Hydrogen-deuterium exchange mass spectrometry is integrated with molecular docking and available crystal structures to investigate the solution-state conformational dynamics of the mitochondrial deubiquitinase USP30, revealing dynamic features not resolved in crystal structures and highlighting the value of HDX-MS for guiding DUB-targeted drug discovery.
Abstract
Abstract Protein conformational heterogeneity presents a major challenge for structure determination and structure-based inhibitor design, particularly for enzymes containing flexible or intrinsically disordered regions. X-ray crystallography and cryo-EM often capture only static conformations and frequently rely on truncated constructs that omit dynamic regions. Here, we integrate hydrogen-deuterium exchange mass spectrometry (HDX-MS) with molecular docking and available crystal structures to investigate the solution-state conformational dynamics of the mitochondrial deubiquitinase USP30. HDX-MS reveals dynamic features not resolved in crystal structures and shows that both covalent and non-covalent inhibitors bind the thumb-palm cleft of the catalytic domain through distinct binding modes. These interactions stabilize different conformational states of the regions surrounding switching (SL1) and blocking (BL1 and BL2) loops, providing mechanistic insight into inhibitor recognition and highlighting the value of HDX-MS for guiding DUB-targeted drug discovery.
A structural database that systematically maps the complete activation trajectories of pharmaceutically relevant targets, encompassing TS, IS, and all connecting conformational ensembles is presented, offering multiple strategic advantages for drug discovery.
This work highlights how distinct inhibitors exploit different conformational states of cKIT and demonstrates the value of integrating structural analyses, biophysical measurements, calculations and molecular simulations to define the mechanism of kinase inhibition.
Irene Cipollone, Carmen Gratteri, C. Talarico et al.· International Journal of Bio...· 0 citations
Whether binding specificity and partner selection in protein-protein interactions (PPIs) can be reliably inferred from static structures or require more dynamic, pathway-resolved energetic analyses remains an open question. To explore this, we focus on the ornithine decarboxylase (ODC)-antizyme isoform 1 (Az1)-antizyme inhibitor (AzIN) system, a well-characterized competitive PPI network that plays a critical role in regulating polyamine homeostasis. By combining extensive all-atom molecular dynamics simulations with biochemical experiments and the development of a new tool, we uncover key dynamic features of the static and recognition pathway interaction. Based on these, we designed novel antizyme isoforms (NAZs). Our analysis, using residue-resolved energetic landscapes, reveals critical determinants of binding specificity and partner selection that static structures alone cannot capture. These insights guide the engineering of NAZs that either directly engage ODC or modulate Az1 availability. This work provides a new perspective, demonstrating that dynamic energetic landscapes, rather than static structures, are key to understanding and modulating competitive protein recognition. Additionally, our DyResEL tool enables broader, more detailed analyses of energetic contributions, offering a versatile approach for exploring PPIs in various biological contexts.
Baolin Guo, Qian Xue, Fan Yang et al.· Journal of Chemical Informat...· 0 citations
Kinases are major drug targets especially in cancer therapy. However, the high degree of conservation of their active sites hinders the development of selective inhibitors, motivating a deeper understanding of kinase conformational ensembles and allosteric communication pathways. Here, we use dynamical network analysis to identify key residues involved in a dynamic allostery between the N- and C-lobes that connects the major functional units of the MAP kinase p38α. By combining NMR spectroscopy, activity assays, and in silico analysis of wildtype protein and mutants in the presence or absence of an active-site inhibitor, we experimentally validate the obtained architecture with respect to global protein motion and long-range allosteric modulation. Notably, the identified network highlights communication pathways across several functional sites, prominently involving the allosteric site, the activation loop, and even the lipid-binding domain with its embedded cryptic pocket in the C-lobe. These findings provide mechanistic insight into p38α allostery and suggest viable opportunities for the rational design of allosteric modulators of MAP kinases.
Suchandra Roy Acharyya, J. Weisner, Rafael C. Bernardi et al.· Nature Communications· 0 citations
Investigating the conformational dynamics of intrinsically disordered proteins (IDPs) is essential to understanding how their structural heterogeneity underlies function and how their dysregulation contributes to diseases. Here, we utilized an MspA nanopore-based approach for studying the conformational dynamics and interactions of IDPs at the single-molecule level. The platform was demonstrated using the intrinsically disordered transactivation domain of tumor suppressor p53 (p53-TAD), one of the important proteins in cancer biology. We showed that MspA can stably capture p53-TAD and resolve up to six distinct current states with frequent interconversions, revealing a rich conformational landscape. The nanopore also detected the effect of a cancer-associated double mutational variant, N29K/N30D. Combining experiments with steered molecular dynamics simulations, we showed that the mutant sampled compact conformational states more frequently than wild type, consistent with previous NMR studies. Importantly, the MspA platform enabled direct monitoring of E3 ligase MDM2 binding to p53-TAD and resolved how this interaction is inhibited by anti-cancer compound epigallocatechin gallate (EGCG). Notably, EGCG stabilizes one of the six states sampled by p53-TAD, providing a mechanistic explanation for its inhibitory effect. Together, these findings demonstrate the promise of the nanopore platform for label-free monitoring of IDP conformational dynamics, modulation, binding and inhibition at single-molecule resolution.
David DeCoeur, Samantha A Schultz, Jianhan Chen et al.· bioRxiv· 0 citations
Determining the higher order structure (HOS) of proteins and protein complexes is central to understanding their functions, dynamics, and interactions. Traditional structural biology approaches, such as X-ray crystallography and nuclear magnetic resonance, provide high-resolution snapshots but often require large amounts of homogeneous samples and may miss dynamic or heterogeneous states. Mass spectrometry (MS) has become an indispensable tool for sensitive and rapid analysis of intact proteins and assemblies under native or near-native conditions. This review discusses the major MS-based strategies for probing HOS. Native mass spectrometry (nMS) preserves non-covalent interactions and exhibits characteristic charge-state distributions that report on folding, while native top-down fragmentation and ion mobility spectrometry provide sequence-specific and conformation-specific information. Hydrogen–deuterium exchange MS measures backbone amide exchange rates to map regions of solvent accessibility, ligand binding, and allosteric regulation in solution. Covalent labeling MS irreversibly modifies solvent-accessible side chains, allowing epitope mapping and detection of subtle conformational changes, while fast photochemical oxidation of proteins offers microsecond snapshots of transient structures. Chemical cross-linking MS applies bifunctional reagents to capture proximity between residues or subunits, providing distance restraints for integrative modeling and proteome-wide interaction mapping. We outline recent advances in instrumentation, software, labeling chemistry and in-cell techniques across these modalities, and we illustrate their applications to characterizing membrane proteins, large assemblies, therapeutic antibodies, intrinsically disordered proteins, and protein–ligand complexes. Together, these tools offer complementary insights into HOS that are reshaping structural biology, biopharmaceutical development and mechanistic studies.
Dulakshi Herath, Kaitlyn N. Walls, Ashlyn N. Dollar et al.· In Analysis· 0 citations
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