Entrapment of amino acids in gas phase surfactant assemblies:The case of tryptophan confined in positively charged (1 R ,2 S ) ‐ dodecyl (2 ‐ hydroxy ‐ 1 ‐ methyl ‐ 2 ‐ phenylethyl) dimethylammonium bromide aggregates

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Abstract

The ability of positively charged aggregates of the surfactant (1R,2S) ‐ dodecyl(2 ‐ hydroxy ‐ 1 ‐ methyl ‐ 2 ‐ phenylethyl)dimethylammonium bromide (DMEB) to incorporate D ‐ tryptophan or L ‐ tryptophan in the gas phase has been investigated by electrospray ion mobility mass spectrometry (ESI ‐ IM ‐ MS). Strongly impacted by the pH of the electrosprayed solutions, both protonated (T+) and deprotonated (T−) tryptophan are effectively included into the aggregates, whereas, tryptophan in zwitterionic (T0) form is practically absent in singly charged DMEB aggregates but can be found in multiply charged ones. The ability to incorporate tryptophan increases with the aggregation number and charge state of aggregates. More than 1 trypto- phan species can be entrapped (aggregates including up to 5 tryptophan are observed). Collision induced dissociation experiments performed on the positively singly charged DMEB hexamer containing 1 T− show that at low collision energies the loss of a DMEB molecule is preferred with respect to the loss of the DMEB cation plus T−species which, in turn, is preferred with respect to the loss of mere tryptophan, suggesting that the deprotonated amino acid is preferentially located in proximity of a DMEB head group and with the ionic moiety pointing towards the core of the aggregate. The analysis of the collision cross sections (CCS) of bare and tryptophan containing aggregates allowed evaluating the contributions of tryptophan and bromide ions to the total aggregate CCS. No significant discrimination between D ‐ tryptophan and L ‐ tryptophan by the chiral DMEB aggregates has been evidenced by mass spectra data, CID experiments, and CCS values.
Lingua originaleEnglish
pagine (da-a)681-688
Numero di pagine8
RivistaJournal of Mass Spectrometry
Volume52
Stato di pubblicazionePublished - 2017

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Bromides
Surface-Active Agents
Tryptophan
Gases
Amino Acids
Ions
Mass spectrometry
Cations
Agglomeration
Experiments
Molecules

All Science Journal Classification (ASJC) codes

  • Spectroscopy

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title = "Entrapment of amino acids in gas phase surfactant assemblies:The case of tryptophan confined in positively charged (1 R ,2 S ) ‐ dodecyl (2 ‐ hydroxy ‐ 1 ‐ methyl ‐ 2 ‐ phenylethyl) dimethylammonium bromide aggregates",
abstract = "The ability of positively charged aggregates of the surfactant (1R,2S) ‐ dodecyl(2 ‐ hydroxy ‐ 1 ‐ methyl ‐ 2 ‐ phenylethyl)dimethylammonium bromide (DMEB) to incorporate D ‐ tryptophan or L ‐ tryptophan in the gas phase has been investigated by electrospray ion mobility mass spectrometry (ESI ‐ IM ‐ MS). Strongly impacted by the pH of the electrosprayed solutions, both protonated (T+) and deprotonated (T−) tryptophan are effectively included into the aggregates, whereas, tryptophan in zwitterionic (T0) form is practically absent in singly charged DMEB aggregates but can be found in multiply charged ones. The ability to incorporate tryptophan increases with the aggregation number and charge state of aggregates. More than 1 trypto- phan species can be entrapped (aggregates including up to 5 tryptophan are observed). Collision induced dissociation experiments performed on the positively singly charged DMEB hexamer containing 1 T− show that at low collision energies the loss of a DMEB molecule is preferred with respect to the loss of the DMEB cation plus T−species which, in turn, is preferred with respect to the loss of mere tryptophan, suggesting that the deprotonated amino acid is preferentially located in proximity of a DMEB head group and with the ionic moiety pointing towards the core of the aggregate. The analysis of the collision cross sections (CCS) of bare and tryptophan containing aggregates allowed evaluating the contributions of tryptophan and bromide ions to the total aggregate CCS. No significant discrimination between D ‐ tryptophan and L ‐ tryptophan by the chiral DMEB aggregates has been evidenced by mass spectra data, CID experiments, and CCS values.",
author = "Leopoldo Ceraulo and David Bongiorno and Serena Indelicato and Valentina Calabrese and {Liveri, V.}",
year = "2017",
language = "English",
volume = "52",
pages = "681--688",
journal = "Journal of Mass Spectrometry",
issn = "1076-5174",
publisher = "John Wiley and Sons Ltd",

}

TY - JOUR

T1 - Entrapment of amino acids in gas phase surfactant assemblies:The case of tryptophan confined in positively charged (1 R ,2 S ) ‐ dodecyl (2 ‐ hydroxy ‐ 1 ‐ methyl ‐ 2 ‐ phenylethyl) dimethylammonium bromide aggregates

AU - Ceraulo, Leopoldo

AU - Bongiorno, David

AU - Indelicato, Serena

AU - Calabrese, Valentina

AU - Liveri, V.

PY - 2017

Y1 - 2017

N2 - The ability of positively charged aggregates of the surfactant (1R,2S) ‐ dodecyl(2 ‐ hydroxy ‐ 1 ‐ methyl ‐ 2 ‐ phenylethyl)dimethylammonium bromide (DMEB) to incorporate D ‐ tryptophan or L ‐ tryptophan in the gas phase has been investigated by electrospray ion mobility mass spectrometry (ESI ‐ IM ‐ MS). Strongly impacted by the pH of the electrosprayed solutions, both protonated (T+) and deprotonated (T−) tryptophan are effectively included into the aggregates, whereas, tryptophan in zwitterionic (T0) form is practically absent in singly charged DMEB aggregates but can be found in multiply charged ones. The ability to incorporate tryptophan increases with the aggregation number and charge state of aggregates. More than 1 trypto- phan species can be entrapped (aggregates including up to 5 tryptophan are observed). Collision induced dissociation experiments performed on the positively singly charged DMEB hexamer containing 1 T− show that at low collision energies the loss of a DMEB molecule is preferred with respect to the loss of the DMEB cation plus T−species which, in turn, is preferred with respect to the loss of mere tryptophan, suggesting that the deprotonated amino acid is preferentially located in proximity of a DMEB head group and with the ionic moiety pointing towards the core of the aggregate. The analysis of the collision cross sections (CCS) of bare and tryptophan containing aggregates allowed evaluating the contributions of tryptophan and bromide ions to the total aggregate CCS. No significant discrimination between D ‐ tryptophan and L ‐ tryptophan by the chiral DMEB aggregates has been evidenced by mass spectra data, CID experiments, and CCS values.

AB - The ability of positively charged aggregates of the surfactant (1R,2S) ‐ dodecyl(2 ‐ hydroxy ‐ 1 ‐ methyl ‐ 2 ‐ phenylethyl)dimethylammonium bromide (DMEB) to incorporate D ‐ tryptophan or L ‐ tryptophan in the gas phase has been investigated by electrospray ion mobility mass spectrometry (ESI ‐ IM ‐ MS). Strongly impacted by the pH of the electrosprayed solutions, both protonated (T+) and deprotonated (T−) tryptophan are effectively included into the aggregates, whereas, tryptophan in zwitterionic (T0) form is practically absent in singly charged DMEB aggregates but can be found in multiply charged ones. The ability to incorporate tryptophan increases with the aggregation number and charge state of aggregates. More than 1 trypto- phan species can be entrapped (aggregates including up to 5 tryptophan are observed). Collision induced dissociation experiments performed on the positively singly charged DMEB hexamer containing 1 T− show that at low collision energies the loss of a DMEB molecule is preferred with respect to the loss of the DMEB cation plus T−species which, in turn, is preferred with respect to the loss of mere tryptophan, suggesting that the deprotonated amino acid is preferentially located in proximity of a DMEB head group and with the ionic moiety pointing towards the core of the aggregate. The analysis of the collision cross sections (CCS) of bare and tryptophan containing aggregates allowed evaluating the contributions of tryptophan and bromide ions to the total aggregate CCS. No significant discrimination between D ‐ tryptophan and L ‐ tryptophan by the chiral DMEB aggregates has been evidenced by mass spectra data, CID experiments, and CCS values.

UR - http://hdl.handle.net/10447/243612

UR - http://onlinelibrary.wiley.com/doi/10.1002/jms.3972/epdf

M3 - Article

VL - 52

SP - 681

EP - 688

JO - Journal of Mass Spectrometry

JF - Journal of Mass Spectrometry

SN - 1076-5174

ER -