Less than 6 feet under : Serum proteins C3, C4, and α2M each contain a thioester domain buried within a hydrophobic pocket, which is thought to shield the labile thioester from hydrolysis. Herein, we make use of the inherent reactivity of the hydrazide for thioester moieties to chemoselectively label these crucial serum regulators in their native conformation; this demonstrates that access to the thioester site is much greater than previously supposed.
Two steps to click iodine : We have developed a two‐step reaction for protein iodination using click chemistry. With this method, which is summarized in the scheme, covalent attachment of a stable iodine‐containing aromatic azide moiety to an alkyne‐containing protein was achieved.
Matrix refolded : The formation of inclusion bodies, which are amorphous aggregates of misfolded insoluble protein, during recombinant protein expression, is one of the biggest bottlenecks in protein science. We report a stepwise, rational optimization procedure for refolding of insoluble proteins (see scheme). In comparison to refolding in‐solution, this parallelized, matrix‐assisted approach allows the refolding of various proteins in a fast and efficient manner.
Uranyl ion‐specific DNAzyme : A DNAzyme (lower strand) cleaves the substrate (upper strand) in the presence of the uranyl ion. The enzyme folds into a bulged three‐way‐junction structure with catalytically important nucleotides residing in the bulge. A highly conserved G?A mismatch is also crucial for the enzyme's activity.
Setting the right target : Most researchers who use small RNAs in mammalian cells assume that mRNA will be the target. Recent studies suggest that small RNAs can also target chromosomal DNA.
Demystifying Taxol : The structurally complex natural product paclitaxel is among the most important antitumor drugs presently in the clinic. While the mechanism of action is known, the biologically active conformation has been much debated. Herein we summarize the considerable research efforts that have gone into elucidating the bioactive conformation of paclitaxel.
Highly specific protein labeling : Photogenerated quinine methides (QMs) can act as highly specific light‐controllable protein affinity labeling reagents, broadening their applications to the study of protein–ligand and protein–protein interactions. The reactions between QMs and nucleophiles are less heterogeneous than those of other photogenerated active intermediates such as carbenes and nitrenes, making it easier to identify labeled species.
Antifolate labels : Molecules that bind specifically and with high affinity to proteins can be developed into powerful tools for chemical biology. The interaction between substituted 5‐benzyl pyrimidines and dihydrofolate reductase can be exploited for chemically labeling fusion proteins in mammalian cells.
Dye‐sensitized photosynthesis : Eosin Y (EY), a dye photosensitizer, works efficiently as a molecular photoelectrode by catalyzing the visible‐light‐driven electron‐transfer reaction for efficient regeneration of NADH through a photosensitizer–electron relay dyad. Injection of the photosensitized electron resulted in highly accelerated regeneration of NADH, which can be used by glutamate dehydrogenase for the photosynthesis of L ‐glutamate.
See you later amyloid β : A screen of a small library of oxime oligomers with an HTS fluorescence assay for amyloid fibril inhibition and subsequent investigation by atomic force microscopy revealed two new micromolar inhibitors of amyloid fibril formation. These new inhibitors have IC50 values in the 10 μM range.
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).
Molecules that inhibit store‐operated calcium entry (SOCE) are potentially useful immunomodulating agents. The identification of proteins involved in this pathway may further enable the identification of selective inhibitors. Herein we document some examples of the small‐molecule inhibitors of SOCE that have been reported to date. We also describe methods that were used to characterize the mechanism of action of these inhibitors.
Oxidation of a specific cysteine residue to Cα‐formylglycine is a novel post‐translational modification that is directed by a short recognition motif commonly found in pro‐ and eukaryotic sulfatases. As recently shown by C. Bertozzi and co‐workers, this system can be employed in protein engineering to equip proteins with genetically encoded aldehyde tags for site‐specific labeling, conjugation and immobilization.
Less is more : By starting with a high‐affinity HER2‐binding 3‐helix affibody molecule, we successfully developed 2‐helix small protein binders with 5 nM affinities by using a combination of several different strategies. Our efforts clearly suggest that 2‐helix small proteins against important tumor targets can be obtained by rational protein design and engineering.
Plaque visualisation : We identified three different D ‐enantiomeric peptides that bind to Alzheimer's amyloid β (Aβ1‐42). As there is currently no definitive pre‐mortem diagnosis for Alzheimer's disease, we investigated the peptides' suitability as molecular probes for in vivo imaging in transgenic mouse models.
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.
Flexibility required : We designed intramolecular bipartite tetracysteine sites in loops of p53 and the β‐sheets of EmGFP. We found that ReAsH binding preferentially favors tetracysteine sites with flexible geometries such as loops; flexibility was assessed by comparing Cα B‐factor values. This information is important for directing successful bipartite tetracysteine site designs.
RAR and RXR agonists : A collection of pyrazine‐based RAR/RXR ligands were prepared by a series of palladium catalyzed cross‐coupling reactions and characterized. Structure–activity relationships were elucidated. Retinoic acid receptor (RAR) α/β‐subtype‐selective and retinoid X receptor (RXR) inverse agonist activities are described for pyrazine acrylic acid arotinoid, 14 d .
Binding of the mGlu2/3 antagonist HYDIA in the closed conformation model of mGlu2 causes repulsive interactions with Y216 in lobe II of the binding pocket, preventing closure of the VFT.
