scholarly journals Flexible regions in the molecular architecture of Human fibrin clots structurally resolved by XL-MS and integrative structural modeling

2019 ◽  
Author(s):  
Oleg Klykov ◽  
Carmen van der Zwaan ◽  
Albert J.R. Heck ◽  
Alexander B. Meijer ◽  
Richard A. Scheltema
Keyword(s):  
Molecular Mechanisms ◽  
Interaction Network ◽  
Structural Modeling ◽  
Structural Features ◽  
Heparin Binding ◽  
Molecular Architecture ◽  
Novel Treatments ◽  
Structural Details ◽  
Heparin Binding Domain ◽  
Fibrin Clots

AbstractUpon activation, fibrinogen forms large fibrin biopolymers that coalesce into clots that assist in wound healing. Limited insights into their molecular architecture, due to the sheer size and insoluble character of fibrin clots, have however restricted our ability to develop novel treatments for clotting diseases. The so far resolved disparate structural details did provide insights into linear elongation; however, molecular details like the C-terminal domain of theα-chain, the heparin-binding domain on theβ-chain, and others involved in lateral aggregation are lacking. To illuminate these dark areas, we applied crosslinking mass spectrometry (XL-MS) to obtain biochemical evidence in the form of over 300 distance constraints and combined this with structural modeling. These restraints additionally define the interaction network of the clots and e.g. provide molecular details for the interaction with Human Serum Albumin (HSA). We were able to construct the models of fibrinogenα(excluding two highly flexible regions) andβ, confirm these models with known structural arrangements and map how the structure laterally aggregates to form intricate lattices together with fibrinogenγ. We validate the final model by mapping mutations leading to impaired clot formation. From a list of 22 mutations, we uncovered structural features for all, including a crucial role forβArg’196 in lateral aggregation. The resulting model will be invaluable for research on dysfibrinogenemia and amyloidosis, as it provides insights into the molecular mechanisms of thrombosis and bleeding disorders related to fibrinogen variants. The structure is provided in the PDB-DEV repository.

scholarly journals Missing regions within the molecular architecture of human fibrin clots structurally resolved by XL-MS and integrative structural modeling

2020 ◽  
Vol 117 (4) ◽  
pp. 1976-1987 ◽  
Author(s):  
Oleg Klykov ◽  
Carmen van der Zwaan ◽  
Albert J. R. Heck ◽  
Alexander B. Meijer ◽  
Richard A. Scheltema
Keyword(s):  
Molecular Mechanisms ◽  
Interaction Network ◽  
Structural Modeling ◽  
Structural Features ◽  
Heparin Binding ◽  
Molecular Architecture ◽  
Novel Treatments ◽  
Α Chain ◽  
Β Chain ◽  
Fibrin Clots

Upon activation, fibrinogen forms large fibrin biopolymers that coalesce into clots which assist in wound healing. Limited insights into their molecular architecture, due to the sheer size and the insoluble character of fibrin clots, have restricted our ability to develop novel treatments for clotting diseases. The, so far resolved, disparate structural details have provided insights into linear elongation; however, molecular details like the C-terminal domain of the α-chain, the heparin-binding domain on the β-chain, and other functional domains remain elusive. To illuminate these dark areas, we applied cross-linking mass spectrometry (XL-MS) to obtain biochemical evidence in the form of over 300 distance constraints and combined this with structural modeling. These restraints additionally define the interaction network of the clots and provide molecular details for the interaction with human serum albumin (HSA). We were able to construct the structural models of the fibrinogen α-chain (excluding two highly flexible regions) and the N termini of the β-chain, confirm these models with known structural arrangements, and map how the structure laterally aggregates to form intricate lattices together with the γ-chain. We validate the final model by mapping mutations leading to impaired clot formation. From a list of 22 mutations, we uncovered structural features for all, including a crucial role for βArg’169 (UniProt: 196) in lateral aggregation. The resulting model can potentially serve for research on dysfibrinogenemia and amyloidosis as it provides insights into the molecular mechanisms of thrombosis and bleeding disorders related to fibrinogen variants. The structure is provided in the PDB-DEV repository (PDBDEV_00000030).

scholarly journals Identification of key regulators in parathyroid adenoma using an integrative gene network analysis

2020 ◽  
Vol 16 (11) ◽  
pp. 910-922
Author(s):  
Nikhat Imam ◽  
Keyword(s):  
Gene Expression ◽  
Parathyroid Adenoma ◽  
Molecular Mechanisms ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Interaction Network ◽  
Gene Interaction ◽  
Structural Features ◽  
Gene Interaction Network ◽  
Parathyroid Adenomas

Parathyroid adenoma (PA) is marked by a certain benign outgrowth in the surface of parathyroid glands. The transcriptome analysis of parathyroid adenomas can provide a deep insight into actively expressed genes and transcripts. Hence, we analyzed and compared the gene expression profiles of parathyroid adenomas and healthy parathyroid gland tissues from database name. We identified a total of 280 differentially expressed genes (196 up-regulated, 84 down-regulated), which are involved in a wide array of biological processes. We further constructed a gene interaction network and analyzed its topological properties to know the network structure and its hidden mechanism. This will help to understand the molecular mechanisms underlying parathyroid adenoma development. We thus identified 13 key regulators (PRPF19, SMC3, POSTN, SNIP1, EBF1, MEIS2, PAX9, SCUBE2, WNT4, ARHGAP10, DOCK5, CAV1 and VSIR), which are deep-rooted from top to bottom in the gene interaction network forming a backbone for the network. The structural features of the network are probably maintained by crosstalk between important genes within the network along with associated functional modules. Thus, gene-expression profiling and network approach could be used to provide an independent platform to glen insights from available clinical data.

Study of the Molecular Architecture of Keratin Filaments by Electron Microscopy

1982 ◽  
Vol 40 ◽  
pp. 118-119
Author(s):  
U. Aebi ◽  
P. Rew ◽  
T.-T. Sun
Keyword(s):  
Electron Microscopy ◽  
Structural Organization ◽  
Cell Types ◽  
Structural Features ◽  
Molecular Architecture ◽  
The Past ◽  
Keratin Filaments ◽  
Different Types ◽  
10 Nm Filaments ◽  
Different Cell Types

Various types of intermediate-sized (10-nm) filaments have been found and described in many different cell types during the past few years. Despite the differences in the chemical composition among the different types of filaments, they all yield common structural features: they are usually up to several microns long and have a diameter of 7 to 10 nm; there is evidence that they are made of several 2 to 3.5 nm wide protofilaments which are helically wound around each other; the secondary structure of the polypeptides constituting the filaments is rich in ∞-helix. However a detailed description of their structural organization is lacking to date.

Lighting a path: genetic studies pinpoint neurodevelopmental mechanisms in autism and related disorders

2012 ◽  
Vol 14 (3) ◽  
pp. 239-252
Keyword(s):  
Molecular Mechanisms ◽  
Protein Localization ◽  
Regulation Of Gene Expression ◽  
Neuronal Cell ◽  
Mrna Splicing ◽  
Genetic Mutations ◽  
Scaffolding Proteins ◽  
Molecular Processes ◽  
Genetic Studies ◽  
Novel Treatments

In this review, we outline critical molecular processes that have been implicated by discovery of genetic mutations in autism. These mechanisms need to be mapped onto the neurodevelopment step(s) gone awry that may be associated with cause in autism. Molecular mechanisms include: (i) regulation of gene expression; (ii) pre-mRNA splicing; (iii) protein localization, translation, and turnover; (iv) synaptic transmission; (v) cell signaling; (vi) the functions of cytoskeletal and scaffolding proteins; and (vii) the function of neuronal cell adhesion molecules. While the molecular mechanisms appear broad, they may converge on only one of a few steps during neurodevelopment that perturbs the structure, function, and/or plasticity of neuronal circuitry. While there are many genetic mutations involved, novel treatments may need to target only one of few developmental mechanisms.

Identifying Alzheimer’s Disease-related miRNA Based on Semi-clustering

2019 ◽  
Vol 19 (4) ◽  
pp. 216-223 ◽  
Author(s):  
Tianyi Zhao ◽  
Donghua Wang ◽  
Yang Hu ◽  
Ningyi Zhang ◽  
Tianyi Zang ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Drug Targets ◽  
Molecular Mechanisms ◽  
Feature Vector ◽  
Mirna Gene ◽  
Interaction Network ◽  
Gene Interaction ◽  
Proteinprotein Interaction ◽  
Synaptic Structures

Background: More and more scholars are trying to use it as a specific biomarker for Alzheimer’s Disease (AD) and mild cognitive impairment (MCI). Multiple studies have indicated that miRNAs are associated with poor axonal growth and loss of synaptic structures, both of which are early events in AD. The overall loss of miRNA may be associated with aging, increasing the incidence of AD, and may also be involved in the disease through some specific molecular mechanisms. Objective: Identifying Alzheimer’s disease-related miRNA can help us find new drug targets, early diagnosis. Materials and Methods: We used genes as a bridge to connect AD and miRNAs. Firstly, proteinprotein interaction network is used to find more AD-related genes by known AD-related genes. Then, each miRNA’s correlation with these genes is obtained by miRNA-gene interaction. Finally, each miRNA could get a feature vector representing its correlation with AD. Unlike other studies, we do not generate negative samples randomly with using classification method to identify AD-related miRNAs. Here we use a semi-clustering method ‘one-class SVM’. AD-related miRNAs are considered as outliers and our aim is to identify the miRNAs that are similar to known AD-related miRNAs (outliers). Results and Conclusion: We identified 257 novel AD-related miRNAs and compare our method with SVM which is applied by generating negative samples. The AUC of our method is much higher than SVM and we did case studies to prove that our results are reliable.

scholarly journals Biophysical characterization of melanoma cell phenotype markers during metastatic progression

2021 ◽  
Author(s):  
Anna Sobiepanek ◽  
Alessio Paone ◽  
Francesca Cutruzzolà ◽  
Tomasz Kobiela
Keyword(s):  
Molecular Mechanisms ◽  
Cell Metabolism ◽  
Structural Features ◽  
Protein Glycosylation ◽  
Cell Phenotype ◽  
Metastatic Progression ◽  
Label Free ◽  
Serine Threonine Kinase ◽  
Biophysical Characterization ◽  
Viscoelastic Parameters

AbstractMelanoma is the most fatal form of skin cancer, with increasing prevalence worldwide. The most common melanoma genetic driver is mutation of the proto-oncogene serine/threonine kinase BRAF; thus, the inhibition of its MAP kinase pathway by specific inhibitors is a commonly applied therapy. However, many patients are resistant, or develop resistance to this type of monotherapy, and therefore combined therapies which target other signaling pathways through various molecular mechanisms are required. A possible strategy may involve targeting cellular energy metabolism, which has been recognized as crucial for cancer development and progression and which connects through glycolysis to cell surface glycan biosynthetic pathways. Protein glycosylation is a hallmark of more than 50% of the human proteome and it has been recognized that altered glycosylation occurs during the metastatic progression of melanoma cells which, in turn facilitates their migration. This review provides a description of recent advances in the search for factors able to remodel cell metabolism between glycolysis and oxidative phosphorylation, and of changes in specific markers and in the biophysical properties of cells during melanoma development from a nevus to metastasis. This development is accompanied by changes in the expression of surface glycans, with corresponding changes in ligand-receptor affinity, giving rise to structural features and viscoelastic parameters particularly well suited to study by label-free biophysical methods.

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.

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