Cation−π Interactions in Sodiated Phenylalanine Complexes:  Is Phenylalanine in the Charge-Solvated or Zwitterionic Form?

Siu, Fung Ming; Ling, Ngai; Tsang, Chun Wai

doi:10.1021/ja0056872

Cited by 61 publications

(115 citation statements)

References 16 publications

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“…The measured binding energy values of the first water molecule in these three complexes are similar (12.6 to 13.3 kcal/ mol) and close to that calculated [7] for the zwitterionic form of ValK ϩ (H 2 O), which is lower than that for the nonzwitterionic structure, Table 1. Therefore, although speculative, it seems very likely that GlyK ϩ (H 2 O) n ϭ 1,2 and AlaK ϩ (H 2 O) n ϭ 1,2 formed in the present experiments have the structures analogous to those of ValK ϩ (H 2 O) n ϭ 1,2 .…”

Section: Comparison With Other Resultssupporting

confidence: 80%

“…The literature provides water binding energies only for ValK ϩ (H 2 O) n ϭ 1,2 systems [7,25]. Williams and coworkers [7] showed, based on the BIRD technique, that the K ϩ ion in the ValK ϩ (H 2 O) complex is OO-coordinated.…”

Section: Comparison With Other Resultsmentioning

confidence: 99%

“…Williams and coworkers [7] showed, based on the BIRD technique, that the K ϩ ion in the ValK ϩ (H 2 O) complex is OO-coordinated. However, from these experiments they were unable to distinguish whether the valine in this system was nonzwitterionic 1, or zwitterionic 2, in form.…”

Section: Comparison With Other Resultsmentioning

confidence: 99%

“…They play an important role in several biochemical functions such as enzyme regulation, transfer of metal ions from intracellular to extracellular environments, electrical excitability of nerves, stabilization of DNA structures and so on [1]. Therefore, the interaction between alkali metal cations and various amino acids (AAs) has attracted considerable attention, and many experimental and theoretical studies have been conducted [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. These studies show that K ϩ binds to AAs quite differently than Na ϩ .…”

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confidence: 99%

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Hydration of potassiated amino acids in the gas phase

Wincel

2007

J. Am. Soc. Mass Spectrom.

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The thermochemistry of stepwise hydration of several potassiated amino acids was studied by measuring the gas-phase equilibria, AAK ϩ (H 2 O) nϪ1 ϩ H 2 O ϭ AAK ϩ (H 2 O) n (AA ϭ Gly, AL, Val, Met, Pro, and Phe), using a high-pressure mass spectrometer. The AAK ϩ ions were obtained by electrospray and the equilibrium constants K nϪ1,n were measured in a pulsed reaction chamber at 10 mbar bath gas, N 2 , containing a known partial pressure of water vapor. Determination of the equilibrium constants at different temperatures was used to obtain the ϩ and Na ϩ ions are the most abundant metal cations in living systems. They play an important role in several biochemical functions such as enzyme regulation, transfer of metal ions from intracellular to extracellular environments, electrical excitability of nerves, stabilization of DNA structures and so on [1]. Therefore, the interaction between alkali metal cations and various amino acids (AAs) has attracted considerable attention, and many experimental and theoretical studies have been conducted [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. These studies show that K ϩ binds to AAs quite differently than Na ϩ . For example, in the case of aliphatic AAs such as glycine (Gly), alanine (Ala), and valine (Val), the Na ϩ ion is coordinated to nitrogen and carbonyl oxygen (NO coordination) in the lowest energy conformers, while K ϩ prefers to bind to the carbonyl and hydroxyl oxygen atoms of the charge-solvated form (OO coordination) [6,8,10,16]. In proline (Pro), phenylalanine (Phe), and cysteine (Cys), the modes of K ϩ binding are similar to those of the corresponding Na ϩ complexes [3-5, 12, 20].Molecular dynamics simulations of a bacterial potassium ion channel reveal a significant selectivity filter for K ϩ compared with Na ϩ ions [21,22]. The different hydration state of Na ϩ and K ϩ in the channel inner pore is postulated to be a basic factor determining ionic selectivity [23,24]. Investigations into the relative energetics of noncovalent interactions between single amino acids, metal ions and water molecules could provide important information to explain ion channel function at a molecular level. Despite the considerable amount of experimental and theoretical studies that have been conducted on the binding of Na ϩ and K ϩ to amino acids, little data are available on the interactions of water molecules with metal ion/amino acid complexes. Because metal ions and biomolecules are normally surrounded by water in living systems, these interactions are of significant importance in understanding biological systems. Williams and coworkers [8,[25][26][27][28][29][30][31] studied the modes of metal ion and water binding in hydrated complexes of alkali metal cationized valine, glutamine, lysine, and ␣-methyl-proline using both black-␣ ␣ body infrared radiative dissociation (BIRD) experiments and theory. Armentrout et al. investigated the sequential bond energies of water to sodiated glycine [32] and proline [33] by threshold collision-induced dissociation ...

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Section: Comparison With Other Resultssupporting

confidence: 80%

Section: Comparison With Other Resultsmentioning

confidence: 99%

Section: Comparison With Other Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

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Hydration of potassiated amino acids in the gas phase

Wincel

2007

J. Am. Soc. Mass Spectrom.

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“…This correlation with the proton affinity of amino acids provided a way to predict the structural preferences of common amino acids in the gas phase. Other metal coordinated amino acids have been reported to stabilize the zwitterion including transition metals [35][36][37][38]. Rak et al even suggested that the attachment of an excess electron diminished the instability of zwitterionic amino acid [39].…”

mentioning

confidence: 99%

Zwitterion formation in gas-phase cyclodextrin complexes

Ahn

Cong

Lebrilla

et al. 2005

J. Am. Soc. Mass Spectrom.

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Protonated complexes of amino acids and underivatized ␤-cyclodextrin, produced by electrospray ionization and trapped in the Fourier transform mass spectrometer, undergo formation of ternary complexes when reacted with alkyl amine. Based on the reactivities of the protonated amino acid complexes with alkylamines, the reactivities of the corresponding amino acid esters, and partially derivatized ␤-cyclodextrin hosts, we conclude that the ternary complexes are salt-bridge zwitterionic species composed of amino acid zwitterions and protonated alkylamine all interacting with the hydroxyl groups on the narrow rim of the cyclodextrin. Molecular modeling calculations and experimental results suggest that the interactions of the amino acids with the rims contribute greatly to the formation of the zwitterionic species. (J Am Soc Mass Spectrom 2005, 16, 166 -175)

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Wechselwirkungen mit aromatischen Ringen in chemischen und biologischen Erkennungsprozessen

2003

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Zwischenmolekulare Wechselwirkungen unter Beteiligung aromatischer Ringe sind Schlüsselvorgänge sowohl in chemischen als auch in biologischen Erkennungsprozessen. Ihr Verständnis ist für das rationale Wirkstoffdesign und für die Leitstrukturoptimierung in der Medizinischen Chemie essenziell. Unterschiedliche Ansätze werden für ein tiefergehendes Verständnis der strukturellen und energetischen Parameter einzelner Erkennungsarten mit aromatischen Substraten verfolgt: erwähnt seien biologische Untersuchungen, Studien der molekularen Erkennung mit künstlichen Rezeptoren, Suchen in kristallographischen Datenbanken, Gasphasenstudien und theoretische Untersuchungen. Dieser Aufsatz versucht, diese Wissensgebiete zu vereinen und die aus zahlreichen Untersuchungen gewonnenen Erkenntnisse zusammenzufassen. Er widmet sich hauptsächlich Beispielen mit biologischer Relevanz mit dem Ziel, die für die Wirkstoffentwicklung wichtigen Kenntnisse der molekularen Erkennung zu vertiefen.

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Cation−π Interactions in Sodiated Phenylalanine Complexes: Is Phenylalanine in the Charge-Solvated or Zwitterionic Form?

Cited by 61 publications

References 16 publications

Hydration of potassiated amino acids in the gas phase

Hydration of potassiated amino acids in the gas phase

Zwitterion formation in gas-phase cyclodextrin complexes

Wechselwirkungen mit aromatischen Ringen in chemischen und biologischen Erkennungsprozessen

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