Chemical Control of Peptide Material Phase Transitions

Progressive solute-rich polymer phase transitions provide pathways for achieving ordered supramolecular assemblies. Intrinsically disordered protein domains specifically regulate information in biological networks via conformational ordering. Here we consider a molecular...

Conformational ordering of intrinsically disordered peptides for targeting translation initiation

Intrinsically disordered regions (IDRs) in proteins can regulate their activity by facilitating protein-protein interactions (PPIs) as exemplified in the recruitment of the eukaryotic translation initiation factor 4E (eIF4E) protein by the protein eIF4G. Deregulation of this PPI module is central to a broad spectrum of cancer related malignancies and its targeted inhibition through bioactive peptides is a promising strategy for therapeutic intervention. We have employed a structure-guided approach to rationally develop peptide derivatives from the intrinsically disordered eIF4G scaffold by incorporating non-natural amino acids that facilitates disorder-to-order transition. The conformational heterogeneity of these peptides and the degree of structural reorganization required to adopt the optimum mode of interaction with eIF4E underscores their differential binding affinities. The presence of a pre-structured local helical element in the ensemble of structures was instrumental in the efficient docking of the peptides on to the protein surface. These insights were exploited to further design features into the peptide to propagate bound-state conformations in solution which resulted in the generation of a potent eIF4E binder. The study illustrates the molecular basis of eIF4E recognition by a disordered epitope from eIF4G and its modulation to generate peptides that can potentially attenuate translation initiation in oncology.

Chemical Control of Peptide Material Phase Transitions

Progressive solute-rich polymer phase transitions provide pathways for achieving ordered supramolecular assemblies. Intrinsically disordered protein domains specifically regulate information in biological networks via conformational ordering. Here we consider a molecular tagging strategy to control ordering transitions in polymeric materials and provide a proof-of-principle minimal peptide phase network captured with a dynamic chemical network.<div><br></div><div><br></div>

Chemical Control of Peptide Material Phase Transitions

Progressive solute-rich polymer phase transitions provide pathways for achieving ordered supramolecular assemblies. Intrinsically disordered protein domains specifically regulate information in biological networks via conformational ordering. Here we consider a molecular tagging strategy to control ordering transitions in polymeric materials and provide a proof-of-principle minimal peptide phase network captured with a dynamic chemical network.<div><br></div><div><br></div>

Completing the picture of tolazamide polymorphism under extreme conditions: a low-temperature study

We present the results of an experimental and computational study of structural changes in two polymorphs of tolazamide {systematic name: 1-[(azepan-1-ylamino)carbonyl]-4-methylbenzenesulfonamide}, C14H21N3O3S, on cooling to 100 K and reverse heating. No phase transitions occurred in this temperature range. The anisotropy of the thermal expansion was different for the two polymorphs and differed from that reported previously for the hydrostatic compression. The changes in different intermolecular contacts responsible for the strain anisotropy were analysed. Relative shortening of the contacts was related directly to their initial length and reversely to the steric density around them. Increasing steric density is likely to be the driving force for the conformational ordering of the azepane ring under compression.

Sum-Frequency Generation Vibrational Spectroscopy Investigations of Phosphonic Acids on Anodic Aluminum Oxide Films

Self-assembled monolayers of alkyl phosphonic acids on anodic aluminum oxide (AlOx) surfaces are important as dielectric layers in thin film electronic devices. Assessing the properties and quality of these monolayers on amorphous AlOx is limited to a few surface-sensitive methods. In this work, we study using nonlinear optical measurements the molecular ordering in n-alkyl phosphonic acids with various alkyl chain lengths (6 to 18 carbons) deposited on AlOx and show the influence of temperature on stability and conformational order. The results demonstrate that the octadecylphosphonic acid has fewest defects in the chain orientation. A detailed comparison of the longest and the shortest alkyl chain revealed different behavior in conformational ordering upon annealing.

Effect of benzoic acid surface modified alumina nanoparticles on the mechanical properties and crystallization behavior of isotactic polypropylene nanocomposites

The CH–π interactions between polypropylene and functionalized alumina (BA-Al2O3) nanoparticles improve the mechanical performance and conformational ordering of nanocomposites.