@article {2309,
	title = {Conformations of Gas-Phase Ions of Ubiquitin, Cytochrome c, Apomyoglobin, and beta-Lactoglobulin Produced from Two Different Solution Conformations},
	journal = {Journal of the American Society for Mass Spectrometry},
	volume = {19},
	number = {12},
	year = {2008},
	note = {ISI Document Delivery No.: 385IWTimes Cited: 2Cited Reference Count: 36Wright, P. John Zhang, Jianmin Douglas, D. J.},
	month = {Dec},
	pages = {1906-1913},
	type = {Article},
	abstract = {At low pH in solutions of 50\% methanol, proteins form expanded denatured states (the "H" state). In 90\% methanol, proteins form expanded helical denatured states with artificial alpha-helices (the "H-c" state). Gas-phase ions of ubiquitin, cytochrome c, apomyoglobin, and native and disulfide-reduced beta-lactoglobulin were formed by electrospray ionization (EST) of the proteins from the H and H-c states in solution. Both states in solution produce the same charge states in EST. The conformations of the ions were studied with cross section measurements and gas-phase H/D exchange experiments. The cross sections show that the ions retain considerable folded structure. For a given protein and given charge state, ions produced from the H and H-c states showed the same cross sections (within similar to 1\%). Ions of cytochrome c, apomyoglobin, and native and reduced beta-lactoglobulin of a given charge state showed no differences in H/D exchange level when produced from the H or H-c state. However, ubiquitin ions produced from the H-c state consistently exchange fewer (similar to 13\%) hydrogens than ions produced from the H state, suggesting that in this case the gas-phase protein ions retain some memory of their solution conformations. (J Am Soc Mass Spectrom 2008, 19, 1906-1913) (c) 2008 Published by Elsevier Inc. on behalf of American Society for Mass Spectrometry},
	keywords = {CIRCULAR-DICHROISM, COLLISION CROSS-SECTIONS, H/D EXCHANGE, HYDROGEN/DEUTERIUM EXCHANGE, IONIZATION MASS-SPECTROMETRY, MYOGLOBIN, OF-FLIGHT, PROTEIN IONS, STABILITY, SYSTEM, TRAP},
	isbn = {1044-0305},
	url = {<Go to ISI>://000261808900023},
	author = {Wright, P. J. and Zhang, J. M. and Douglas, D. J.}
}
@article {1483,
	title = {Coulomb effects in binding of heme in gas-phase ions of myoglobin},
	journal = {Rapid Communications in Mass Spectrometry},
	volume = {20},
	number = {2},
	year = {2006},
	note = {ISI Document Delivery No.: 003PGTimes Cited: 3Cited Reference Count: 31},
	pages = {111-117},
	type = {Article},
	abstract = {Coulomb effects in binding of heme in gas-phase holomyoglobin ions are studied. Positive and negative ions are formed from solution myoglobin with Fe2+ (ferromyoglobin) and Fe3+ (ferrimyoglobin). The energy that must be added to the resulting holomyoglobin ions to cause heme loss has been measured by triple-quadrupole tandem mass spectrometry. With negative ions, neutral heme is lost regardless of the charge state of Fe in solution. It is likely that the Fe3+ is reduced to Fe2+ in the negative electrospray process. With positive ions, predominantly neutral heme loss is observed with ions formed from ferromyoglobin in solution, and positive heme loss with ions formed from ferrimyoglobin in solution. The energies required to induce neutral heme loss are similar for positive and negative ions. The energies required to induce charged heme loss from positive holomyoglobin ions are significantly less. Coulomb repulsion between the charged heme and charged protein appears to lower the barrier for heme loss. These results are consistent with a simple model potential with a long-range Coulomb repulsion and short-range attraction between the heme and protein. Copyright (c) 2005 John Wiley \& Sons, Ltd.},
	keywords = {B(5), COLLISION CROSS-SECTIONS, CYTOCHROME, DISSOCIATION, ELECTROSTATIC INTERACTIONS, GLOBIN COMPLEXES, HOLOMYOGLOBIN, IONIZATION-MASS-SPECTROMETRY, PROTEINS, STABILITY, ZN-MYOGLOBIN},
	isbn = {0951-4198},
	url = {<Go to ISI>://000234693500006},
	author = {Mark, K. J. and Douglas, D. J.}
}
@article {1283,
	title = {Nonequilibrium distribution functions for general rigid bodies in axially symmetric environments},
	journal = {Physical Review A},
	volume = {72},
	number = {3},
	year = {2005},
	note = {ISI Document Delivery No.: 969IRTimes Cited: 0Cited Reference Count: 20},
	month = {Sep},
	pages = {10},
	type = {Article},
	abstract = {A vector rho is introduced in such a manner that the equilibrium rotational distribution function for a general rigid body has a simple quadratic form both from a body-fixed and space-fixed frame of reference. It is shown that when considering nonequilibrium distribution functions, representations employing the components of rho generalize more easily than those employing the components of the angular momentum or angular velocity, and lead to forms with greater accuracy. The behavior of rho and its relation to the angular momentum of the system is explored in some detail. Comparisons are made with distribution functions generated from molecular dynamics simulations of H2O+ drifting in a helium bath gas under the influence of a uniform electric field.},
	keywords = {ALIGNMENT, COLLISION CROSS-SECTIONS, HELIUM, IONS, MOBILITIES, MOLECULAR-DYNAMICS, POTENTIAL-ENERGY SURFACES, ROTATIONAL, SCATTERING, SUPERSONIC EXPANSIONS, VELOCITY},
	isbn = {1050-2947},
	url = {<Go to ISI>://000232228300102},
	author = {Thachuk, M.}
}
@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.}
}
