Access to enantiopure β‐amino acids : β‐Aminopeptidases are hydrolases that possess the unique ability to cleave N‐terminal β‐amino acids from peptides and amides. Hydrolysis of racemic β‐amino acid amides catalyzed by these enzymes displays enantioselectivity with strong preference for substrates with the L ‐configuration, and gives access to various aliphatic β‐amino acids of high enantiopurity.
Turn Bak : We present rationally designed scaffolds that mimic the spatial projection of the i, i+4, i+7, and i+11 residues of an α‐helix. A library of biphenyl derivatives was shown by competition fluorescence polarization and ITC to mimic Bak and disrupt the Bak/Bcl‐xL protein–protein interaction. 15N HSQC experiments confirmed that the surface of Bcl‐xL normally occupied by Bak was the target area of our new synthetic inhibitors.
It's alarming : Bacterial alarmone guanosine 5′‐diphosphate 3′‐diphosphate (ppGpp), which is a key regulatory molecule that controls the stringent response, also exists in chloroplasts of plant cells. Cross‐linking experiments with 6‐thioguanosine 5′‐diphosphate 3′‐diphosphate (6‐thioppGpp) and chloroplast RNA polymerase indicate that ppGpp binds the β′ subunit of plastid‐encoded plastid RNA polymerase that corresponds to the Escherichia coli β′ subunit.
SDS‐concentration‐dependent α‐synuclein structure : Upon interaction with SDS, αSyn folds into a structure with two antiparallel α‐helices. We show from single‐molecule FRET that αSynn adopts this conformation in an all‐or‐none fashion below the SDS critical micelle concentration. Population of the folded species is directly coupled to an increase in α‐helix content; this suggests that the entire N terminus is involved in the transaction.
Protein unfolding inside immobilized polymerosomes : One of the most interesting properties of polymeric vesicles is their remarkable stability against extreme temperatures and osmotic stress, and their longevity even under harsh environmental conditions. We have demonstrated, in an application on protein folding, that surface‐tethered polymerosomes are suitable for performing time‐resolved single molecule studies with encapsulated proteins, as illustrated here.
Illuminating glucosidases : The shown photoaffinity probe for endoplasmic reticulum (ER) α‐glucosidases was found to be a highly potent inhibitor of α‐glucosidase I in vitro and equally effective at inhibiting cellular ER glucosidases, as determined by a free oligosaccharide (FOS) analysis.
Combating glycolipid storage disorders : LABNAc was prepared in an efficient 11‐step procedure from D ‐lyxonolactone. The enantiomer DABNAc was also prepared from L ‐lyxonolactone. Preliminary cellular studies indicate that these compounds may find utility as chemical chaperones for the treatment of Tay‐Sachs and Sandhoff diseases.
The role of β‐aminovinyl ketones as synthetic intermediates has been well categorised, but recent developments have shown an interesting array of applications and new chemotherapeutic potential, both in the preparation of biologically active heterocycles and as pharmacophores in their own right.
Choosing chloro : By reshaping the catalytic pocket of a catechol 1,2‐dioxygenase through a structural route alternative to evolution, novel engineered chlorocatechol dioxygenase‐like enzymes were obtained. Variants show an inversion of specificity with a preference for 4‐chlorocatechol and activity on the rarely recognised substrate 4,5‐dichlorocatechol.
Broad‐spectrum antibiotics with heterocyclic side chains strongly inhibit peroxidase‐catalyzed iodination in the presence of metallo‐β‐lactamase. This suggests that antibiotic resistance due to hydrolysis of the β‐lactam ring in antibiotics would have negative effects on thyroid activity.
Powerful pyrene probes : Two kinds of pyrene‐labeled oligonucleotides (HNA‐ and RNA‐skeleton probes) were explored. The enhanced fluorescence intensity in the monomer region and the disappearance of aggregate/excimer emission in duplexes has been successfully used to detect the hybridization of oligonucleotides.
Spicing it up with fluorine : Enantiomers of α‐fluorinated capsaicin 2 , have been prepared by organocatalytic electrophilic fluorination and have been used as probes for the binding conformation of capsaicin to the TRPV1 pain receptor. No enantiomeric bias is observed, thus suggesting an extended binding conformation along the molecular axis.
A fluorescent biosensor is described for 2Fe2S clusters that is composed of green fluorescent protein (GFP) fused to glutaredoxin 2 (Grx2), as illustrated here. 2Fe2S detection is based on the reduction of GFP fluorescence upon the 2Fe2S‐induced dimerization of GFP‐Grx2. This assay is sufficiently sensitive to detect submicromolar changes in 2Fe2S levels, thus making it suitable for high‐throughput measurements of metallocluster degradation and synthesis reactions.
Copper‐induced structural rearrangements of Aβ40 structure and its redox properties are described in this study. Electrochemical and fluorescent methods are used to characterise the behaviour of Aβ–Cu species. The data suggest that time‐dependent folding of Aβ–Cu species may cause changes in the redox potentials.
Discovering RNA–protein interactions : A library of photoMet‐containing peptides was synthesized by using an Arg‐ and Leu‐rich α‐helical amphiphilic peptide. Irradiation of mixtures of these peptides and Rev‐responsive element (RRE) hairpin RNA promoted formation of covalent adducts. Analysis of one adduct showed that U26 in the bulged stem is responsible for covalent bond formation with the carbene intermediate. This strategy can provide important structural information about RNA–peptide interactions.
Probing SAR : The 1‐(biphenyl‐4‐ylmethyl)‐1H‐benzo[d]imidazole moiety is known to be an essential structural component of telmisartan for PPARγ activation. This study focused on the substituents at position 2 of the benzimidazole in an attempt to optimize PPARγ activation. In particular, the elongation of the alkyl chain and the introduction of an aromatic ring system were studied (shown).
Through construction of an iminosugar library and in situ cell‐based screening, several iminosugar compounds with the ability to stimulate IFN‐γ secretion in vitro were discovered. Among these compounds, one was able to strongly induce IFN‐γ secretion and showed remarkable antibacterial effects in vivo.
Zinc‐dependent metalloproteinases such as matrix metalloproteinases (MMPs) and A disintegrin and metalloproteinases (ADAMs) are potential therapeutic targets in many diseases. To better understand their complex role in health and disease, new methodology for activity determination is under development. This concept gives an overview of the available methods for activity‐based proteomic research on these enzymes.
Two series of dimeric ligands for a G‐protein‐coupled receptor were prepared that differ by the interconnecting spacer system. Biological evaluation revealed that both dimeric series exhibit unique biological properties relative to their monomeric counterparts.
