scholarly journals Four-dimensional NOE-NOE spectroscopy of SARS-CoV-2 Main Protease to facilitate resonance assignment and structural analysis

2021 ◽  
Vol 2 (1) ◽  
pp. 129-138
Author(s):  
Angus J. Robertson ◽  
Jinfa Ying ◽  
Ad Bax
Keyword(s):  
Resonance Assignment ◽  
Structural Information ◽  
Resonance Assignments ◽  
Structural Features ◽  
Dipolar Relaxation ◽  
X Ray Crystallography ◽  
Main Protease ◽  
Back Exchange ◽  
4D Noesy ◽  
Exchange Broadening

Abstract. Resonance assignment and structural studies of larger proteins by nuclear magnetic resonance (NMR) can be challenging when exchange broadening, multiple stable conformations, and 1H back-exchange of the fully deuterated chain pose problems. These difficulties arise for the SARS-CoV-2 Main Protease, a homodimer of 2 × 306 residues. We demonstrate that the combination of four-dimensional (4D) TROSY-NOESY-TROSY spectroscopy and 4D NOESY-NOESY-TROSY spectroscopy provides an effective tool for delineating the 1H–1H dipolar relaxation network. In combination with detailed structural information obtained from prior X-ray crystallography work, such data are particularly useful for extending and validating resonance assignments as well as for probing structural features.

scholarly journals Four-dimensional NOE-NOE spectroscopy of SARS-CoV-2 Main Protease to facilitate resonance assignment and structural analysis

2021 ◽  
Author(s):  
Angus J. Robertson ◽  
Jinfa Ying ◽  
Ad Bax
Keyword(s):  
Resonance Assignment ◽  
Structural Information ◽  
Structural Features ◽  
Structural Studies ◽  
Dipolar Relaxation ◽  
X Ray ◽  
X Ray Crystallography ◽  
Main Protease ◽  
4D Noesy ◽  
Exchange Broadening

Abstract. Resonance assignment and structural studies of larger proteins by NMR can be challenging when exchange broadening, multiple stable conformations, and back-exchanging the fully deuterated chain pose problems. These difficulties arise for the SARS-CoV-2 Main Protease, a homodimer of 2×306 residues. We demonstrate that the combination of four-dimensional (4D) TROSY-NOESY-TROSY spectroscopy and 4D NOESY-NOESY-TROSY spectroscopy provides an effective tool for delineating the 1H-1H dipolar relaxation network. In combination with detailed structural information obtained from prior X-ray crystallography work, such data are particularly useful for extending and validating resonances assignments, as well as for probing structural features.

scholarly journals Structural basis of the heterodimerization of the MST and RASSF SARAH domains in the Hippo signalling pathway

2014 ◽  
Vol 70 (7) ◽  
pp. 1944-1953 ◽  
Author(s):  
Eunha Hwang ◽  
Hae-Kap Cheong ◽  
Ameeq Ul Mushtaq ◽  
Hye-Yeon Kim ◽  
Kwon Joo Yeo ◽  
...  
Keyword(s):  
Structural Information ◽  
Critical Role ◽  
Three Dimensional ◽  
Helical Structure ◽  
Structural Features ◽  
Signalling Pathway ◽  
Structural Basis ◽  
X Ray Crystallography ◽  
Hippo Signalling

Despite recent progress in research on the Hippo signalling pathway, the structural information available in this area is extremely limited. Intriguingly, the homodimeric and heterodimeric interactions of mammalian sterile 20-like (MST) kinases through the so-called `SARAH' (SAV/RASSF/HPO) domains play a critical role in cellular homeostasis, dictating the fate of the cell regarding cell proliferation or apoptosis. To understand the mechanism of the heterodimerization of SARAH domains, the three-dimensional structures of an MST1–RASSF5 SARAH heterodimer and an MST2 SARAH homodimer were determined by X-ray crystallography and were analysed together with that previously determined for the MST1 SARAH homodimer. While the structure of the MST2 homodimer resembled that of the MST1 homodimer, the MST1–RASSF5 heterodimer showed distinct structural features. Firstly, the six N-terminal residues (Asp432–Lys437), which correspond to the short N-terminal 310-helix h1 kinked from the h2 helix in the MST1 homodimer, were disordered. Furthermore, the MST1 SARAH domain in the MST1–RASSF5 complex showed a longer helical structure (Ser438–Lys480) than that in the MST1 homodimer (Val441–Lys480). Moreover, extensive polar and nonpolar contacts in the MST1–RASSF5 SARAH domain were identified which strengthen the interactions in the heterodimer in comparison to the interactions in the homodimer. Denaturation experiments performed using urea also indicated that the MST–RASSF heterodimers are substantially more stable than the MST homodimers. These findings provide structural insights into the role of the MST1–RASSF5 SARAH domain in apoptosis signalling.

scholarly journals A novel conformational state for SARS-CoV-2 main protease

2021 ◽  
Author(s):  
Emanuele Fornasier ◽  
Maria Ludovica Macchia ◽  
Gabriele Giachin ◽  
Alice Sosic ◽  
Matteo Pavan ◽  
...  
Keyword(s):  
Structural Information ◽  
Chemical Space ◽  
Structural Features ◽  
Conformational State ◽  
Conformational Space ◽  
Genome Replication ◽  
Binding Region ◽  
Main Protease ◽  
Promising Target ◽  
Viral Genome Replication

AbstractThe SARS-CoV-2 main protease (Mpro) has a pivotal role in mediating viral genome replication and transcription of coronavirus, making it a promising target for drugs against Covid-19 pandemic. Here we present a crystal structure of Mpro disclosing new structural features of key regions of the enzyme. We show that the oxyanion loop, involved in substrate recognition and enzymatic activity, can adopt a new conformation, which is stable and significantly different from the known ones. In this new state the S1 subsite of the substrate binding region is completely reshaped and a new cavity near the S2’ subsite is created. This new structural information expands the knowledge of the conformational space available to Mpro, paving the way for the design of novel classes of inhibitors specifically designed to target this unprecedented binding site conformation, thus enlarging the chemical space for urgent antiviral drugs against Covid-19 pandemic.

Measurement and Reduction of Radiation Damage in Frozen Hydrated Crystalline Specimens

1978 ◽  
Vol 36 (3) ◽  
pp. 70-77 ◽  
Author(s):  
R.M. Glaeser ◽  
S.B. Hayward
Keyword(s):  
Diffraction Pattern ◽  
Structural Information ◽  
Structural Disorder ◽  
Structural Features ◽  
Biological Macromolecules ◽  
Diffraction Intensity ◽  
Object Structure ◽  
Specimen Material ◽  
Unit Cells ◽  
Identical Unit

Highly ordered or crystalline biological macromolecules become severely damaged and structurally disordered after a brief electron exposure. Evidence that damage and structural disorder are occurring is clearly given by the fading and eventual disappearance of the specimen's electron diffraction pattern. The fading and disappearance of sharp diffraction spots implies a corresponding disappearance of periodic structural features in the specimen. By the same token, there is a oneto- one correspondence between the disappearance of the crystalline diffraction pattern and the disappearance of reproducible structural information that can be observed in the images of identical unit cells of the object structure. The electron exposures that result in a significant decrease in the diffraction intensity will depend somewhat upon the resolution (Bragg spacing) involved, and can vary considerably with the chemical makeup and composition of the specimen material.

HAZARD: An Expert System for Risk Assessment of Environmental Chemicals

1987 ◽  
Vol 26 (01) ◽  
pp. 13-23 ◽  
Author(s):  
H. W. Gottinger
Keyword(s):  
Expert System ◽  
Structural Information ◽  
Chemical Carcinogenesis ◽  
Structural Features ◽  
Environmental Chemicals ◽  
Chemical Carcinogens ◽  
Carcinogenic Activity ◽  
Current State ◽  
Structure Activity ◽  
Carcinogenic Potential

AbstractThe purpose of this paper is to report on an expert system in design that screens for potential hazards from environmental chemicals on the basis of structure-activity relationships in the study of chemical carcinogenesis, particularly with respect to analyzing the current state of known structural information about chemical carcinogens and predicting the possible carcinogenicity of untested chemicals. The structure-activity tree serves as an index of known chemical structure features associated with carcinogenic activity. The basic units of the tree are the principal recognized classes of chemical carcinogens that are subdivided into subclasses known as nodes according to specific structural features that may reflect differences in carcinogenic potential among chemicals in the class. An analysis of a computerized data base of known carcinogens (knowledge base) is proposed using the structure-activity tree in order to test the validity of the tree as a classification scheme (inference engine).

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.

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.

A Systematic Review on Popularity, Application and Characteristics of Protein Secondary Structure Prediction Tools

2019 ◽  
Vol 16 (2) ◽  
pp. 159-172 ◽  
Author(s):  
Elaheh Kashani-Amin ◽  
Ozra Tabatabaei-Malazy ◽  
Amirhossein Sakhteman ◽  
Bagher Larijani ◽  
Azadeh Ebrahim-Habibi
Keyword(s):  
Systematic Review ◽  
Secondary Structure ◽  
Structure Prediction ◽  
Web Of Science ◽  
Secondary Structure Prediction ◽  
Structural Information ◽  
Protein Secondary Structure ◽  
Structural Features ◽  
Prediction Tools ◽  
Insight Into

Background: Prediction of proteins’ secondary structure is one of the major steps in the generation of homology models. These models provide structural information which is used to design suitable ligands for potential medicinal targets. However, selecting a proper tool between multiple Secondary Structure Prediction (SSP) options is challenging. The current study is an insight into currently favored methods and tools, within various contexts. Objective: A systematic review was performed for a comprehensive access to recent (2013-2016) studies which used or recommended protein SSP tools. Methods: Three databases, Web of Science, PubMed and Scopus were systematically searched and 99 out of the 209 studies were finally found eligible to extract data. Results: Four categories of applications for 59 retrieved SSP tools were: (I) prediction of structural features of a given sequence, (II) evaluation of a method, (III) providing input for a new SSP method and (IV) integrating an SSP tool as a component for a program. PSIPRED was found to be the most popular tool in all four categories. JPred and tools utilizing PHD (Profile network from HeiDelberg) method occupied second and third places of popularity in categories I and II. JPred was only found in the two first categories, while PHD was present in three fields. Conclusion: This study provides a comprehensive insight into the recent usage of SSP tools which could be helpful for selecting a proper tool.

scholarly journals The dimer-monomer equilibrium of SARS-CoV-2 main protease is affected by small molecule inhibitors

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Lucia Silvestrini ◽  
Norhan Belhaj ◽  
Lucia Comez ◽  
Yuri Gerelli ◽  
Antonino Lauria ◽  
...  
Keyword(s):  
Enzymatic Activity ◽  
Dissociation Constant ◽  
Molecular Mechanisms ◽  
Antiviral Drug ◽  
Structural Features ◽  
Experimental Information ◽  
Detailed Knowledge ◽  
Main Protease ◽  
Equilibrium Dissociation ◽  
Drug Leads

AbstractThe maturation of coronavirus SARS-CoV-2, which is the etiological agent at the origin of the COVID-19 pandemic, requires a main protease Mpro to cleave the virus-encoded polyproteins. Despite a wealth of experimental information already available, there is wide disagreement about the Mpro monomer-dimer equilibrium dissociation constant. Since the functional unit of Mpro is a homodimer, the detailed knowledge of the thermodynamics of this equilibrium is a key piece of information for possible therapeutic intervention, with small molecules interfering with dimerization being potential broad-spectrum antiviral drug leads. In the present study, we exploit Small Angle X-ray Scattering (SAXS) to investigate the structural features of SARS-CoV-2 Mpro in solution as a function of protein concentration and temperature. A detailed thermodynamic picture of the monomer-dimer equilibrium is derived, together with the temperature-dependent value of the dissociation constant. SAXS is also used to study how the Mpro dissociation process is affected by small inhibitors selected by virtual screening. We find that these inhibitors affect dimerization and enzymatic activity to a different extent and sometimes in an opposite way, likely due to the different molecular mechanisms underlying the two processes. The Mpro residues that emerge as key to optimize both dissociation and enzymatic activity inhibition are discussed.

scholarly journals Computational Modeling to Explain Why 5,5-Diarylpentadienamides are TRPV1 Antagonists

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1765
Author(s):  
Julio Caballero
Keyword(s):  
Transient Receptor Potential ◽  
Structural Information ◽  
Chemical Activation ◽  
Receptor Potential ◽  
Quantitative Structure Activity Relationship ◽  
Structural Features ◽  
Transient Receptor Potential Vanilloid ◽  
Protein Residues ◽  
Topological Features ◽  
Transient Receptor

Several years ago, the crystallographic structures of the transient receptor potential vanilloid 1 (TRPV1) in the presence of agonists and antagonists were reported, providing structural information about its chemical activation and inactivation. TRPV1’s activation increases the transport of calcium and sodium ions, leading to the excitation of sensory neurons and the perception of pain. On the other hand, its antagonistic inactivation has been explored to design analgesic drugs. The interactions between the antagonists 5,5-diarylpentadienamides (DPDAs) and TRPV1 were studied here to explain why they inactivate TRPV1. The present work identified the structural features of TRPV1–DPDA complexes, starting with a consideration of the orientations of the ligands inside the TRPV1 binding site by using molecular docking. After this, a chemometrics analysis was performed (i) to compare the orientations of the antagonists (by using LigRMSD), (ii) to describe the recurrent interactions between the protein residues and ligand groups in the complexes (by using interaction fingerprints), and (iii) to describe the relationship between topological features of the ligands and their differential antagonistic activities (by using a quantitative structure–activity relationship (QSAR) with 2D autocorrelation descriptors). The interactions between the DPDA groups and the residues Y511, S512, T550, R557, and E570 (with a recognized role in the binding of classic ligands), and the occupancy of isoquinoline or 3-hydroxy-3,4-dihydroquinolin-2(1H)-one groups of the DPDAs in the vanilloid pocket of TRPV1 were clearly described. Based on the results, the structural features that explain why DPDAs inactivate TRPV1 were clearly exposed. These features can be considered for the design of novel TRPV1 antagonists.

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