Enhancing performance of liquid sample desorption electrospray ionization mass spectrometry using trap and capillary columns

Cheng, Shan; Wang, Jun; Cai, Yong; Loo, Joseph A.; Chen, Hao

doi:10.1016/j.ijms.2015.09.010

“…[17,28] Protein ligand binding experiments have also been achieved with reactions taking place by mixing in solution in al iquid sample DESI approach [6] rather than by interaction following protein deposition on the planar target as shown here.M oreover kinetic approaches have been developed using mixing experiments to monitor the small molecules released during enzymatic cleavage by means of liquid DESI and have increased the range of buffers that can be used. [29,30] Our native DESI approach is largely restricted to volatile buffers and detergents that have been optimised for native MS.A further limitation is imposed by the fact that ligands are observed directly bound to proteins desorbed from ap lanar surface,h igh-resolution MS is therefore critical.…”

Section: Zuschriftenmentioning

confidence: 99%

Native Desorption Electrospray Ionization Liberates Soluble and Membrane Protein Complexes from Surfaces

Ambrose

¹

,

Housden

²

,

Gupta

³

et al. 2017

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Mass spectrometry (MS) applications for intact protein complexes typically require electrospray (ES) ionization and have not been achieved via direct desorption from surfaces. Desorption ES ionization (DESI) MS has however transformed the study of tissue surfaces through release and characterisation of small molecules. Motivated by the desire to screen for ligand binding to intact protein complexes we report the development of a native DESI platform. By establishing conditions that preserve non‐covalent interactions we exploit the surface to capture a rapid turnover enzyme–substrate complex and to optimise detergents for membrane protein study. We demonstrate binding of lipids and drugs to membrane proteins deposited on surfaces and selectivity from a mix of related agonists for specific binding to a GPCR. Overall therefore we introduce this native DESI platform with the potential for high‐throughput ligand screening of some of the most challenging drug targets including GPCRs.

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“…Cheng and co-workers extended the utility of sampling liquids using DESI by replacing the fused silica capillary used to supply the liquid to the spray with a trap column in order to desalt and enrich the analyte. The same approach was used with an enzyme-containing capillary for fast digestion of proteins before DESI analysis . The trap column simplified the analysis of low-level analytes in complex mixtures, while the latter modification hastened the identification of proteins.…”

Section: Electrospray-based Ambient Ionizationmentioning

confidence: 99%

Advances in Ionization for Mass Spectrometry

Peacock¹,

Zhang

²

,

Trimpin

³

2016

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“…Protein ligand binding experiments have also been achieved with reactions taking place by mixing in solution in a liquid sample DESI approach rather than by interaction following protein deposition on the planar target as shown here. Moreover kinetic approaches have been developed using mixing experiments to monitor the small molecules released during enzymatic cleavage by means of liquid DESI and have increased the range of buffers that can be used . Our native DESI approach is largely restricted to volatile buffers and detergents that have been optimised for native MS. A further limitation is imposed by the fact that ligands are observed directly bound to proteins desorbed from a planar surface, high‐resolution MS is therefore critical.…”

Section: Figurementioning

confidence: 99%

Native Desorption Electrospray Ionization Liberates Soluble and Membrane Protein Complexes from Surfaces

Ambrose

¹

,

Housden

²

,

Gupta

³

et al. 2017

View full text Add to dashboard Cite

Mass spectrometry (MS) applications for intact protein complexes typically require electrospray( ES) ionization and have not been achieved via direct desorption from surfaces.D esorption ES ionization (DESI) MS has however transformed the study of tissue surfaces through release and characterisation of small molecules.Motivated by the desire to screen for ligand binding to intact protein complexes we report the development of an ative DESI platform. By establishing conditions that preserve non-covalent interactions we exploit the surface to capture ar apid turnover enzyme-substrate complex and to optimise detergents for membrane protein study.W ed emonstrate binding of lipids and drugs to membrane proteins deposited on surfaces and selectivity from am ix of related agonists for specific binding to aG PCR. Overall therefore we introduce this native DESI platform with the potential for high-throughput ligand screening of some of the most challenging drug targets including GPCRs.A range of applications,i ncluding 2D imaging of small molecules and metabolites released from tissue cross-sections, has become possible with the introduction of powerful DESI approaches when coupled with MS. [1,2] Thep rimary goal of DESI applications has been to focus on the small molecules released, for example in the real-time detection of tumour tissue during surgical procedures. [3,4] While DESI has also been adapted to study large biomolecules,v ia the mixing of ES droplets and solution in ap rocess known as liquid DESI, [5,6] it has not yet been applied to proteins deposited on surfaces and desorbed in solutions that retain their native state interactions.D espite considerable progress in applications of non-denaturing or native MS (nMS) of soluble [7][8][9] and membrane embedded proteins [10] the possibility of effectively "lifting" intact complexes from surfaces is desirable since many high throughput technologies then become accessible.[11] Moreover the lipid distribution in natural membranes is essentially planar and asymmetric with varying spatial and temporal arrangements in the vicinity of embedded protein complexes.[12] Thel ipid distribution and the desire for as urface technology that is also able to analyse membrane proteins motivated us to develop amodified DESI approach capable of releasing folded protein molecules from planar surfaces and to construct an interface that we could couple to ah igh-resolution Orbitrap MS optimised for high mass transmission [13] of membrane proteins. [14] We demonstrate the potential of this methodology in three ways 1) by capturing transient protein substrate products 2) by screening for optimal solution/purification conditions using picoMoles of membrane and soluble proteins and 3) by carrying out ligand binding experiments on planar surfaces.We modified the design of the original DESI set-up [1] and with our custom-built ion source,ESdevice and sample stage coupled our interface to an Orbitrap Q-Exactive (Figure 1a and Supporting Information Figure S1). We found that signal i...

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Enhancing performance of liquid sample desorption electrospray ionization mass spectrometry using trap and capillary columns

Cited by 9 publications

References 51 publications

Native Desorption Electrospray Ionization Liberates Soluble and Membrane Protein Complexes from Surfaces

Native Desorption Electrospray Ionization Liberates Soluble and Membrane Protein Complexes from Surfaces

Advances in Ionization for Mass Spectrometry

Native Desorption Electrospray Ionization Liberates Soluble and Membrane Protein Complexes from Surfaces

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