scholarly journals Snails In Silico: A Review of Computational Studies on the Conopeptides

Marine Drugs ◽  
2019 ◽  
Vol 17 (3) ◽  
pp. 145 ◽  
Author(s):  
Rachael Mansbach ◽  
Timothy Travers ◽  
Benjamin McMahon ◽  
Jeanne Fair ◽  
S. Gnanakaran

Marine cone snails are carnivorous gastropods that use peptide toxins called conopeptides both as a defense mechanism and as a means to immobilize and kill their prey. These peptide toxins exhibit a large chemical diversity that enables exquisite specificity and potency for target receptor proteins. This diversity arises in terms of variations both in amino acid sequence and length, and in posttranslational modifications, particularly the formation of multiple disulfide linkages. Most of the functionally characterized conopeptides target ion channels of animal nervous systems, which has led to research on their therapeutic applications. Many facets of the underlying molecular mechanisms responsible for the specificity and virulence of conopeptides, however, remain poorly understood. In this review, we will explore the chemical diversity of conopeptides from a computational perspective. First, we discuss current approaches used for classifying conopeptides. Next, we review different computational strategies that have been applied to understanding and predicting their structure and function, from machine learning techniques for predictive classification to docking studies and molecular dynamics simulations for molecular-level understanding. We then review recent novel computational approaches for rapid high-throughput screening and chemical design of conopeptides for particular applications. We close with an assessment of the state of the field, emphasizing important questions for future lines of inquiry.


Author(s):  
Nicholas J. Mosey ◽  
Martin H. Mu¨ser ◽  
Tom K. Woo

Wear limits the lifespan of many mechanical devices with moving parts. To reduce wear, lubricants are frequently enriched with additives that form protective pads on rubbing surfaces. With first-principles molecular dynamics simulations of pads derived from commercial additives, namely zinc-phosphates, we unravel the molecular origin of how anti-wear pads can form and function. These effects originate from pressure-induced changes in the coordination number of atoms acting as cross-linking agents, in this case zinc, to form chemically connected networks. The proposed mechanism explains a diverse body of experiments and promises to prove useful in the rational design of anti-wear additives that operate on a wider range of surface materials with reduced environmental side-effects.



2006 ◽  
Vol 173 (6) ◽  
pp. 833-837 ◽  
Author(s):  
Gerben Vader ◽  
René H. Medema ◽  
Susanne M.A. Lens

During mitosis, the chromosomal passenger complex (CPC) orchestrates highly different processes, such as chromosome alignment, histone modification, and cytokinesis. Proper and timely localization of this complex is the key to precise control over the enzymatic core of the CPC, the Aurora-B kinase. We discuss the molecular mechanisms by which the CPC members direct the dynamic localization of the complex throughout cell division. Also, we summarize posttranslational modifications that occur on the CPC and discuss their roles in regulating localization and function of this mitotic complex.



2016 ◽  
Vol 113 (39) ◽  
pp. 10938-10943 ◽  
Author(s):  
Stella K. Hur ◽  
Andrea Freschi ◽  
Folami Ideraabdullah ◽  
Joanne L. Thorvaldsen ◽  
Lacey J. Luense ◽  
...  

Genomic imprinting affects a subset of genes in mammals, such that they are expressed in a monoallelic, parent-of-origin–specific manner. These genes are regulated by imprinting control regions (ICRs), cis-regulatory elements that exhibit allele-specific differential DNA methylation. Although genomic imprinting is conserved in mammals, ICRs are genetically divergent across species. This raises the fundamental question of whether the ICR plays a species-specific role in regulating imprinting at a given locus. We addressed this question at the H19/insulin-like growth factor 2 (Igf2) imprinted locus, the misregulation of which is associated with the human imprinting disorders Beckwith–Wiedemann syndrome (BWS) and Silver–Russell syndrome (SRS). We generated a knock-in mouse in which the endogenous H19/Igf2 ICR (mIC1) is replaced by the orthologous human ICR (hIC1) sequence, designated H19hIC1. We show that hIC1 can functionally replace mIC1 on the maternal allele. In contrast, paternally transmitted hIC1 leads to growth restriction, abnormal hIC1 methylation, and loss of H19 and Igf2 imprinted expression. Imprint establishment at hIC1 is impaired in the male germ line, which is associated with an abnormal composition of histone posttranslational modifications compared with mIC1. Overall, this study reveals evolutionarily divergent paternal imprinting at IC1 between mice and humans. The conserved maternal imprinting mechanism and function at IC1 demonstrates the possibility of modeling maternal transmission of hIC1 mutations associated with BWS in mice. In addition, we propose that further analyses in the paternal knock-in H19+/hIC1 mice will elucidate the molecular mechanisms that may underlie SRS.



Biomedicines ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 1702
Author(s):  
Xinfang Yu ◽  
Wei Li ◽  
Ken H. Young ◽  
Yong Li

Programmed death-ligand 1 (PD-L1) is one of the most classic immune checkpoint molecules. Cancer cells express PD-L1 to inhibit the activity of effector T cells’ cytotoxicity through programmed death 1 (PD-1) engagement in exposure to inflammatory cytokines. PD-L1 expression levels on cancer cells might affect the clinical response to anti-PD-1/PD-L1 therapies. Hence, understanding molecular mechanisms for regulating PD-L1 expression is essential for improving the clinical response rate and efficacy of PD-1/PD-L1 blockade. Posttranslational modifications (PTMs), including phosphorylation, glycosylation, ubiquitination, and acetylation, regulate PD-L1 stability, cellular translocation, and interaction with its receptor. A coordinated positive and negative regulation via PTMs is required to ensure the balance and function of the PD-L1 protein. In this review, we primarily focus on the roles of PTMs in PD-L1 expression, trafficking, and antitumor immune response. We also discuss the implication of PTMs in anti-PD-1/PD-L1 therapies.



2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
Michala Kolarova ◽  
Francisco García-Sierra ◽  
Ales Bartos ◽  
Jan Ricny ◽  
Daniela Ripova

Alzheimer's disease (AD) is the most common type of dementia. In connection with the global trend of prolonging human life and the increasing number of elderly in the population, the AD becomes one of the most serious health and socioeconomic problems of the present. Tau protein promotes assembly and stabilizes microtubules, which contributes to the proper function of neuron. Alterations in the amount or the structure of tau protein can affect its role as a stabilizer of microtubules as well as some of the processes in which it is implicated. The molecular mechanisms governing tau aggregation are mainly represented by several posttranslational modifications that alter its structure and conformational state. Hence, abnormal phosphorylation and truncation of tau protein have gained attention as key mechanisms that become tau protein in a pathological entity. Evidences about the clinicopathological significance of phosphorylated and truncated tau have been documented during the progression of AD as well as their capacity to exert cytotoxicity when expressed in cell and animal models. This paper describes the normal structure and function of tau protein and its major alterations during its pathological aggregation in AD.



Planta Medica ◽  
2016 ◽  
Vol 81 (S 01) ◽  
pp. S1-S381
Author(s):  
LS Espindola ◽  
RG Dusi ◽  
KR Gustafson ◽  
J McMahon ◽  
JA Beutler


2018 ◽  
Author(s):  
Stacy A. Malaker ◽  
Kayvon Pedram ◽  
Michael J. Ferracane ◽  
Elliot C. Woods ◽  
Jessica Kramer ◽  
...  

<div> <div> <div> <p>Mucins are a class of highly O-glycosylated proteins that are ubiquitously expressed on cellular surfaces and are important for human health, especially in the context of carcinomas. However, the molecular mechanisms by which aberrant mucin structures lead to tumor progression and immune evasion have been slow to come to light, in part because methods for selective mucin degradation are lacking. Here we employ high resolution mass spectrometry, polymer synthesis, and computational peptide docking to demonstrate that a bacterial protease, called StcE, cleaves mucin domains by recognizing a discrete peptide-, glycan-, and secondary structure- based motif. We exploited StcE’s unique properties to map glycosylation sites and structures of purified and recombinant human mucins by mass spectrometry. As well, we found that StcE will digest cancer-associated mucins from cultured cells and from ovarian cancer patient-derived ascites fluid. Finally, using StcE we discovered that Siglec-7, a glyco-immune checkpoint receptor, specifically binds sialomucins as biological ligands, whereas the related Siglec-9 receptor does not. Mucin-specific proteolysis, as exemplified by StcE, is therefore a powerful tool for the study of glycoprotein structure and function and for deorphanizing mucin-binding receptors. </p> </div> </div> </div>



2020 ◽  
Vol 22 (9) ◽  
pp. 635-648 ◽  
Author(s):  
Korosh Mashayekh ◽  
Shahrzad Sharifi ◽  
Tahereh Damghani ◽  
Maryam Elyasi ◽  
Mohammad S. Avestan ◽  
...  

Background: c-Met kinase plays a critical role in a myriad of human cancers, and a massive scientific work was devoted to design more potent inhibitors. Objective: In this study, 16 molecular dynamics simulations of different complexes of potent c-Met inhibitors with U-shaped binding mode were carried out regarding the dynamic ensembles to design novel potent inhibitors. Methods: A cluster analysis was performed, and the most representative frame of each complex was subjected to the structure-based pharmacophore screening. The GOLD docking program investigated the interaction energy and pattern of output hits from the virtual screening. The most promising hits with the highest scoring values that showed critical interactions with c-Met were presented for ADME/Tox analysis. Results: The screening yielded 45,324 hits that all of them were subjected to the docking studies and 10 of them with the highest-scoring values having diverse structures were presented for ADME/Tox analyses. Conclusion: The results indicated that all the hits shared critical Pi-Pi stacked and hydrogen bond interactions with Tyr1230 and Met1160 respectively.



Author(s):  
Majid Ali ◽  
Syed Majid Bukhari ◽  
Asma Zaidi ◽  
Farhan A. Khan ◽  
Umer Rashid ◽  
...  

Background:: Structurally diverse organic compounds and available drugs were screened against urease and carbonic anhydrase II in a formulation acceptable for high-throughput screening. Objective: The study was conducted to find out potential inhibitors of urease and carbonic anhydrase II. Methods:: Quantification of the possible HITs was carried out by determining their IC50 values. Results and Discussion:: of several screened compounds including derivatives of oxadiazole, coumarins, chromane-2, 4- diones and metal complexes of cysteine-omeprazole showed promising inhibitory activities with IC50 ranging from 47 μM to 412 μM against the urease. The interactions of active compounds with active sites of enzymes were investigated through molecular docking studies which revealed that (R)-1-(4-amino-4-(5-(thiophen-2-yl)-1,3,4-oxadiazol-2-yl) butyl) guanidine possessing IC50 of 47 μM, interacts with one of the nickel metal atom of urease besides further interactions as predictable hydrogen bonds with KCX490, Asp633, His492, His407 and His409 along with Ala440 and 636. Bi-ligand metal complexes of 4-aminoantipyrine based Schiff bases showed activation of urease with AC50 ranging from 68 μM to 112 μM. Almost 21 compounds with varying functional groups including pyrimidines, oxadiazoles, imidazoles, hydrazides and tin based compounds were active carbonic anhydrase II inhibitors presenting 98 μM to 390 μM IC50 values. Several N-substituted sulfonamide derivatives were inactive against carbonic anhydrase II. Conclusion:: Among all the screened compounds, highly active inhibitor of carbonic anhydrase II was (4-(3- hydroxyphenyl)-6-phenyl-2-thioxo-1,2,3,4-tetrahydropyrimidin-5-yl)phenyl) methanone with IC50 of 98.0 μM. This particular compound showed metallic interaction with Zn ion of carbonic anhydrase II through hydroxyl group of phenyl ring.



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