356,
	title = {Collision-induced alignment of H2O+ drifting in helium},
	journal = {Journal of Chemical Physics},
	volume = {124},
	number = {17},
	year = {2006},
	note = {ISI Document Delivery No.: 039QQTimes Cited: 0Cited Reference Count: 27},
	month = {May},
	pages = {8},
	type = {Article},
	abstract = {The collision-induced alignment of H2O+ drifting in helium is studied with a molecular dynamics method that has been extended to treat nonlinear rigid ions. Rotational distribution functions and averaged quantities are presented in terms of the rho formalism [M. Thachuk, Phys. Rev. A 72, 032722 (2005)], and it is shown that this description gives a very good agreement with simulation results. In addition to velocity and angular velocity autocorrelation functions, a velocity-angular velocity cross correlation function is introduced. This cross correlation function provides insight into the dynamical nature of the alignment mechanism. 2006 American Institute of Physics.},
	keywords = {CROSS-SECTIONS, CYTOCHROME-C, ELECTROSTATIC FIELDS, IN-VACUO, INTRINSIC SIZE PARAMETERS, ION-MOTION, MOLECULAR-DYNAMICS, MONTE-CARLO-SIMULATION, POTENTIAL-ENERGY SURFACES, ROTATIONAL ALIGNMENT},
	isbn = {0021-9606},
	url = {<Go to ISI>://000237321700019},
	author = {Chen, X. and Thachuk, M.}
}
@article {1093,
	title = {Interaction of alamethicin with ether-linked phospholipid bilayers: Oriented circular dichroism, P-31 solid-state NMR, and differential scanning calorimetry studies},
	journal = {Biophysical Journal},
	volume = {89},
	number = {4},
	year = {2005},
	note = {ISI Document Delivery No.: 968FPTimes Cited: 22Cited Reference Count: 60},
	month = {Oct},
	pages = {2434-2442},
	type = {Article},
	abstract = {The arrangement of the antimicrobial peptide alamethicin was studied by oriented circular dichroism, 31 P solidstate NMR, and differential scanning calorimetry in ether- linked phospholipid bilayers composed of 1,2-O-dihexadecyl- sn-glycero3- phosphocholine ( DHPC). The measurements were performed as a function of alamethicin concentration relative to the lipid concentration, and results were compared to those reported in the literature for ester-linked phospholipid bilayers. At ambient temperature, alamethicin incorporates into the hydrophobic core of DHPC bilayers but results in more lipid disorder than observed for ester-linked 1-palmitoyl, 2-oleoyl-sn-glycero-3-phosphatidylcholine ( POPC) lipid bilayers. This orientational disorder appears to depend on lipid properties such as bilayer thickness. Moreover, the results suggest that alamethicin inserts into the hydrophobic core of the bilayers ( at high peptide concentration) for both ether- and ester-linked lipids but using a different mechanism, namely toroidal for DHPC and barrel-stave for POPC.},
	keywords = {BIOLOGICAL-MEMBRANES, CYTOCHROME-C, DIPHYTANOYL PHOSPHATIDYLCHOLINE, FUSION PEPTIDES, HYDROPHOBIC MISMATCH, LIPID-BILAYER, MOLECULAR-DYNAMICS SIMULATIONS, NUCLEAR-MAGNETIC-RESONANCE, THERMOTROPIC PHASE-BEHAVIOR, X-RAY-DIFFRACTION},
	isbn = {0006-3495},
	url = {<Go to ISI>://000232147600025},
	author = {Dave, P. C. and Billington, E. and Pan, Y. L. and Straus, S. K.}
}
@article {827,
	title = {Using ellipsoids to model charge distributions in gas phase protein complex ion dissociation},
	journal = {Canadian Journal of Chemistry-Revue Canadienne De Chimie},
	volume = {82},
	number = {12},
	year = {2004},
	note = {ISI Document Delivery No.: 898JHTimes Cited: 12Cited Reference Count: 31},
	month = {Dec},
	pages = {1736-1744},
	type = {Article},
	abstract = {Gas phase protein complex dissociation was modelled using ellipsoids on which discrete charges were placed in randomly chosen charge sites. A number of sizes, shapes, orientations, and types of ellipsoids were considered. For each case, charge transfer parameters and electrostatic energies were calculated as a function of the fractional surface area. It was found that to within 10-15\%, the charge on product ions after dissociation is distributed according to their fractional surface area. This can imply, for example, that in experiments measuring the dissociation of homodimers, charge asymmetries of greater than 10-15\% in the product ions signal that one of the ions has greatly increased its surface area, such as would occur with unfolding. This assumes that proton transfer occurs on a timescale fast enough that the dissociation products adopt the minimum electrostatic energy configuration. Calculation of this energy shows that it is minimized when one or more of the monomers is in an extended conformation.},
	keywords = {charge asymmetry, CYTOCHROME-C, ELECTROSPRAY-IONIZATION, ellipsoid charge model, EXCHANGE, IONIZATION MASS-SPECTROMETRY, ORIGIN, protein complex dissociation},
	isbn = {0008-4042},
	url = {<Go to ISI>://000227072600011},
	author = {Csiszar, S. and Thachuk, M.}
}
@article {681,
	title = {Conformations of gas-phase lysozyme ions produced from two different solution conformations},
	journal = {Analytical Chemistry},
	volume = {75},
	number = {6},
	year = {2003},
	note = {ISI Document Delivery No.: 657PQTimes Cited: 15Cited Reference Count: 41},
	month = {Mar},
	pages = {1325-1330},
	type = {Article},
	abstract = {Near pH 2.0, lysozyme in water is in its native conformation, and in water/methanol (2/8) it adopts a helical denatured conformation (Kamatari et al. Protein Sci. 1998, 7, 681-688). Hydrogen/deuterium (H/D) exchange of lysozyme in solution confirms that it is partially unfolded at pH 2.0 in water/methanol (v/v = 2/8). With electrospray ionization (ESI) mass spectrometry (MS), lysozyme in water produces ions with charges +7 to +12, with the greatest intensity at +10, whereas lysozyme in water/methanol (2/8) produces ions with charges +6 to +12 with the greatest intensity at +7. Thus, lysozyme is an exception to the rule that a protein denatured in solution forms higher charge states than the same protein in its folded native conformations in solution. Because the same charge states are produced from these two solution conformations, a direct comparison of the properties of the gas-phase ions produced from two very different solution conformations is possible. The conformations of lysozyme ions in the gas phase were studied using cross section measurements and gas-phase H/D exchange. Similar cross sections and H/D exchange levels were observed for same-charge states of lysozyme ions formed from the native and helical denatured conformations in solution. Cross sections show that the ions have compact structures. Thus, disulfide-intact gaseous lysozyme ions generated from the denatured state in water/methanol (2/8) refold into compact structures in the gas phase on a time scale of milliseconds or less.},
	keywords = {COLLISION, CROSS-SECTIONS, CYTOCHROME-C, EGG-WHITE LYSOZYME, H/D EXCHANGE, HYDROGEN-DEUTERIUM EXCHANGE, HYDROGEN/DEUTERIUM EXCHANGE, IONIZATION MASS-SPECTROMETRY, IONS, OF-FLIGHT SYSTEM, PROTEIN, UNFOLDING DYNAMICS},
	isbn = {0003-2700},
	url = {<Go to ISI>://000181675900014},
	author = {Mao, D. M. and Babu, K. R. and Chen, Y. L. and Douglas, D. J.}
}
@article {682,
	title = {H/D exchange of gas phase bradykinin ions in a linear quadrupole ion trap},
	journal = {Journal of the American Society for Mass Spectrometry},
	volume = {14},
	number = {2},
	year = {2003},
	note = {ISI Document Delivery No.: 643ZYTimes Cited: 14Cited Reference Count: 51},
	month = {Feb},
	pages = {85-94},
	type = {Article},
	abstract = {The gas phase H/D exchange reaction of bradykinin ions, as well as fragment ions of bradykinin generated through collisions in an orifice skimmer region, have been studied with a linear quadrupole ion trap (LIT) reflectron time-of-flight (rTOF) mass spectrometer system. The reaction in the trap takes only tens of seconds at a pressure of few mTorr of D2O or CD3OD. The exchange rate and hydrogen exchange level are not sensitive to the trapping q value over a broad range, provided q is not close to the stability boundary (q = 0.908). The relative rates and hydrogen exchange levels of protonated and sodiated +1 and +2 ions are similar to those observed previously by others with a Fourier transform ion cyclotron resonance (FTICR) mass spectrometer system. The doubly and triply protonated ions show multimodal isotopic distributions, suggesting the presence of several different conformations. The y fragment ions show greater exchange rates and levels than a or b ions, and when water or ammonia is lost from the fragment ions, no exchange is observed. (J Am Soc Mass Spectrom 2003, 14, 85-94) (C) 2003 American Society for Mass Spectrometry.},
	keywords = {ACTIVATED DISSOCIATION, COLLISIONAL ACTIVATION, CYTOCHROME-C, HYDROGEN-DEUTERIUM EXCHANGE, HYDROGEN/DEUTERIUM EXCHANGE, INFRARED, IONIZATION MASS-SPECTROMETRY, OF-FLIGHT SYSTEM, PEPTIDE IONS, PROTEIN IONS, RADIATIVE DISSOCIATION},
	isbn = {1044-0305},
	url = {<Go to ISI>://000180894500001},
	author = {Mao, D. M. and Douglas, D. J.}
}
@article {439,
	title = {Hydrogen/deuterium exchange of myoglobin ions in a linear quadrupole ion trap},
	journal = {Rapid Communications in Mass Spectrometry},
	volume = {16},
	number = {20},
	year = {2002},
	note = {ISI Document Delivery No.: 604ADTimes Cited: 10Cited Reference Count: 26},
	pages = {1941-1945},
	type = {Article},
	abstract = {The hydrogen/deuterium (H/D) exchange of gas-phase ions of holo- and apo-myoglobin has been studied by confining the ions in a linear quadrupole ion trap with D2O or CD3OD at a pressure of several mTorr. Apo-myoglobin ions were formed by collision-induced dissociation of holomyoglobin ions between the orifice and skimmer of the ion sampling system. The exchange takes place on a time scale of seconds. Earlier cross section measurements have shown that holomyoglobin ions can have more compact structures than apo-myoglobin. Despite this, both holomyoglobin and apo-myoglobin in charge states +8 to +14 are found to exchange nearly the same number of hydrogens (ca. 103) in 4 s. It is possible the ions fold or unfold to new conformations on the much longer time scale of the exchange experiment compared with the cross section measurements. Copyright (C) 2002 John Wiley Sons, Ltd.},
	keywords = {COLLISION CROSS-SECTIONS, CYTOCHROME-C, GAS-PHASE, HEME, HOLOMYOGLOBIN, HYDROGEN-DEUTERIUM EXCHANGE, MASS-SPECTROMETRY, OF-FLIGHT, PROTEIN IONS, STABILITY, SYSTEM},
	isbn = {0951-4198},
	url = {<Go to ISI>://000178592700007},
	author = {Mao, D. M. and Ding, C. F. and Douglas, D. J.}
}
@article {5189,
	title = {Collision-induced dissociation of bradykinin ions in the interface region of an ESI-MS},
	journal = {Journal of the American Society for Mass Spectrometry},
	volume = {12},
	number = {7},
	year = {2001},
	note = {ISI Document Delivery No.: 447HHTimes Cited: 17Cited Reference Count: 42},
	month = {Jul},
	pages = {772-779},
	type = {Article},
	abstract = {By applying different electric field strengths to the orifice-skimmer region of an electrospray ionization mass spectrometer, the rate of dissociation can be varied based on the amount of infernal energy acquired by an ion through collisions: with the curtain gas molecules. Both the Arrhenius equation and Rice-Ramsperger-Kassel (RRK) theory can be used to predict the rate of dissociation of internally excited molecules. A previously determined model for collision-induced dissociation is tested by comparison of predicted and experimentally observed orifice-skimmer potential differences for dissociation of ions. The rate of collision-induced dissociation of bradykinin ions is determined by monitoring the fragments produced in a mass spectrometer. The semi-quantitative model is found to yield effective predictions when accurate Arrhenius and RRK parameters are utilized. (C) 2001 American Society for Mass Spectrometry.},
	keywords = {ACTIVATION, CYTOCHROME-C, ELECTROSPRAY-IONIZATION, GAS-PHASE, IDENTIFICATION, INFRARED RADIATIVE DISSOCIATION, IONIZATION MASS-SPECTROMETRY, MOLECULES, PEPTIDES, PROTEIN IONS},
	isbn = {1044-0305},
	url = {<Go to ISI>://000169565500002},
	author = {Schneider, B. B. and Douglas, D. J. and Chen, D. D. Y.}
}
@article {5053,
	title = {Detection of noncovalent complex between alpha-amylase and its microbial inhibitor tendamistat by electrospray ionization mass spectrometry},
	journal = {Rapid Communications in Mass Spectrometry},
	volume = {15},
	number = {2},
	year = {2001},
	note = {ISI Document Delivery No.: 396KYTimes Cited: 11Cited Reference Count: 58},
	pages = {89-96},
	type = {Article},
	abstract = {Electrospray ionization mass spectrometry (ESI-MS) is now routinely used for detection of noncovalent complexes. However, detection of noncovalent protein-protein complexes is not a widespread practice and still produces some challenges for mass spectrometrists. Here we demonstrate the detection of a noncovalent protein-protein complex between alpha -amylase and its microbial inhibitor tendamistat using ESI-MS. Crude porcine pancreatic alpha -amylase was purified using a glycogen precipitation method. Noncovalent complexes between porcine pancreatic alpha -amylase and its microbial inhibitor tendamistat are probed and detected using ESI-MS. The atmosphere-vacuum ESI conditions along with solution conditions and the ratio of inhibitor over enzyme strongly affect the detection of noncovalent complexes in the gas phase. ESI mass spectra of alpha -amylase at pH 7 exhibited charge states significantly lower than that reported previously, which is indicative of a native protein conformation necessary to produce a noncovalent complex. Detection of noncovalent complexes in the gas phase suggests that further use of conventional biochemical approaches to provide a qualitative, and in some cases even quantitative, characterization of equilibria of noncovalent complexes in solution is possible. Copyright (C) 2001 John Wiley \& Sons, Ltd.},
	keywords = {ANALYTICAL ULTRACENTRIFUGATION, BINDING, CRYSTAL-STRUCTURE, CYTOCHROME-C, GAS-PHASE, HEME, MYOGLOBIN, PROBING CONFORMATIONAL-CHANGES, PROTEIN PROTEINASE-INHIBITORS, RECOGNITION SITES},
	isbn = {0951-4198},
	url = {<Go to ISI>://000166636600003},
	author = {Douglas, D. J. and Collings, B. A. and Numao, S. and Nesatyy, V. J.}
}
@article {4924,
	title = {Collision-induced dissociation of ions within the orifice-skimmer region of an electrospray mass spectrometer},
	journal = {Analytical Chemistry},
	volume = {72},
	number = {4},
	year = {2000},
	note = {ISI Document Delivery No.: 285HETimes Cited: 38Cited Reference Count: 33},
	month = {Feb},
	pages = {791-799},
	type = {Article},
	abstract = {An equation was derived to describe the variation of the gas number density within the region between the orifice and the skimmer of an electrospray ionization mass spectrometer. The equation was used to develop a semiquantitative model to predict the value of orifice voltages that lead to ion fragmentation within this region. This model made it possible to predict the types of solvent adducts observed for analytes at various orifice voltages. In addition, it is shown that a small number of high-energy collisions is equally effective for collision-induced dissociation as compared to a large number of low-energy collisions. Finally, this model is tested with different background electrolyte solutions and a different electrospray mass spectrometer. It is demonstrated that controlled fragmentation studies can be performed on single-quadrupole mass spectrometers, and the proposed model gives a reasonable description of the fragmentation process in both spectrometers.},
	keywords = {capillary electrophoresis, CYTOCHROME-C, DYNAMICS, IDENTIFICATION, INTERFACE, IONIZATION, LIQUID-CHROMATOGRAPHY, PROTEINS, SENSITIVITY, SEPARATION},
	isbn = {0003-2700},
	url = {<Go to ISI>://000085383000019},
	author = {Schneider, B. B. and Chen, D. D. Y.}
}
@article {4726,
	title = {Methanol-induced conformations of myoglobin at pH 4.0},
	journal = {Biochemistry},
	volume = {39},
	number = {47},
	year = {2000},
	note = {ISI Document Delivery No.: 378UETimes Cited: 62Cited Reference Count: 78},
	month = {Nov},
	pages = {14702-14710},
	type = {Article},
	abstract = {The equilibrium methanol-induced conformation changes of holomyoglobin (hMb) at pH 4.0 have been studied by circular dichroism, tryptophan fluorescence, and Soret band absorption and by electrospray ionization mass spectrometry (ESI-MS). Optical spectra show the following: (1) In 35-40\% (v/v) methanol/water, the native-like secondary structure remains, the tertiary structure is lost, the heme protein interactions are decreased, and a folding intermediate is formed. (2) In 50\% methanol, heme is lost from the protein, and there is a small decrease in helicity together with a loss of tertiary structure. (3) At > 60\% methanol, the helicity increases and the apoprotein goes into a helical denatured state. The conformations are also probed by the charge states produced in ESI-MS and by hydrogen/deuterium (H/D) exchange with mass measurement by ESI-MS. At 0-30\% methanol, native hMb produces relatively low charge states (9(+)-13(+)) in ESI-MS and exchanges relatively few hydrogens. In 35-40\% methanol, at which an intermediate is formed, there is a bimodal distribution of hMb ions with both low (9(+)-13(+)) and high (14(+)-23(+)) charge states and also a high charge state distribution (12(+)-26(+)) of apomyoglobin (aMb) ions. Low and high charge states of hMb and a high charge state of aMb all show the same H/D exchange rate, indicating that an unfolded hMb intermediate interconverts between folded hMb and unfolded aMb. The charge state distribution for the unfolded hMb intermediate observed here is similar to that of the recently reported transient intermediate formed during the acid denaturation of hMb. At 50\% alcohol the protein produces predominantly high charge states of aMb ions and shows H/D exchange rates close to those of the acid-denatured protein. H/D exchange of the helical denatured protein at alcohol concentrations >60\%, at which high charge states of aMb are produced, shows that the protein structure is more protected than at similar to 50\% methanol.},
	keywords = {AMIDE HYDROGEN-EXCHANGE, APOMYOGLOBIN, BETA-LACTOGLOBULIN, CYTOCHROME-C, ELECTROSPRAY-IONIZATION, FOLDING INTERMEDIATE, IONIZATION MASS-SPECTROMETRY, MOLTEN GLOBULE INTERMEDIATE, SPERM-WHALE, STRUCTURAL-CHARACTERIZATION, X-RAY-SCATTERING},
	isbn = {0006-2960},
	url = {<Go to ISI>://000165602400040},
	author = {Babu, K. R. and Douglas, D. J.}
}
@article {4314,
	title = {Equilibrium unfolding of proteins monitored by electrospray ionization mass spectrometry: Distinguishing two-state from multi-state transitions},
	journal = {Rapid Communications in Mass Spectrometry},
	volume = {12},
	number = {8},
	year = {1998},
	note = {ISI Document Delivery No.: ZJ143Times Cited: 79Cited Reference Count: 59},
	pages = {435-442},
	type = {Article},
	abstract = {The acetic acid-induced unfolding of cytochrome c (cyt c) and apomyoglobin (aMb) are studied under equilibrium conditions by electrospray ionization (ESI) mass spectrometry (MS), The folding states of the proteins in solution are monitored by the charge state distributions that they produce during ESI, A tightly folded protein shows lower charge states than the same protein in an unfolded conformation. The ESI-MS data presented in this study show that during the denaturation of cyt c, only two distinct charge state distributions are observed. These can be attributed to the native and to the acid-unfolded conformation, respectively. In the transition region where the folded and the unfolded conformation are both present in solution, these two distributions are observed simultaneously, thus giving rise to a bimodal ESI mass spectrum. These data reflect a highly cooperative (two state) folding behavior. In contrast, the acid-induced unfolding of aMb is accompanied by gradual shifts in the maxima of the observed charge state distribution. This indicates a non cooperative unfolding behavior involving multiple protein conformations. The observations made here suggest that ESI-MS might be a general method for assessing the cooperativity of protein unfolding transitions. This study also addresses the issue of {\textquoteright}secondary{\textquoteright} solvent effects for ESI-MS studies on the acid-induced unfolding of proteins. These effects influence the ESI charge state distribution without being related to conformational changes of the protein in solution and could potentially complicate the interpretation of ESI mass spectra, Data obtained for bovine pancreatic trypsin inhibitor and ubiquitin indicate that secondary solvent effects influence the observed charge state distributions only to a very minor extent between pH 8.5 and 2.5. (C) 1998 John Wiley \& Sons, Ltd.},
	keywords = {CONFORMATIONAL-CHANGES, CYTOCHROME-C, FERRICYTOCHROME-C, FOLDING, HYDROGEN-DEUTERIUM EXCHANGE, INTERMEDIATE, MOLECULAR-BASIS, MOLTEN GLOBULE, NMR-SPECTROSCOPY, POSITIVE-ION, STRUCTURAL CHARACTERIZATION},
	isbn = {0951-4198},
	url = {<Go to ISI>://000073183800005},
	author = {Konermann, L. and Douglas, D. J.}
}
@article {4447,
	title = {Pre-steady state kinetic analysis of an enzymatic reaction monitored by time-resolved electrospray ionization mass spectrometry},
	journal = {Biochemistry},
	volume = {37},
	number = {21},
	year = {1998},
	note = {ISI Document Delivery No.: ZR717Times Cited: 73Cited Reference Count: 53},
	month = {May},
	pages = {7664-7669},
	type = {Article},
	abstract = {For the first time, the new technique of time-resolved electrospray ionization mass spectrometry (ESI-MS) has been used to accurately measure the pre-steady state kinetics of an enzymatic reaction by monitoring a transient enzyme intermediate. The enzyme used to illustrate this approach, Bacillus circulans xylanase, is a retaining glycosidase that hydrolyzes xylan or beta-xylobiosides through a double-displacement mechanism involving a covalent xylobiosyl-enzyme intermediate. A low steady state level of this intermediate formed during the hydrolysis of 2,5-dinitrophenyl beta-D-xylobioside was detected by time-resolved ESI-MS. The low concentration of this intermediate and its rate of formation did not permit pre-steady state kinetic analysis. By contrast, the covalent intermediate accumulates fully when the Tyr80Phe mutant hydrolyzes the same substrate. Using time-resolved ESI-MS, the pre-steady state kinetic parameters for the formation of the covalent intermediate in the mutant xylanase have been determined. The kinetic data are in agreement with those determined by monitoring the release of 2,5-dinitrophenol with stopped-flow W-vis spectroscopy. This demonstrates that time-resolved ESI-MS can be used to accurately monitor the pre-steady state kinetics of enzymatic reactions, with the advantage of identifying transient enzyme intermediates by their mass.},
	keywords = {ACTIVE-SITE NUCLEOPHILE, AMINO-ACID, BACILLUS-CIRCULANS XYLANASE, beta-glucosidase, CELLULASES, CYTOCHROME-C, GAS-PHASE, IDENTIFICATION, inhibitors, MECHANISMS},
	isbn = {0006-2960},
	url = {<Go to ISI>://000074006700002},
	author = {Zechel, D. L. and Konermann, L. and Withers, S. G. and Douglas, D. J.}
}
@article {4227,
	title = {Stability of a highly charged noncovalent complex in the gas phase: Holomyoglobin},
	journal = {Rapid Communications in Mass Spectrometry},
	volume = {12},
	number = {15},
	year = {1998},
	note = {ISI Document Delivery No.: 105GATimes Cited: 33Cited Reference Count: 56},
	pages = {1003-1010},
	type = {Article},
	abstract = {Gas phase holomyoglobin (hMb) ions in charge states +7 to +21 were formed by electrospray ionization in combination with a continuous-flow mixing apparatus. Collision cross section measurements show that the highly charged ions are somewhat unfolded in comparison to low charge states but still retain a considerable degree of folding. A new collision model is presented which calculates the relative energies transferred to complexes in tandem mass spectrometry. Tandem mass spectrometry and ion trapping experiments both show that the energies required to dissociate heme from the highly charged heme-protein complexes in the gas phase are similar to those of low charge states, previously shown in literature ion cyclotron resonance experiments to be 0.7-1.0 eV, These energies are comparable to those of the heme binding energy in solution. The results suggest that even for the highly charged hMb ions which have unfolded somewhat, the heme-protein interactions remain relatively unperturbed. (C) 1998 John Wiley \& Sons, Ltd.},
	keywords = {CONFORMATION, CYTOCHROME-C, ELECTROSPRAY-IONIZATION, ion-molecule, IONIZATION MASS-SPECTROMETRY, METMYOGLOBIN, MYOGLOBIN, PROTEIN IONS, PROTON-TRANSFER REACTIVITY, QUADRUPOLE, reaction},
	isbn = {0951-4198},
	url = {<Go to ISI>://000075063300003},
	author = {Chen, Y. L. and Campbell, J. M. and Collings, B. A. and Konermann, L. and Douglas, D. J.}
}
@article {4313,
	title = {Unfolding of proteins monitored by electrospray ionization mass spectrometry: A comparison of positive and negative ion modes},
	journal = {Journal of the American Society for Mass Spectrometry},
	volume = {9},
	number = {12},
	year = {1998},
	note = {ISI Document Delivery No.: 141FPTimes Cited: 72Cited Reference Count: 56},
	month = {Dec},
	pages = {1248-1254},
	type = {Article},
	abstract = {Electrospray ionization (ESI) mass spectrometry (MS) in both the positive and negative ion mode has been used to study protein unfolding transitions of lysozyme, cytochrome c (cyt c), and ubiquitin in solution. As expected, ESI of unfolded lysozyme leads to the formation of substantially higher charge states than the tightly folded protein in both modes of operation. Surprisingly, the acid-induced unfolding of cyt c as well as the acid and the base-induced unfolding of ubiquitin show different behavior: In these three cases protein unfolding only leads to marginal changes in the negative ion charge state distributions, whereas in the positive ion mode pronounced shifts to higher charge states are observed. This shows that ESI MS in the negative ion mode as a method for probing conformational changes of proteins in solution should be treated with caution. The data presented in this work provide further evidence that the conformation of a protein in solution not its charge state is the predominant factor for determining the ESI charge slate distribution in the positive ion mode. Furthermore, these data support the hypothesis of a recent study (Konermann and Douglas, Biochemistry 1997, 36, 12296-12302) which suggested that ESI in the positive ion mode is not sensitive to changes in the secondary structure of proteins but only to changes in the tertiary structure. (C) 1998 American Society for Mass Spectrometry.},
	keywords = {A-STATE, BINDING, CIRCULAR-DICHROISM, CYTOCHROME-C, HYDROGEN-DEUTERIUM EXCHANGE, INDUCED CONFORMATIONAL-CHANGES, MYOGLOBIN, NUCLEAR-MAGNETIC-RESONANCE, SITES, SPECTRA, UBIQUITIN},
	isbn = {1044-0305},
	url = {<Go to ISI>://000077132600002},
	author = {Konermann, L. and Douglas, D. J.}
}
@article {3635,
	title = {Conformation of gas-phase myoglobin ions},
	journal = {Journal of the American Chemical Society},
	volume = {118},
	number = {18},
	year = {1996},
	note = {ISI Document Delivery No.: UK145Times Cited: 89Cited Reference Count: 33},
	month = {May},
	pages = {4488-4489},
	type = {Article},
	keywords = {CYTOCHROME-C, ELECTROSPRAY MASS-SPECTROMETRY, IONIZATION, PROTEINS},
	isbn = {0002-7863},
	url = {<Go to ISI>://A1996UK14500034},
	author = {Collings, B. A. and Douglas, D. J.}
}
