scholarly journals LILBID laser dissociation curves: a mass spectrometry-based method for the quantitative assessment of dsDNA binding affinities

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Phoebe Young ◽  
Genia Hense ◽  
Carina Immer ◽  
Jens Wöhnert ◽  
Nina Morgner
Keyword(s):  
Mass Spectrometry ◽  
Binding Affinity ◽  
Dissociation Constants ◽  
Laser Energy ◽  
Native Mass Spectrometry ◽  
Aqueous Sample ◽  
Binding Affinities ◽  
Melting Temperatures ◽  
Melting Curves ◽  
Dissociation Curves

AbstractOne current goal in native mass spectrometry is the assignment of binding affinities to noncovalent complexes. Here we introduce a novel implementation of the existing laser-induced liquid bead ion desorption (LILBID) mass spectrometry method: this new method, LILBID laser dissociation curves, assesses binding strengths quantitatively. In all LILBID applications, aqueous sample droplets are irradiated by 3 µm laser pulses. Variation of the laser energy transferred to the droplet during desorption affects the degree of complex dissociation. In LILBID laser dissociation curves, laser energy transfer is purposely varied, and a binding affinity is calculated from the resulting complex dissociation. A series of dsDNAs with different binding affinities was assessed using LILBID laser dissociation curves. The binding affinity results from the LILBID laser dissociation curves strongly correlated with the melting temperatures from UV melting curves and with dissociation constants from isothermal titration calorimetry, standard solution phase methods. LILBID laser dissociation curve data also showed good reproducibility and successfully predicted the melting temperatures and dissociation constants of three DNA sequences. LILBID laser dissociation curves are a promising native mass spectrometry binding affinity method, with reduced time and sample consumption compared to melting curves or titrations.

scholarly journals Protein Secondary Structure Affects Glycan Clustering in Native Mass Spectrometry

Life ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 554
Author(s):  
Hao Yan ◽  
Julia Lockhauserbäumer ◽  
Gergo Peter Szekeres ◽  
Alvaro Mallagaray ◽  
Robert Creutznacher ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Dissociation Constants ◽  
Protein Secondary Structure ◽  
Binding Pocket ◽  
Native Mass Spectrometry ◽  
Resonance Spectroscopy ◽  
Blood Group Antigens ◽  
Binding Affinities ◽  
Native Ms ◽  
Capsid Protein Vp1

Infection by the human noroviruses (hNoV), for the vast majority of strains, requires attachment of the viral capsid to histo blood group antigens (HBGAs). The HBGA-binding pocket is formed by dimers of the protruding domain (P dimers) of the capsid protein VP1. Several studies have focused on HBGA binding to P dimers, reporting binding affinities and stoichiometries. However, nuclear magnetic resonance spectroscopy (NMR) and native mass spectrometry (MS) analyses yielded incongruent dissociation constants (KD) for the binding of HBGAs to P dimers and, in some cases, disagreed on whether glycans bind at all. We hypothesized that glycan clustering during electrospray ionization in native MS critically depends on the physicochemical properties of the protein studied. It follows that the choice of a reference protein is crucial. We analysed carbohydrate clustering using various P dimers and eight non-glycan binding proteins serving as possible references. Data from native and ion mobility MS indicate that the mass fraction of β-sheets has a strong influence on the degree of glycan clustering. Therefore, the determination of specific glycan binding affinities from native MS must be interpreted cautiously.

scholarly journals Protein secondary structure affects glycan clustering in native mass spectrometry

2021 ◽  
Author(s):  
Hao Yan ◽  
Julia Lockhauserb&aumlumer ◽  
Gergo Peter Szekeres ◽  
Alvaro Mallagaray ◽  
Robert Creutznacher ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Dissociation Constants ◽  
Protein Secondary Structure ◽  
Binding Pocket ◽  
Native Mass Spectrometry ◽  
Resonance Spectroscopy ◽  
Blood Group Antigens ◽  
Binding Affinities ◽  
Native Ms ◽  
Capsid Protein Vp1

Infection with human noroviruses (hNoV) for the vast majority of strains requires attachment of the viral capsid to histo blood group antigens (HBGA). The HBGA binding pocket is formed by dimers of the protruding domain (P dimers) of the capsid protein VP1. Several studies have focused on HBGA binding to P dimers, reporting binding affinities and stoichiometries. However, nuclear magnetic resonance spectroscopy (NMR) and native mass spectrometry (MS) analyses yielded incongruent dissociation constants (KD) for binding of HBGAs to P dimers and, in some cases, disagreed whether glycans bind at all. We hypothesized that glycan clustering during electrospray ionization in native MS critically depends on the physicochemical properties of the protein studied. It follows that the choice of the reference protein is crucial. We analyzed carbohydrate clustering using various P dimers and eight non-glycan binding proteins serving as possible references. Data from native and ion mobility MS indicate that the mass fraction of β-sheet has a strong influence on the degree of glycan clustering. Therefore, the determination of specific glycan binding affinities from native MS must be interpreted cautiously.

scholarly journals Nanoscale Ion Emitters in Native Mass Spectrometry for Measuring Ligand–Protein Binding Affinities

2019 ◽  
Vol 5 (2) ◽  
pp. 308-318 ◽  
Author(s):  
Giang T. H. Nguyen ◽  
Thinh N. Tran ◽  
Matthew N. Podgorski ◽  
Stephen G. Bell ◽  
Claudiu T. Supuran ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Protein Binding ◽  
Native Mass Spectrometry ◽  
Binding Affinities

Rapid Online Buffer Exchange: A Method for Screening of Proteins, Protein Complexes, and Cell Lysates by Native Mass Spectrometry

2019 ◽  
Author(s):  
Zachary VanAernum ◽  
Florian Busch ◽  
Benjamin J. Jones ◽  
Mengxuan Jia ◽  
Zibo Chen ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
High Speed ◽  
Structural Information ◽  
Protein Complexes ◽  
High Sensitivity ◽  
Native Mass Spectrometry ◽  
Structural Features ◽  
Consumer Products ◽  
Cell Lysates ◽  
Protein Expression And Purification

It is important to assess the identity and purity of proteins and protein complexes during and after protein purification to ensure that samples are of sufficient quality for further biochemical and structural characterization, as well as for use in consumer products, chemical processes, and therapeutics. Native mass spectrometry (nMS) has become an important tool in protein analysis due to its ability to retain non-covalent interactions during measurements, making it possible to obtain protein structural information with high sensitivity and at high speed. Interferences from the presence of non-volatiles are typically alleviated by offline buffer exchange, which is timeconsuming and difficult to automate. We provide a protocol for rapid online buffer exchange (OBE) nMS to directly screen structural features of pre-purified proteins, protein complexes, or clarified cell lysates. Information obtained by OBE nMS can be used for fast (<5 min) quality control and can further guide protein expression and purification optimization.

Native Mass Spectrometry-Based Screening for Optimal Sample Preparation in Single Particle Cryo-EM

2020 ◽  
Author(s):  
Paul Dominic B. Olinares ◽  
Jin Young Kang ◽  
Eliza Llewellyn ◽  
Courtney Chiu ◽  
James Chen ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Sample Preparation ◽  
Single Particle ◽  
Native Mass Spectrometry ◽  
Optimal Sample

scholarly journals SMPLIP-Score: predicting ligand binding affinity from simple and interpretable on-the-fly interaction fingerprint pattern descriptors

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Surendra Kumar ◽  
Mi-hyun Kim
Keyword(s):  
Ligand Binding ◽  
Binding Affinity ◽  
Scoring Functions ◽  
Binding Affinities ◽  
Ligand Interaction ◽  
Fingerprint Pattern ◽  
Comparable Performance ◽  
Direct Interpretation ◽  
Benchmark Datasets ◽  
Complex Features

AbstractIn drug discovery, rapid and accurate prediction of protein–ligand binding affinities is a pivotal task for lead optimization with acceptable on-target potency as well as pharmacological efficacy. Furthermore, researchers hope for a high correlation between docking score and pose with key interactive residues, although scoring functions as free energy surrogates of protein–ligand complexes have failed to provide collinearity. Recently, various machine learning or deep learning methods have been proposed to overcome the drawbacks of scoring functions. Despite being highly accurate, their featurization process is complex and the meaning of the embedded features cannot directly be interpreted by human recognition without an additional feature analysis. Here, we propose SMPLIP-Score (Substructural Molecular and Protein–Ligand Interaction Pattern Score), a direct interpretable predictor of absolute binding affinity. Our simple featurization embeds the interaction fingerprint pattern on the ligand-binding site environment and molecular fragments of ligands into an input vectorized matrix for learning layers (random forest or deep neural network). Despite their less complex features than other state-of-the-art models, SMPLIP-Score achieved comparable performance, a Pearson’s correlation coefficient up to 0.80, and a root mean square error up to 1.18 in pK units with several benchmark datasets (PDBbind v.2015, Astex Diverse Set, CSAR NRC HiQ, FEP, PDBbind NMR, and CASF-2016). For this model, generality, predictive power, ranking power, and robustness were examined using direct interpretation of feature matrices for specific targets.

scholarly journals DNA G-quadruplexes for native mass spectrometry in potassium: a database of validated structures in electrospray-compatible conditions

2021 ◽  
Author(s):  
Anirban Ghosh ◽  
Eric Largy ◽  
Valérie Gabelica
Keyword(s):  
Mass Spectrometry ◽  
Drug Targets ◽  
Native Mass Spectrometry ◽  
Drug Binding ◽  
Quadruplex Dna ◽  
Dna Structures ◽  
Nmr Structures ◽  
G Quadruplex ◽  
Screening Assays

Abstract G-quadruplex DNA structures have become attractive drug targets, and native mass spectrometry can provide detailed characterization of drug binding stoichiometry and affinity, potentially at high throughput. However, the G-quadruplex DNA polymorphism poses problems for interpreting ligand screening assays. In order to establish standardized MS-based screening assays, we studied 28 sequences with documented NMR structures in (usually ∼100 mM) potassium, and report here their circular dichroism (CD), melting temperature (Tm), NMR spectra and electrospray mass spectra in 1 mM KCl/100 mM trimethylammonium acetate. Based on these results, we make a short-list of sequences that adopt the same structure in the MS assay as reported by NMR, and provide recommendations on using them for MS-based assays. We also built an R-based open-source application to build and consult a database, wherein further sequences can be incorporated in the future. The application handles automatically most of the data processing, and allows generating custom figures and reports. The database is included in the g4dbr package (https://github.com/EricLarG4/g4dbr) and can be explored online (https://ericlarg4.github.io/G4_database.html).

scholarly journals Development of a target identification approach using native mass spectrometry

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Miaomiao Liu ◽  
Wesley C. Van Voorhis ◽  
Ronald J. Quinn
Keyword(s):  
Mass Spectrometry ◽  
Protein Interactions ◽  
Target Identification ◽  
Native Mass Spectrometry ◽  
Pharmaceutical Drugs ◽  
Ligand Complex ◽  
Experimental Conditions ◽  
Protein Mixture ◽  
Native Ms ◽  
Drug Target Identification

AbstractA key step in the development of new pharmaceutical drugs is the identification of the molecular target and distinguishing this from all other gene products that respond indirectly to the drug. Target identification remains a crucial process and a current bottleneck for advancing hits through the discovery pipeline. Here we report a method, that takes advantage of the specific detection of protein–ligand complexes by native mass spectrometry (MS) to probe the protein partner of a ligand in an untargeted method. The key advantage is that it uses unmodified small molecules for binding and, thereby, it does not require labelled ligands and is not limited by the chemistry required to tag the molecule. We demonstrate the use of native MS to identify known ligand–protein interactions in a protein mixture under various experimental conditions. A protein–ligand complex was successfully detected between parthenolide and thioredoxin (PfTrx) in a five-protein mixture, as well as when parthenolide was mixed in a bacterial cell lysate spiked with PfTrx. We provide preliminary data that native MS could be used to identify binding targets for any small molecule.

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