Cross-saturation and transferred cross-saturation experiments

2014 ◽  
Vol 47 (2) ◽  
pp. 143-187 ◽  
Author(s):  
Takumi Ueda ◽  
Koh Takeuchi ◽  
Noritaka Nishida ◽  
Pavlos Stampoulis ◽  
Yutaka Kofuku ◽  
...  
Keyword(s):  
Lipid Bilayers ◽  
Protein Interactions ◽  
Structural Information ◽  
Protein Complexes ◽  
Protein Protein Interactions ◽  
Molecular Weights ◽  
Protein Ligands ◽  
Close Proximity ◽  
Complex Models ◽  
Functional Mechanisms

AbstractStructural analyses of protein–protein interactions are required to reveal their functional mechanisms, and accurate protein–protein complex models, based on experimental results, are the starting points for drug development. In addition, structural information about proteins under physiologically relevant conditions is crucially important for understanding biological events. However, for proteins such as those embedded in lipid bilayers and transiently complexed with their effectors under physiological conditions, structural analyses by conventional methods are generally difficult, due to their large molecular weights and inhomogeneity. We have developed the cross-saturation (CS) method, which is an nuclear magnetic resonance measurement technique for the precise identification of the interfaces of protein–protein complexes. In addition, we have developed an extended version of the CS method, termed transferred cross-saturation (TCS), which enables the identification of the residues of protein ligands in close proximity to huge (>150 kDa) and heterogeneous complexes under fast exchange conditions (>0.1 s−1). Here, we discuss the outline, basic theory, and practical considerations of the CS and TCS methods. In addition, we will review the recent progress in the construction of models of protein–protein complexes, based on CS and TCS experiments, and applications of TCS to in situ analyses of biologically and medically important proteins in physiologically relevant states.

Protein Interaction Domains and Post-Translational Modifications: Structural Features and Drug Discovery Applications

2020 ◽  
Vol 27 (37) ◽  
pp. 6306-6355 ◽  
Author(s):  
Marian Vincenzi ◽  
Flavia Anna Mercurio ◽  
Marilisa Leone
Keyword(s):  
Drug Discovery ◽  
Protein Interaction ◽  
Protein Interactions ◽  
Structural Information ◽  
Protein Complexes ◽  
Structural Features ◽  
Protein Protein Interactions ◽  
Modular Architecture ◽  
Post Translational Modifications ◽  
Interaction Domains

Background:: Many pathways regarding healthy cells and/or linked to diseases onset and progression depend on large assemblies including multi-protein complexes. Protein-protein interactions may occur through a vast array of modules known as protein interaction domains (PIDs). Objective:: This review concerns with PIDs recognizing post-translationally modified peptide sequences and intends to provide the scientific community with state of art knowledge on their 3D structures, binding topologies and potential applications in the drug discovery field. Method:: Several databases, such as the Pfam (Protein family), the SMART (Simple Modular Architecture Research Tool) and the PDB (Protein Data Bank), were searched to look for different domain families and gain structural information on protein complexes in which particular PIDs are involved. Recent literature on PIDs and related drug discovery campaigns was retrieved through Pubmed and analyzed. Results and Conclusion:: PIDs are rather versatile as concerning their binding preferences. Many of them recognize specifically only determined amino acid stretches with post-translational modifications, a few others are able to interact with several post-translationally modified sequences or with unmodified ones. Many PIDs can be linked to different diseases including cancer. The tremendous amount of available structural data led to the structure-based design of several molecules targeting protein-protein interactions mediated by PIDs, including peptides, peptidomimetics and small compounds. More studies are needed to fully role out, among different families, PIDs that can be considered reliable therapeutic targets, however, attacking PIDs rather than catalytic domains of a particular protein may represent a route to obtain selective inhibitors.

scholarly journals Synthesis of two new enrichable and MS-cleavable cross-linkers to define protein–protein interactions by mass spectrometry

2015 ◽  
Vol 13 (17) ◽  
pp. 5030-5037 ◽  
Author(s):  
Anthony M. Burke ◽  
Wynne Kandur ◽  
Eric J. Novitsky ◽  
Robyn M. Kaake ◽  
Clinton Yu ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Protein Interactions ◽  
Structural Information ◽  
Protein Complexes ◽  
Cross Linking ◽  
Protein Protein Interactions ◽  
The Cross

The cross-linking Mass Spectrometry (XL-MS) technique extracts structural information from protein complexes without requiring highly purified samples, crystallinity, or large amounts of material.

scholarly journals Investigation of protein–protein interactions by isotope‒edited Fourier transformed infrared spectroscopy

2004 ◽  
Vol 18 (3) ◽  
pp. 397-406 ◽  
Author(s):  
Tiansheng Li
Keyword(s):  
Ftir Spectroscopy ◽  
Conformational Changes ◽  
Protein Interactions ◽  
Isotope Labeling ◽  
Structural Information ◽  
Protein Complexes ◽  
Secondary Structures ◽  
Receptor Complex ◽  
Protein Protein Interactions

Recent advance in FTIR spectroscopy has shown the usefulness of13C uniform isotope labeling in proteins to study protein–protein interactions.13C uniform isotope labeling can significantly resolve the spectral overlap in the amide I/I′ region in the spectra of protein–protein complexes, and therefore allows more accurate determination of secondary structures of individual protein component in the complex than does the conventional FTIR spectroscopy. Only a limited number of biophysical techniques can be used effectively to obtain structural information of large protein–protein complex in solution. Though X‒ray crystallography and NMR have been used to provide structural information of proteins at atomic resolution, they are limited either by the ability of protein to crystallize or the large molecular weight of protein. Vibrational spectroscopy, including FTIR and Raman spectroscopies, has been extensively employed to investigate secondary structures and conformational dynamics of protein–protein complexes. However, significant spectral overlap in the amide I/Iʹ region in the spectra of protein–protein complexes often hinders the utilization of vibrational spectroscopy in the study of protein–protein complex. In this review, we shall discuss our recent work involving the application of isotope labeled FTIR to the investigation of protein–protein complexes such as cytokine–receptor complexes. One of the examples involves G‒CSF/receptor complex. To determine unambiguously the conformations of G‒CSF and the receptor in the complex, we have prepared uniformly13C/15N isotope labeled G‒CSF to resolve its amide Iʹ band from that of its receptor in the IR spectrum of the complex. Conformational changes and structural stability of individual protein subunit in G‒CSF/receptor complex have then been investigated by using FTIR spectroscopy (Li et al.,Biochemistry29 (1997), 8849–8859). Another example involves BDNF/trkB complex in which13C/15N uniformly labeled BDNF is complexed with its receptor trkB (Li et al.,Biopolymers67(1) (2002), 10–19). Interactions of13C/15N uniformly labeled brain‒derived neurotrophic factor (BDNF) with the extracellular domain of its receptor, trkB, have been investigated by employing FTIR spectroscopy. Conformational changes and structural stability and dynamics of BDNF/trkB complex have been determined unambiguously by FTIR spectroscopy, since amide I/Iʹ bands of13C/15N labeled BDNF are resolved from those of the receptor. Together, those studies have shown that isotope edited FTIR spectroscopy can be successfully applied to the determination of protein secondary structures of protein complexes containing either the same or different types of secondary structures. It was observed that13C/15N uniform labeling also affects significantly the frequency of amide IIʹ band, which may permit the determination of hydrogen–deuterium exchange in individual subunit of protein–protein complexes.

scholarly journals Reliable identification of protein-protein interactions by crosslinking mass spectrometry

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Swantje Lenz ◽  
Ludwig R. Sinn ◽  
Francis J. O’Reilly ◽  
Lutz Fischer ◽  
Fritz Wegner ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Protein Interactions ◽  
Large Scale ◽  
Structural Information ◽  
Protein Complexes ◽  
Interaction Network ◽  
Protein Protein Interactions ◽  
False Discovery Rates ◽  
Large Scale Analysis ◽  
Exit Tunnel

AbstractProtein-protein interactions govern most cellular pathways and processes, and multiple technologies have emerged to systematically map them. Assessing the error of interaction networks has been a challenge. Crosslinking mass spectrometry is currently widening its scope from structural analyses of purified multi-protein complexes towards systems-wide analyses of protein-protein interactions (PPIs). Using a carefully controlled large-scale analysis of Escherichia coli cell lysate, we demonstrate that false-discovery rates (FDR) for PPIs identified by crosslinking mass spectrometry can be reliably estimated. We present an interaction network comprising 590 PPIs at 1% decoy-based PPI-FDR. The structural information included in this network localises the binding site of the hitherto uncharacterised protein YacL to near the DNA exit tunnel on the RNA polymerase.

Mapping of Protein-Protein Interactions: Web-Based Resources for Revealing Interactomes

2019 ◽  
Vol 26 (21) ◽  
pp. 3890-3910 ◽  
Author(s):  
Branislava Gemovic ◽  
Neven Sumonja ◽  
Radoslav Davidovic ◽  
Vladimir Perovic ◽  
Nevena Veljkovic
Keyword(s):  
Drug Discovery ◽  
Protein Interactions ◽  
Protein Complexes ◽  
Experimental Studies ◽  
Protein Protein Interactions ◽  
Web Based ◽  
Prediction Tools ◽  
Physiological Processes ◽  
Modern Drug ◽  
Ppi Prediction

Background: The significant number of protein-protein interactions (PPIs) discovered by harnessing concomitant advances in the fields of sequencing, crystallography, spectrometry and two-hybrid screening suggests astonishing prospects for remodelling drug discovery. The PPI space which includes up to 650 000 entities is a remarkable reservoir of potential therapeutic targets for every human disease. In order to allow modern drug discovery programs to leverage this, we should be able to discern complete PPI maps associated with a specific disorder and corresponding normal physiology. Objective: Here, we will review community available computational programs for predicting PPIs and web-based resources for storing experimentally annotated interactions. Methods: We compared the capacities of prediction tools: iLoops, Struck2Net, HOMCOS, COTH, PrePPI, InterPreTS and PRISM to predict recently discovered protein interactions. Results: We described sequence-based and structure-based PPI prediction tools and addressed their peculiarities. Additionally, since the usefulness of prediction algorithms critically depends on the quality and quantity of the experimental data they are built on; we extensively discussed community resources for protein interactions. We focused on the active and recently updated primary and secondary PPI databases, repositories specialized to the subject or species, as well as databases that include both experimental and predicted PPIs. Conclusion: PPI complexes are the basis of important physiological processes and therefore, possible targets for cell-penetrating ligands. Reliable computational PPI predictions can speed up new target discoveries through prioritization of therapeutically relevant protein–protein complexes for experimental studies.

scholarly journals Mechanism of NanR gene repression and allosteric induction of bacterial sialic acid metabolism

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Christopher R. Horne ◽  
Hariprasad Venugopal ◽  
Santosh Panjikar ◽  
David M. Wood ◽  
Amy Henrickson ◽  
...  
Keyword(s):  
Sialic Acid ◽  
Dna Binding ◽  
Protein Interactions ◽  
Acid Metabolism ◽  
Environmental Changes ◽  
Dna Interaction ◽  
Protein Protein Interactions ◽  
Nutrient Source ◽  
Cryo Electron Microscopy ◽  
Close Proximity

AbstractBacteria respond to environmental changes by inducing transcription of some genes and repressing others. Sialic acids, which coat human cell surfaces, are a nutrient source for pathogenic and commensal bacteria. The Escherichia coli GntR-type transcriptional repressor, NanR, regulates sialic acid metabolism, but the mechanism is unclear. Here, we demonstrate that three NanR dimers bind a (GGTATA)3-repeat operator cooperatively and with high affinity. Single-particle cryo-electron microscopy structures reveal the DNA-binding domain is reorganized to engage DNA, while three dimers assemble in close proximity across the (GGTATA)3-repeat operator. Such an interaction allows cooperative protein-protein interactions between NanR dimers via their N-terminal extensions. The effector, N-acetylneuraminate, binds NanR and attenuates the NanR-DNA interaction. The crystal structure of NanR in complex with N-acetylneuraminate reveals a domain rearrangement upon N-acetylneuraminate binding to lock NanR in a conformation that weakens DNA binding. Our data provide a molecular basis for the regulation of bacterial sialic acid metabolism.

scholarly journals Frequent assembly of chimeric complexes in the protein interaction network of an interspecies yeast hybrid

2020 ◽  
Author(s):  
Rohan Dandage ◽  
Caroline M Berger ◽  
Isabelle Gagnon-Arsenault ◽  
Kyung-Mee Moon ◽  
Richard Greg Stacey ◽  
...  
Keyword(s):  
Protein Interactions ◽  
Molecular Level ◽  
Yeast Species ◽  
Protein Complexes ◽  
Mitochondrial Protein ◽  
Chimeric Protein ◽  
Interaction Network ◽  
Protein Protein Interactions ◽  
Extreme Phenotypes ◽  
Yeast Hybrid

Abstract Hybrids between species often show extreme phenotypes, including some that take place at the molecular level. In this study, we investigated the phenotypes of an interspecies diploid hybrid in terms of protein-protein interactions inferred from protein correlation profiling. We used two yeast species, Saccharomyces cerevisiae and Saccharomyces uvarum, which are interfertile, but yet have proteins diverged enough to be differentiated using mass spectrometry. Most of the protein-protein interactions are similar between hybrid and parents, and are consistent with the assembly of chimeric complexes, which we validated using an orthogonal approach for the prefoldin complex. We also identified instances of altered protein-protein interactions in the hybrid, for instance in complexes related to proteostasis and in mitochondrial protein complexes. Overall, this study uncovers the likely frequent occurrence of chimeric protein complexes with few exceptions, which may result from incompatibilities or imbalances between the parental proteins.

scholarly journals Trifunctional cross-linker for mapping protein-protein interaction networks and comparing protein conformational states

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Dan Tan ◽  
Qiang Li ◽  
Mei-Jun Zhang ◽  
Chao Liu ◽  
Chengying Ma ◽  
...  
Keyword(s):  
Protein Interactions ◽  
Structural Information ◽  
Affinity Purification ◽  
Protein Protein Interactions ◽  
C Elegans ◽  
Protein Protein Interaction ◽  
Lysine Residues ◽  
Spacer Arm ◽  
Cross Linker ◽  
Protein Nucleic Acid

To improve chemical cross-linking of proteins coupled with mass spectrometry (CXMS), we developed a lysine-targeted enrichable cross-linker containing a biotin tag for affinity purification, a chemical cleavage site to separate cross-linked peptides away from biotin after enrichment, and a spacer arm that can be labeled with stable isotopes for quantitation. By locating the flexible proteins on the surface of 70S ribosome, we show that this trifunctional cross-linker is effective at attaining structural information not easily attainable by crystallography and electron microscopy. From a crude Rrp46 immunoprecipitate, it helped identify two direct binding partners of Rrp46 and 15 protein-protein interactions (PPIs) among the co-immunoprecipitated exosome subunits. Applying it to E. coli and C. elegans lysates, we identified 3130 and 893 inter-linked lysine pairs, representing 677 and 121 PPIs. Using a quantitative CXMS workflow we demonstrate that it can reveal changes in the reactivity of lysine residues due to protein-nucleic acid interaction.

scholarly journals Activation and assembly of the NADPH oxidase: a structural perspective

2005 ◽  
Vol 386 (3) ◽  
pp. 401-416 ◽  
Author(s):  
Yvonne GROEMPING ◽  
Katrin RITTINGER
Keyword(s):  
Nadph Oxidase ◽  
Protein Interactions ◽  
Structural Information ◽  
Three Dimensional ◽  
Protein Protein Interactions ◽  
Crucial Component ◽  
Enzyme Subunits ◽  
Membrane Components ◽  
Inhibitory Interactions ◽  
Encompassing Model

The NADPH oxidase of professional phagocytes is a crucial component of the innate immune response due to its fundamental role in the production of reactive oxygen species that act as powerful microbicidal agents. The activity of this multi-protein enzyme is dependent on the regulated assembly of the six enzyme subunits at the membrane where oxygen is reduced to superoxide anions. In the resting state, four of the enzyme subunits are maintained in the cytosol, either through auto-inhibitory interactions or through complex formation with accessory proteins that are not part of the active enzyme complex. Multiple inputs are required to disrupt these inhibitory interactions and allow translocation to the membrane and association with the integral membrane components. Protein interaction modules are key regulators of NADPH oxidase assembly, and the protein–protein interactions mediated via these domains have been the target of numerous studies. Many models have been put forward to describe the intricate network of reversible protein interactions that regulate the activity of this enzyme, but an all-encompassing model has so far been elusive. An important step towards an understanding of the molecular basis of NADPH oxidase assembly and activity has been the recent solution of the three-dimensional structures of some of the oxidase components. We will discuss these structures in the present review and attempt to reconcile some of the conflicting models on the basis of the structural information available.

scholarly journals Mass spectrometry-based cross-linking study shows that the Psb28 protein binds to cytochrome b559 in Photosystem II

2017 ◽  
Vol 114 (9) ◽  
pp. 2224-2229 ◽  
Author(s):  
Daniel A. Weisz ◽  
Haijun Liu ◽  
Hao Zhang ◽  
Sundarapandian Thangapandian ◽  
Emad Tajkhorshid ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Photosystem Ii ◽  
Protein Interactions ◽  
Protein Complexes ◽  
Protein Docking ◽  
Cross Linking ◽  
Protein Protein Interactions ◽  
Cytochrome B559 ◽  
Reaction Center Complex ◽  
Assembly Intermediate

Photosystem II (PSII), a large pigment protein complex, undergoes rapid turnover under natural conditions. During assembly of PSII, oxidative damage to vulnerable assembly intermediate complexes must be prevented. Psb28, the only cytoplasmic extrinsic protein in PSII, protects the RC47 assembly intermediate of PSII and assists its efficient conversion into functional PSII. Its role is particularly important under stress conditions when PSII damage occurs frequently. Psb28 is not found, however, in any PSII crystal structure, and its structural location has remained unknown. In this study, we used chemical cross-linking combined with mass spectrometry to capture the transient interaction of Psb28 with PSII. We detected three cross-links between Psb28 and the α- and β-subunits of cytochrome b559, an essential component of the PSII reaction-center complex. These distance restraints enable us to position Psb28 on the cytosolic surface of PSII directly above cytochrome b559, in close proximity to the QB site. Protein–protein docking results also support Psb28 binding in this region. Determination of the Psb28 binding site and other biochemical evidence allow us to propose a mechanism by which Psb28 exerts its protective effect on the RC47 intermediate. This study also shows that isotope-encoded cross-linking with the “mass tags” selection criteria allows confident identification of more cross-linked peptides in PSII than has been previously reported. This approach thus holds promise to identify other transient protein–protein interactions in membrane protein complexes.

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