Mapping the CCL8:P672 interface using HDX-MS
Ontology highlight
ABSTRACT:
INSTRUMENT(S): SYNAPT G2-Si
ORGANISM(S): Rhipicephalus Pulchellus
SUBMITTER: 
Lucia Geis-Asteggiante
LAB HEAD: Shoumo Bhattacharya
PROVIDER: PXD019199 | Pride | 2020-05-29
REPOSITORIES: Pride
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| CCL8_1.raw.zip | Raw | |||
| CCL8_1_IA_final_peptide.csv | Csv | |||
| CCL8_3.raw.zip | Raw | |||
| CCL8_300s_1.raw.zip | Raw | |||
| CCL8_300s_2.raw.zip | Raw |
Items per page: 5 1 - 5 of 60 |
Similar Datasets
Project description:The conformational ensembles of G-protein coupled receptors (GPCRs) include inactive and active states. Spectroscopy techniques, including NMR, show that agonists, antagonists and other ligands shift the ensemble toward specific states depending on the pharmacological efficacy of the ligand. How receptors recognize ligands and the kinetic mechanism underlying this population shift is poorly understood. Here, we investigate the kinetic mechanism of neurotensin recognition by neurotensin receptor 1 (NTS1) using 19F-NMR, hydrogen-deuterium exchange mass spectrometry and stopped-flow fluorescence spectroscopy. Our results indicate slow-exchanging conformational heterogeneity on the extracellular surface of ligand-bound NTS1. Numerical analysis of the kinetic data of neurotensin binding to NTS1 shows that ligand recognition follows an induced fit mechanism, in which conformational changes occur after neurotensin binding. This approach is applicable to other GPCRs to provide insight into the kinetic regulation of ligand recognition by GPCRs.
2023-12-09 | PXD045464 | Pride
Project description:Mtr4 is a eukaryotic RNA helicase required for RNA decay by the nuclear exosome. Previous studies have shown how RNA enroute to the exosome threads through the highly conserved helicase core of Mtr4. Mtr4 also contains an arch domain, although details of potential interactions between the arch and RNA have been elusive. To understand the interaction of Saccharomyces cerevisiae Mtr4 with various RNAs, we have characterized RNA binding in solution using hydrogen-deuterium exchange mass spectrometry, and affinity and unwinding assays. We have identified RNA interactions within the helicase core that are consistent with existing structures and do not vary between tRNA, single-stranded RNA, and double-stranded RNA constructs. We have also identified novel RNA interactions with a region of the arch known as the fist or KOW. These interactions are important for RNA unwinding and vary in strength depending on RNA structure and length. They account for Mtr4 discrimination between different RNAs. These interactions further drive Mtr4 to adopt a closed conformation characterized by reduced dynamics of the arch arm and intra-domain contacts between the fist and helicase core.
2022-03-07 | PXD031962 | Pride
Project description:CD47 is the only 5-transmembrane (5-TM) spanning receptor of the immune system. Its extracellular domain (ECD) is a cell surface ‘marker of self’ that binds SIRPα and inhibits macrophage phagocytosis, and cancer immuno-therapy approaches in clinical trials are focused on blocking CD47/SIRPα interaction. Using hydrogen-deuterium exchange we show that CD47’s ECLR architecture, comprised of two extracellular loops and the SWF loop, creates a molecular environment stabilizing the ECD for presentation on the cell surface.
2021-07-15 | PXD026458 | Pride
Project description:TRAMP is a eukaryotic protein complex with RNA helicase and polyadenylase activity that marks and delivers a variety of RNA substrates to the nuclear exosome for degradation. Prior work has characterized binding of Trf4 and Air2 to the helicase core of Mtr4 and the regulation of both enzymatic activities in TRAMP. Air2 contains a conserved sequence that is predicted to bind the arch domain of Mtr4, though this interface is dispensable for TRAMP formation. To understand the interactions of the Saccharomyces cerevisiae TRAMP complex and its interactions with RNA, we have applied hydrogen-deuterium exchange mass spectrometry. We demonstrate that Air2 simultaneously binds the helicase core and the fist of Mtr4 in solution, constraining the arch to a conformation ready to bind RNA. We characterize the previously unknown interactions of Trf4 and Air2 with RNA and show how interactions with substrates are altered in TRAMP, supporting a mechanistic model for the enhancement of Mtr4 activity in TRAMP.
2024-12-11 | PXD053773 | Pride
Project description:Immunoglobulin light chain (LC) amyloidosis (AL) is a life-threatening human disease wherein free monoclonal LCs deposit in vital organs. To determine what makes some LCs amyloidogenic, we explored patient-based amyloidogenic and non-amyloidogenic recombinant LCs from the λ6 subtype prevalent in AL. Hydrogen-deuterium exchange mass spectrometry, structural stability, proteolysis, and amyloid growth studies revealed that the antigen-binding CDR1 loop is the least protected part in the variable domain of λ6 LC, particularly in the AL variant. N32T substitution in CRD1 is identified as a driver of amyloid formation. Substitution N32T increased the amyloidogenic propensity of CDR1 loop, decreased its protection in the native structure, and accelerated amyloid growth in the context of other AL substitutions. The destabilizing effects of N32T propagated across the molecule increasing its dynamics in regions ~30Å away from the substitution site. Such striking long-range effects of a conservative point substitution in a dynamic surface loop may be relevant to Ig function. Comparison of patient-derived and engineered proteins showed that N32T interactions with other substitution sites must contribute to amyloidosis. The results suggest that CDR1 is critical in amyloid formation by other λ6 LCs.
2021-11-25 | PXD026528 | Pride
Project description:During the analysis steps of hydrogen deuterium exchange (HDX) mass spectrometry (MS) there is an unavoidable loss of deuterons, or back-exchange. Understanding back-exchange is necessary to correct for loss during analysis, to calculate the absolute amount of exchange, and to ensure that deuterium recovery is as high as possible during LC-MS. Back-exchange can be measured and corrected for using a maximally deuterated species (here called maxD) in which the protein is deuterated at all backbone amide positions and analyzed with the same buffer components, %D2O, quenching conditions, and LC-MS parameters used during the analysis of other labeled samples. Here we describe a robust and broadly applicable protocol, using denaturation followed by deuteration, to prepare a maxD control sample in ~40 minutes. The protocol was evaluated with a number of proteins that varied in both size and folded structure. The relative fractional uptake and level of back-exchange with this protocol were both equivalent to those obtained with a previous protocol that requires much more time or one requiring isolation of peptic peptides prior to deuteration. Placing strong denaturation first in the protocol allowed maximum deuteration in a short time (~10 mins) with equal or more deuteration found in other methods. The absence of high temperatures and low pH during the deuteration step limited protein aggregation. This high-performance, fast, and easy to perform protocol should enhance routine preparation of maxD controls for both beginners and for challenging proteins.
2022-07-08 | PXD032924 | Pride
Project description:Imp9 is the primary importin for shuttling H2A-H2B from the cytoplasm to the nucleus. It employs an unusual mechanism where the binding of RanGTP is insufficient to release H2A-H2B. The resulting stable RanGTP•Imp9•H2A-H2B complex gains nucleosome assembly activity with H2A-H2B able to be deposited into an assembling nucleosome in vitro. Using hydrogen-deuterium exchange coupled with mass spectrometry (HDX), we show that Imp9 stabilizes H2A-H2B beyond the direct binding site, like other histone chaperones. HDX also shows that binding of RanGTP releases H2A-H2B contacts at Imp9 HEAT repeats 4-5, but not 18-19. DNA- and histone-binding surfaces of H2A-H2B are exposed in the ternary complex, facilitating nucleosome assembly. We also reveal that RanGTP has a weaker affinity for Imp9 when H2A-H2B is bound. Imp9 thus provides a connection between the nuclear import of H2A-H2B and its deposition into chromatin.
2023-06-02 | PXD037571 | Pride
Project description:The hexameric Cdc48 ATPase (p97 or VCP in mammals) cooperates with its cofactor Ufd1/Npl4 to extract polyubiquitinated proteins from membranes or macromolecular complexes for degradation by the proteasome. Here, we clarify how the Cdc48 complex unfolds its substrates and translocates polypeptides with branchpoints. The Cdc48 complex recognizes primarily polyubiquitin chains, rather than the attached substrate. Cdc48 and Ufd1/Npl4 cooperatively bind the polyubiquitin chain, resulting in the unfolding of one ubiquitin molecule (initiator). Next, the ATPase pulls on the initiator ubiquitin and moves all ubiquitin molecules linked to its C-terminus through the central pore of the hexameric double-ring, causing transient ubiquitin unfolding. When the ATPase reaches the isopeptide bond of the substrate, it can translocate and unfold both N- and C-terminal segments. Ubiquitins linked to the branchpoint of the initiator dissociate from Ufd1/Npl4 and move outside the central pore, resulting in the release of unfolded, polyubiquitinated substrate from Cdc48.
2022-01-19 | PXD027639 | Pride
Project description:BAX is a pro-apoptotic member of the BCL-2 family, which regulates the balance between cellular life and death. During homeostasis, BAX predominantly resides in the cytosol as a latent monomer but, in response to stress, transforms into an oligomeric protein that permeabilizes the mitochondria, leading to cell death. Because renegade BAX activation poses a grave risk to the cell, the architecture of BAX must ensure monomeric stability yet simultaneously enable conformational change upon stress signaling. The specific structural features that afford both stability and dynamic flexibility remain ill-defined and represent a critical control point of BAX regulation. Here, we identified a nexus of interactions involving four discrete residues of the BAX core α5 helix that are individually essential to maintaining the structure and latency of monomeric BAX and are collectively required for dimeric assembly. We compared the HDX MS profile of full-length recombinant wild-type BAX in solution with that of the BAX L113A, F114A, Y115A, and F116A single point mutants. In each case, we observed striking, regiospecific consequences of replacing the bulky hydrophobic residue with alanine. We also compared HDX in a construct of α2-α5 for the wt protein as well as mutants. The dual yet distinct roles of these residues reveals the intricacy of BAX conformational regulation and opportunities for therapeutic modulation.
2021-08-26 | PXD024479 | Pride
Project description:BCL-2-associated X protein (BAX) is a promising therapeutic target for activating or restraining apoptosis in diseases of pathologic cell survival or cell death, respectively. In response to cellular stress, BAX transforms from a quiescent cytosolic monomer into a toxic oligomer that permeabilizes the mitochondria, releasing key apoptogenic factors. The mitochondrial lipid trans-2-hexadecenal (t-2-hex) sensitizes BAX activation by covalent derivatization of cysteine 126 (C126). Here, we performed a disulfide tethering screen to discover C126-reactive molecules that modulate BAX activity. We identified covalent BAX inhibitor 1 (CBI1) as a compound that selectively derivatizes BAX at C126 and inhibits BAX activation by the physiologic ligand tBID and point mutagenesis. Biochemical and structural analyses revealed that CBI1 can inhibit BAX by a dual mechanism of action: conformational constraint and competitive blockade of lipidation. Hydrogen deuterium exchange mass spectrometry (HDX MS) showed that CBI1 derivatization of BAX C126 reversed the conformational changes caused by the auto-activating mutant F116A These data inform a pharmacologic strategy for blocking apoptosis in diseases of unwanted cell death by covalent targeting of BAX C126.
2024-01-19 | PXD040917 | Pride