Partitioning of Solvent Effects and Intrinsic Interactions in Biological Recognition

Kitova, Elena N.; Bundle, David R.; Klassen, John S.

doi:10.1002/anie.200353051

Cited by 22 publications

(20 citation statements)

References 21 publications

(24 reference statements)

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“…As discussed by Rodgers and Armentrout and Kitova and Klassen, the potential energy surface for noncovalent bond cleavage has a staircase appearance; that is, there should be no reverse activation barriers and endothermic noncovalent complex dissociation generally proceeds once the available energy exceeds the thermodynamic threshold. In the above CAD experiments, in which all ligands were dissociated (Figure ), we thus probed thermodynamic complex stability even though the energy values obtained from the E 50 analysis are relative rather than absolute …”

Section: Resultsmentioning

confidence: 99%

Interactions of Protonated Guanidine and Guanidine Derivatives with Multiply Deprotonated RNA Probed by Electrospray Ionization and Collisionally Activated Dissociation

2017

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Interactions of ribonucleic acid (RNA) with guanidine and guanidine derivatives are important features in RNA–protein and RNA–drug binding. Here we have investigated noncovalently bound complexes of an 8‐nucleotide RNA and six different ligands, all of which have a guanidinium moiety, by using electrospray ionization (ESI) and collisionally activated dissociation (CAD) mass spectrometry (MS). The order of complex stability correlated almost linearly with the number of ligand atoms that can potentially be involved in hydrogen‐bond or salt‐bridge interactions with the RNA, but not with the proton affinity of the ligands. However, ligand dissociation of the complex ions in CAD was generally accompanied by proton transfer from ligand to RNA, which indicated conversion of salt‐bridge into hydrogen‐bond interactions. The relative stabilities and dissociation pathways of [RNA+m L−n H]n− complexes with different stoichiometries (m=1–5) and net charge (n= 2–5) revealed both specific and unspecific ligand binding to the RNA.

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Section: Resultsmentioning

confidence: 99%

Interactions of Protonated Guanidine and Guanidine Derivatives with Multiply Deprotonated RNA Probed by Electrospray Ionization and Collisionally Activated Dissociation

2017

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“…Instead, the stability of protein complexes in the gas phase can only be assessed from measurements of their dissociation kinetics (for cleavage of the noncovalent intersubunit interactions). When performed under thermal conditions, the gas-phase kinetic measurements allow for the determination of the Arrhenius activation parameters for dissociation, which can be compared directly with the enthalpies and entropies of association determined in solution [46]. To evaluate the stability of the Stx2 B 5 nϩ ions, Arrhenius activation parameters were determined from the temperature dependence of the dissociation kinetics established from time-resolved BIRD data acquired for the B 5 ϩ12 and B 5 ϩ13 ions.…”

Section: Thermal Stability Of the Gaseous Stx B 5 Nϩ Ionsmentioning

confidence: 99%

Stability of the homopentameric b subunits of shiga toxins 1 and 2 in solution and the gas phase as revealed by nanoelectrospray fourier transform ion cyclotron resonance mass spectrometry

Kitova

Daneshfar

Marcato

et al. 2005

J. Am. Soc. Mass Spectrom.

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The assembly of the B subunits of Shiga toxins (Stx) 1 and 2 and the influence of solution conditions (protein concentration, temperature, pH, and ionic strength) on it are investigated using temperature-controlled nanoflow electrospray (nano-ES) ionization and Fourier-transform ion cyclotron resonance mass spectrometry. Despite the similar higher order structure predicted by X-ray crystallography analysis, the B 5 homopentamers of Stx1 and Stx2 exhibit differences in stability under the solution conditions investigated. At solution temperatures ranging from 0 to 60°C and subunit concentrations ranging from 5 to 85 M, the Stx1 B subunit exists almost entirely as the homopentamer in aqueous solutions, independent of the ionic strength. In contrast, the degree of assembly of Stx2 B subunit is strongly dependent on temperature, subunit concentration, and ionic strength. At subunit concentrations of more than 50 M, the Stx2 B subunit exists predominantly as a pentamer, although smaller multimers (dimer, trimer, and tetramer) are also evident. At lower concentrations, the Stx2 B subunit exists predominantly as monomer and dimer. The relative abundance of multimeric species of the Stx2 B subunit was insensitive to the ion source conditions, suggesting that gas-phase dissociation of the pentamer ions in the source does not influence the mass spectrum. Blackbody infrared radiative dissociation of the protonated B 5 ions of Stx2 at the ϩ12 and ϩ13 charge states proceeds, at reaction temperatures of 120 to 180°C, predominantly by the ejection of a single subunit from the complex. Dissociation into dimer and trimer ions constitutes a minor pathway. It follows that the dimer and trimer ions and, likely, the monomer ions observed in the nano-ES mass spectra of Stx2 B subunit originated in solution and not from gas-phase reactions. It is concluded that, under the solution conditions investigated, the homopentamer of Stx2 B subunit is thermodynamically less stable than that of Stx1 B subunit. Arrhenius activation parameters determined for the protonated Stx2 B 5 ions at the ϩ12 and ϩ13 charge states were compared with values reported for the corresponding B 5 ions of Stx1 B subunit. In contrast to the differential stability of the Stx1 and Stx2 B pentamers in solution, the dissociation activation energies (E a ) determined for the gaseous complexes are indistinguishable at a given charge state. The similarity in the E a values suggests that the protonated pentamer ions of both toxins are stabilized by similar intersubunit interactions in the gas phase, a result that is in agreement with the X-ray crystal structures of the holotoxins. (J Am Soc Mass Spectrom 2005, 16, 1957

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“…E-mail address: v.gabelica@ulg.ac.be (V. Gabelica). purely intermolecular interactions in the absence of solvent [5].…”

Section: Introductionmentioning

confidence: 99%

Positive and negative ion mode ESI-MS and MS/MS for studying drug–DNA complexes

Rosu

Pirotte

Pauw

et al. 2006

International Journal of Mass Spectrometry

100

142

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Partitioning of Solvent Effects and Intrinsic Interactions in Biological Recognition

Cited by 22 publications

References 21 publications

Interactions of Protonated Guanidine and Guanidine Derivatives with Multiply Deprotonated RNA Probed by Electrospray Ionization and Collisionally Activated Dissociation

Interactions of Protonated Guanidine and Guanidine Derivatives with Multiply Deprotonated RNA Probed by Electrospray Ionization and Collisionally Activated Dissociation

Stability of the homopentameric b subunits of shiga toxins 1 and 2 in solution and the gas phase as revealed by nanoelectrospray fourier transform ion cyclotron resonance mass spectrometry

Positive and negative ion mode ESI-MS and MS/MS for studying drug–DNA complexes

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