scholarly journals TADOSS: computational estimation of tandem domain swap stability

2018 ◽  
Vol 35 (14) ◽  
pp. 2507-2508 ◽  
Author(s):  
Aleix Lafita ◽  
Pengfei Tian ◽  
Robert B Best ◽  
Alex Bateman

Abstract Summary Proteins with highly similar tandem domains have shown an increased propensity for misfolding and aggregation. Several molecular explanations have been put forward, such as swapping of adjacent domains, but there is a lack of computational tools to systematically analyze them. We present the TAndem DOmain Swap Stability predictor (TADOSS), a method to computationally estimate the stability of tandem domain-swapped conformations from the structures of single domains, based on previous coarse-grained simulation studies. The tool is able to discriminate domains susceptible to domain swapping and to identify structural regions with high propensity to form hinge loops. TADOSS is a scalable method and suitable for large scale analyses. Availability and implementation Source code and documentation are freely available under an MIT license on GitHub at https://github.com/lafita/tadoss. Supplementary information Supplementary data are available at Bioinformatics online.

Author(s):  
Zachary B Abrams ◽  
Dwayne G Tally ◽  
Lynne V Abruzzo ◽  
Kevin R Coombes

Abstract Summary Cytogenetics data, or karyotypes, are among the most common clinically used forms of genetic data. Karyotypes are stored as standardized text strings using the International System for Human Cytogenomic Nomenclature (ISCN). Historically, these data have not been used in large-scale computational analyses due to limitations in the ISCN text format and structure. Recently developed computational tools such as CytoGPS have enabled large-scale computational analyses of karyotypes. To further enable such analyses, we have now developed RCytoGPS, an R package that takes JSON files generated from CytoGPS.org and converts them into objects in R. This conversion facilitates the analysis and visualizations of karyotype data. In effect this tool streamlines the process of performing large-scale karyotype analyses, thus advancing the field of computational cytogenetic pathology. Availability and Implementation Freely available at https://CRAN.R-project.org/package=RCytoGPS. The code for the underlying CytoGPS software can be found at https://github.com/i2-wustl/CytoGPS. Supplementary information There is no supplementary data.


2019 ◽  
Vol 35 (21) ◽  
pp. 4459-4461 ◽  
Author(s):  
Sha Gong ◽  
Chengxin Zhang ◽  
Yang Zhang

Abstract Motivation Comparison of RNA 3D structures can be used to infer functional relationship of RNA molecules. Most of the current RNA structure alignment programs are built on size-dependent scales, which complicate the interpretation of structure and functional relations. Meanwhile, the low speed prevents the programs from being applied to large-scale RNA structural database search. Results We developed an open-source algorithm, RNA-align, for RNA 3D structure alignment which has the structure similarity scaled by a size-independent and statistically interpretable scoring metric. Large-scale benchmark tests show that RNA-align significantly outperforms other state-of-the-art programs in both alignment accuracy and running speed. The major advantage of RNA-align lies at the quick convergence of the heuristic alignment iterations and the coarse-grained secondary structure assignment, both of which are crucial to the speed and accuracy of RNA structure alignments. Availability and implementation https://zhanglab.ccmb.med.umich.edu/RNA-align/. Supplementary information Supplementary data are available at Bioinformatics online.


2021 ◽  
Author(s):  
Zachary B. Abrams ◽  
Dwayne G. Tally ◽  
Lynne V. Abruzzo ◽  
Kevin R. Coombes

AbstractSummaryCytogenetics data, or karyotypes, are among the most common clinically used forms of genetic data. Karyotypes are stored as standardized text strings using the International System for Human Cytogenomic Nomenclature (ISCN). Historically, these data have not been used in large-scale computational analyses due to limitations in the ISCN text format and structure. Recently developed computational tools such as CytoGPS have enabled large-scale computational analyses of karyotypes. To further enable such analyses, we have now developed RCytoGPS, an R package that takes JSON files generated from CytoGPS.org and converts them into objects in R. This conversion facilitates the analysis and visualizations of karyotype data. In effect this tool streamlines the process of performing large-scale karyotype analyses, thus advancing the field of computational cytogenetic pathology.Availability and ImplementationFreely available at https://CRAN.R-project.org/package=RCytoGPSSupplementary informationSupplementary data are available at Bioinformatics online.


2021 ◽  
Author(s):  
Mohsen Sadeghi ◽  
Frank Noe

Shaping and remodeling of biomembranes is essential for cellular trafficking, with membrane-binding peripheral proteins playing the key role in it. Significant membrane remodeling as in endo- and exocytosis is often due to clusters or aggregates of many proteins whose interactions may be direct or mediated via the membrane. While computer simulation could be an important tool to disentangle these interactions and understand what drives cooperative protein interactions in membrane remodeling, this has so far been extremely challenging: protein-membrane systems involve time- and lengthscales that make detailed atomistic simulations impractical, while most coarse-grained models lack the degree of detail needed to resolve the dynamics and physical effect of protein and membrane flexibility. Here, we develop a coarse-grained model of the bilayer membrane bestrewed with rotationally-symmetric flexible membrane-bound proteins. We show how this model can be parameterized based on local curvatures, protein flexibility, and the in-plane dynamics of proteins. We measure the effective interaction potential for the membrane-mediated interactions between peripheral proteins. Furthermore, we investigate the kinetics, equilibrium distributions, and the free energy landscape governing the formation and break-up of protein clusters on the surface of the membrane. We demonstrate how the flexibility of the protein plays a deciding role in highly selective macroscopic aggregation behavior. Finally, we present large-scale simulations of membrane tubulation, and discuss the sequence of events and the stability of intermediates.


2021 ◽  
Author(s):  
Mohsen Sadeghi ◽  
Frank Noé

Abstract Shaping and remodeling of biomembranes is essential for cellular trafficking, with membrane-binding peripheral proteins playing the key role in it. Significant membrane remodeling as in endo- and exocytosis is often due to clusters or aggregates of many proteins whose interactions may be direct or mediated via the membrane. While computer simulation could be an important tool to disentangle these interactions and understand what drives cooperative protein interactions in membrane remodeling, this has so far been extremely challenging: protein-membrane systems involve time- and lengthscales that make detailed atomistic simulations impractical, while most coarse-grained models lack the degree of detail needed to resolve the dynamics and physical effect of protein and membrane flexibility. Here, we develop a coarse-grained model of the bilayer membrane bestrewed with rotationally-symmetric flexible membrane-bound proteins. We show how this model can be parameterized based on local curvatures, protein flexibility, and the in-plane dynamics of proteins. We measure the effective interaction potential for the membrane-mediated interactions between peripheral proteins. Furthermore, we investigate the kinetics, equilibrium distributions, and the free energy landscape governing the formation and break-up of protein clusters on the surface of the membrane. We demonstrate how the flexibility of the protein plays a deciding role in highly selective macroscopic aggregation behavior. Finally, we present large-scale simulations of membrane tubulation, and discuss the sequence of events and the stability of intermediates.


2005 ◽  
Vol 33 (5) ◽  
pp. 910-912 ◽  
Author(s):  
P.J. Bond ◽  
J. Cuthbertson ◽  
M.S.P. Sansom

Interactions between membrane proteins and detergents are important in biophysical and structural studies and are also biologically relevant in the context of folding and transport. Despite a paucity of high-resolution data on protein–detergent interactions, novel methods and increased computational power enable simulations to provide a means of understanding such interactions in detail. Simulations have been used to compare the effect of lipid or detergent on the structure and dynamics of membrane proteins. Moreover, some of the longest and most complex simulations to date have been used to observe the spontaneous formation of membrane protein–detergent micelles. Common mechanistic steps in the micelle self-assembly process were identified for both α-helical and β-barrel membrane proteins, and a simple kinetic mechanism was proposed. Recently, simplified (i.e. coarse-grained) models have been utilized to follow long timescale transitions in membrane protein–detergent assemblies.


Catalysts ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 757
Author(s):  
Huiyi Shang ◽  
Danni Yang ◽  
Dairong Qiao ◽  
Hui Xu ◽  
Yi Cao

Levan has wide applications in chemical, cosmetic, pharmaceutical and food industries. The free levansucrase is usually used in the biosynthesis of levan, but the poor reusability and low stability of free levansucrase have limited its large-scale use. To address this problem, the surface-displayed levansucrase in Saccharomyces cerevisiae were generated and evaluated in this study. The levansucrase from Zymomonas mobilis was displayed on the cell surface of Saccharomyces cerevisiae EBY100 using a various yeast surface display platform. The N-terminal fusion partner is based on a-agglutinin, and the C-terminal one is Flo1p. The yield of levan produced by these two whole-cell biocatalysts reaches 26 g/L and 34 g/L in 24 h, respectively. Meanwhile, the stability of the surface-displayed levansucrases is significantly enhanced. After six reuses, these two biocatalysts retained over 50% and 60% of their initial activities, respectively. Furthermore, the molecular weight and polydispersity test of the products suggested that the whole-cell biocatalyst of levansucrase displayed by Flo1p has more potentials in the production of levan with low molecular weight which is critical in certain applications. In conclusion, our method not only enable the possibility to reuse the enzyme, but also improves the stability of the enzyme.


Genetics ◽  
1974 ◽  
Vol 76 (2) ◽  
pp. 289-299
Author(s):  
Margaret McCarron ◽  
William Gelbart ◽  
Arthur Chovnick

ABSTRACT A convenient method is described for the intracistronic mapping of genetic sites responsible for electrophoretic variation of a specific protein in Drosophila melanogaster. A number of wild-type isoalleles of the rosy locus have been isolated which are associated with the production of electrophoretically distinguishable xanthine dehydrogenases. Large-scale recombination experiments were carried out involving null enzyme mutants induced on electrophoretically distinct wild-type isoalleles, the genetic basis for which is followed as a nonselective marker in the cross. Additionally, a large-scale recombination experiment was carried out involving null enzyme rosy mutants induced on the same wild-type isoallele. Examination of the electrophoretic character of crossover and convertant products recovered from the latter experiment revealed that all exhibited the same parental electrophoretic character. In addition to documenting the stability of the xanthine dehydrogenase electrophoretic character, this observation argues against a special mutagenesis hypothesis to explain conversions resulting from allele recombination studies.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Samaneh Pasban ◽  
Heidar Raissi

AbstractHexakis (m-phenylene ethynylene) (m-PE) macrocycles, with aromatic backbones and multiple hydrogen-bonding side chains, had a very high propensity to self-assemble via H-bond and π–π stacking interactions to form nanotubular structures with defined inner pores. Such stacking of rigid macrocycles is leading to novel applications that enable the researchers to explored mass transport in the sub-nanometer scale. Herein, we performed density functional theory (DFT) calculations to examine the drug delivery performance of the hexakis dimer as a novel carrier for doxorubicin (DOX) agent in the chloroform and water solvents. Based on the DFT results, it is found that the adsorption of DOX on the carrier surface is typically physisorption with the adsorption strength values of − 115.14 and − 83.37 kJ/mol in outside and inside complexes, respectively, and so that the essence of the drug remains intact. The negative values of the binding energies for all complexes indicate the stability of the drug molecule inside and outside the carrier's cavities. The energy decomposition analysis (EDA) has also been performed and shown that the dispersion interaction has an essential role in stabilizing the drug-hexakis dimer complexes. To further explore the electronic properties of dox, the partial density of states (PDOS and TDOS) are calculated. The atom in molecules (AIM) and Becke surface (BS) methods are also analyzed to provide an inside view of the nature and strength of the H-bonding interactions in complexes. The obtained results indicate that in all studied complexes, H-bond formation is the driving force in the stabilization of these structures, and also chloroform solvent is more favorable than the water solution. Overall, our findings offer insightful information on the efficient utilization of hexakis dimer as drug delivery systems to deliver anti-cancer drugs.


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