Homoisoleucine: a translationally active leucine surrogate of expanded hydrophobic surface area.
Ontology highlight
ABSTRACT:
SUBMITTER: Van Deventer JA
PROVIDER: S-EPMC3149977 | biostudies-literature | 2011 Mar
REPOSITORIES: biostudies-literature
Publications
Homoisoleucine: a translationally active leucine surrogate of expanded hydrophobic surface area.
Van Deventer James A JA Fisk John D JD Tirrell David A DA
Chembiochem : a European journal of chemical biology 20110215 5
Similar Datasets
Project description:BackgroundMost of hydrophilic and hydrophobic residues are thought to be exposed and buried in proteins, respectively. In contrast to the majority of the existing studies on protein folding characteristics using protein structures, in this study, our aim was to design predictors for estimating relative solvent accessibility (RSA) of amino acid residues to discover protein folding characteristics from sequences.MethodsThe proposed 20 real-value RSA predictors were designed on the basis of the support vector regression method with a set of informative physicochemical properties (PCPs) obtained by means of an optimal feature selection algorithm. Then, molecular dynamics simulations were performed for validating the knowledge discovered by analysis of the selected PCPs.ResultsThe RSA predictors had the mean absolute error of 14.11% and a correlation coefficient of 0.69, better than the existing predictors. The hydrophilic-residue predictors preferred PCPs of buried amino acid residues to PCPs of exposed ones as prediction features. A hydrophobic spine composed of exposed hydrophobic residues of an α-helix was discovered by analyzing the PCPs of RSA predictors corresponding to hydrophobic residues. For example, the results of a molecular dynamics simulation of wild-type sequences and their mutants showed that proteins 1MOF and 2WRP_H16I (Protein Data Bank IDs), which have a perfectly hydrophobic spine, have more stable structures than 1MOF_I54D and 2WRP do (which do not have a perfectly hydrophobic spine).ConclusionsWe identified informative PCPs to design high-performance RSA predictors and to analyze these PCPs for identification of novel protein folding characteristics. A hydrophobic spine in a protein can help to stabilize exposed α-helices.
| S-EPMC5259910 | biostudies-literature
Project description:Amphipathic peptides with amino acids arranged in alternating patterns of hydrophobic and hydrophilic residues efficiently self-assemble into β-sheet bilayer nanoribbons. Hydrophobic side chain functionality is effectively buried in the interior of the putative bilayer of these nanoribbons. This study investigates consequences on self-assembly of increasing the surface area of aromatic side chain groups that reside in the hydrophobic core of nanoribbons derived from Ac-(XKXE)2 -NH2 peptides (X = hydrophobic residue). A series of Ac-(XKXE)2 -NH2 peptides incorporating aromatic amino acids of increasing molecular volume and steric profile (X = phenylalanine [Phe], homophenylalanine [Hph], tryptophan [Trp], 1-naphthylalanine [1-Nal], 2-naphthylalanine [2-Nal], or biphenylalanine [Bip]) were assessed to determine substitution effects on self-assembly propensity and on morphology of the resulting nanoribbon structures. Additional studies were conducted to determine the effects of incorporating amino acids of differing steric profile in the hydrophobic core (Ac-X1 KFEFKFE-NH2 and Ac-(X1,5 KFE)-NH2 peptides, X = Trp or Bip). Spectroscopic analysis by circular dichroism (CD) and Fourier transform infrared (FT-IR) spectroscopy indicated β-sheet formation for all variants. Self-assembly rate increased with peptide hydrophobicity; increased molecular volume of the hydrophobic side chain groups did not appear to induce kinetic penalties on self-assembly rates. Transmission electron microscopy (TEM) imaging indicated variation in fibril morphology as a function of amino acid in the X positions. This study confirms that hydrophobicity of amphipathic Ac-(XKXE)2 -NH2 peptides correlates to self-assembly propensity and that the hydrophobic core of the resulting nanoribbon bilayers has a significant capacity to accommodate sterically demanding functional groups. These findings provide insight that may be used to guide the exploitation of self-assembled amphipathic peptides as functional biomaterials.
| S-EPMC8349901 | biostudies-literature
Project description:mRNAs associated with microtubules during interphase, metaphase and the midbody stage of cytokinesis were sequenced. Selective midbody-localized RNAs were identified and their translational characteristics were studied.
2020-07-18 | GSE134476 | GEO
Project description:Block copolymer micelles have been used extensively as carriers for therapeutic drugs and diagnostic molecules. Here, we report the synthesis of nonionic, block copolypeptides, K(P) (x)(rac-L)(y), which have a "reversed" rod-coil structure composed of a hydrophilic, rod-like, ?-helical segment attached to a disordered, racemic hydrophobic segment. The self assembly of these block copolypeptides in water was studied, and their compositions were optimized to identify a sample, K(P) (100)(rac-L)(10), which is able to form well defined micelles that are very stable against dilution, high temperatures, and various media. Micelle structure was determined using a combination of electron microscopy and dynamic light scattering measurements. The potential of these micelles as drug delivery carriers was evaluated by encapsulation of the anticancer drug camptothecin. The drug containing micelles were found to be stable.
| S-EPMC3099414 | biostudies-literature
Project description:Antibody (Ab) validation is the procedure in which an Ab is thoroughly assayed for sensitivity and specificity in a given application. Validation of Abs against post-translationally modified (PTM) targets is particularly challenging because it requires specifically prepared antigen. Here we describe a novel validation method using surrogate proteins in a Western blot. The surrogate protein, which we termed 'MILKSHAKE,' is a modified maltose binding protein enzymatically conjugated to a peptide from the chosen target that is either modified or nonmodified at the residue of interest. The certainty of the residue's modification status can be used to confirm Ab specificity. This method also allows for Ab validation even in the absence or limited availability of treated cell lysates.
| S-EPMC10568613 | biostudies-literature
Project description:Recent advances in cardiovascular magnetic resonance (CMR) now allow the accurate and reproducible measurement of many aspects of cardiac and vascular structure and function, with prognostic data emerging for several key imaging biomarkers. These biomarkers are increasingly used in the evaluation of new drugs, devices and lifestyle modifications for the prevention and treatment of cardiovascular disease. This review outlines a conceptual framework for the application of imaging biomarkers to clinical trials, highlights several important CMR techniques which are in use in randomised studies, and reviews certain aspects of trial design, conduct and interpretation in relation to the use of CMR.
| S-EPMC3142342 | biostudies-other
Project description:miRNAs moderately inhibit the translation and enhance the degradation of their target mRNAs via cognate binding sites located predominantly in the 3'-untranslated regions (UTR). Paradoxically, miRNA targets are also polysome-associated. We studied the polysome association by the comparative translationally less-active light- and more-active heavy-polysome profiling of a wild type (WT) human cell line and its isogenic mutant (MT) with a disrupted DICER1 gene and, thus, mature miRNA production. As expected, the open reading frame (ORF) length is a major determinant of light- to heavy-polysome mRNA abundance ratios, but is rendered less powerful in WT than in MT cells by miRNA-regulatory activities. We also observed that miRNAs tend to target mRNAs with longer ORFs, and that adjusting the mRNA abundance ratio with the ORF length improves its correlation with the 3'-UTR miRNA-binding-site count. In WT cells, miRNA-targeted mRNAs exhibit higher abundance in light relative to heavy polysomes, i.e., light-polysome enrichment. In MT cells, the DICER1 disruption not only significantly abrogated the light-polysome enrichment, but also narrowed the mRNA abundance ratio value range. Additionally, the abrogation of the enrichment due to the DICER1 gene disruption, i.e., the decreases of the ORF-length-adjusted mRNA abundance ratio from WT to MT cells, exhibits a nearly perfect linear correlation with the 3'-UTR binding-site count. Transcription factors and protein kinases are the top two most enriched mRNA groups. Taken together, the results provide evidence for the light-polysome enrichment of miRNA-targeted mRNAs to reconcile polysome association and moderate translation inhibition, and that ORF length is an important, though currently under-appreciated, transcriptome regulation parameter.
| S-EPMC10741098 | biostudies-literature
Project description:The poor predictive accuracy of current computational enzyme design methods has led to low success rates of producing highly active variants that target non-natural substrates. In this report, a quantitative assessment approach based on molecular dynamics (MD) simulations was developed to eliminate false-positive enzyme designs at the computational stage. Taking cephradine hydrolase as an example, the apparent Michaelis binding constant (K m) and catalytic efficiency (k cat/K m) of designed variants were correlated with binding free energies and activation energy barriers, respectively, as calculated by molecular mechanics/Poisson-Boltzmann surface area (MM/PBSA) and molecular mechanics/generalized Born surface area (MM/GBSA) methods with explicit water considered based on general MD simulation protocols. The correlation results showed that both the MM/GBSA and MM/PBSA methods with a protein dielectric constant (ε p = 4) could rank the variants well based on the predicted binding free energies between enzyme and the substrate. Furthermore, the activation energy barriers calculated by the MM/PBSA method with an ε p = 24 correlated well with k cat/K m. Thus, false-positive variants obtained by the enzyme design program PRODA were eliminated prior to experimentation. Therefore, MD simulation-based quantitative assessment of designed variants greatly enhanced the predictive accuracy of computational enzyme design tools and should facilitate the construction of artificial enzymes with high catalytic activities toward non-natural substrates.
| S-EPMC9064048 | biostudies-literature
Project description:Infection-related development of phytopathogenic fungi is initiated by sensing and responding to plant surface cues. This response results in the formation of specialized infection structures, so-called appressoria. To unravel the program inducing appressoria in the biotrophic smut fungus Ustilago maydis, we exposed cells to a hydrophobic surface and the cutin monomer 16-hydroxy hexadecanoic acid. Genome-wide transcriptional profiling under these appressorium-inducing in vitro conditions revealed dramatic transcriptional changes in almost 20% of the genes. Comparisons with the U. maydis sho1 msb2 double mutant, lacking two putative sensors for plant surface cues, revealed that these plasma membrane receptors regulate a small subset of the surface cue-induced genes. These genes comprised mainly secreted proteins including plant cell wall degrading enzymes that facilitate plant penetration and secreted effectors that are essential virulence factors, with functions after penetration. Our data also demonstrate specific effects on two transcription factors that redirect the transcriptional regulatory network towards appressorium formation and plant penetration. Thus, plant surface cues prime U. maydis for biotrophic development.
2014-07-23 | GSE53947 | GEO
Project description:The filamentous bacterium Streptomyces coelicolor differentiates by forming specialized, spore-bearing aerial hyphae that grow into the air. Using microarrays, we identified genes that are down-regulated in a mutant unable to erect aerial hyphae. Through this route, we identified a previously unknown layer of aerial mycelium surface proteins (the "chaplins"). The chaplins share a hydrophobic domain of ~40 residues (the "chaplin domain"), and all have a secretion signal. The five short chaplins (ChpD,E,F,G,H) have one chaplin domain, whereas the three long chaplins (ChpA,B,C) have two chaplin domains and a C-terminal "sorting signal" that targets them for covalent attachment to the cell wall by sortase enzyme. Expression of the two chaplin genes examined (chpE, chpH) depended on aerial hyphae formation but not sporulation, and egfp fusions showed their expression localized to aerial structures. Mass spectrometry of cell wall extracts confirmed that the short chaplins localized to the cell surface. Deletion of chaplin genes caused severe delays in aerial hyphae formation, a phenotype rescued by exogenous application of chaplin proteins. These observations implicate the chaplins in aerial mycelium formation, and suggest that coating of the envelope by the chaplins is required for aerial hyphae to grow out of the aqueous environment of the substrate mycelium into the air. Set of arrays organized by shared biological context, such as organism, tumors types, processes, etc. Keywords: Logical Set
2007-07-20 | GSE8530 | GEO