Tailor made : We report the rational biosynthesis of C15 hydroxylated non‐quinone geldanamycin analogues by site‐directed mutagenesis of the geldanamycin polyketide synthase (PKS), together with a combination of post‐PKS tailoring genes. Rational biosynthetic engineering allowed the generation of geldanamycin derivatives, such as DHQ3 illustrated in the figure, which had superior pharmacological properties in comparison to the parent compound.
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.
Molecular requirements and determinants for efficient binding to CCR5 were interpreted by computational techniques based on comparative receptor structure modeling, advanced 3D‐QSAR, docking, and shape‐based virtual screening of commercially available entry blockers. Results of this study may be valuable for predicting new HIV entry‐blocking leads.
Designer label : A newly developed polarity‐sensitive fluorescent probe (DBHA) was combined with a tyrosine‐specific labelling method that uses transition metal catalysis, and was successfully used in local structural analysis of the Tyr108 domain in Cu/Zn superoxide dismutase (SOD; see scheme). The strategy presented here provides a new approach for studying the local polarity and conformation changes of this tyrosine domain in SOD under acid or heat denaturation conditions.
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.
Prodigiosin : Amido‐functionalised prodigiosin‐derived compounds were synthesised via a robust and efficient synthetic route. These compounds were then evaluated against 60 human cell lines consisting of nine diverse tumour cell types and their anticancer activities were assessed.
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.
Happy tree‐like friends . Using trypsin and α‐chymotrypsin cleavage sites as models, we show that the protease reactivity of peptide dendrimers, such as the structure illustrated in the figure, can be controlled by the degree of branching. Such a control provides a novel possibility to tune the biological properties of peptide dendrimers, and should be generally useful for their employment as functional biomolecule analogues, for example, in drug delivery applications.
Caught in a trap . In this study trapped polyketide species (see figure) were off‐loaded from a type III PKS by novel nonhydrolyzable malonyl coenzyme A analogues in which a methylene group or an oxygen atom replaces the sulfur atom of malonyl‐CoA. This strategy allows the straightforward characterisation of intermediates of polyketide biosynthesis by LC‐HR‐ESI‐MS/MS and provides valuable insights on the mechanism and timing of polyketide formation.
To be sniffed at : Several 1‐ and 2‐substituted 1H‐imidazoles and 2‐substituted oxazoles, oxazolines and pyrazines have been synthesized and tested as inhibitors of the cytochrome P450 enzymes CYP2A6 and CYP2A13. 1‐Substituted 1H‐imidazoles bearing short chains (pentyl, hexyl or hexenyl) were found to be potent inhibitors of both enzymes, and showed IC50 values of about 2 μM .
Decorating pradimicin : Three tailoring enzymes in the pradimicin biosynthetic pathway have been investigated. PdmN and PdmJ were identified as a D ‐amino acid ligase and a C‐5 P450 hydroxylase, respectively, whereas PdmW was deduced to be the C‐6 P450 hydroxylase.
More than meets the I : The biosynthetic gene cluster for indanomycin was identified from Streptomyces antibioticus NRRL 8167. The framework of the indanomycins includes a tetrahydropyran and a central indane ring system. The final module of the indanomycin polyketide synthase possesses an unusual terminal module lacking an integrated thioesterase.
Bridging the gap : The differences between medicinal chemistry at the industrial and academic levels raises the question: Is there a significant gap between the two spheres that requires attention, or should such differences be deemed natural, without the need to close the gap? Herein we provide perspectives on this issue, based in part on opinions expressed at a forum discussion held at ISMC 2008 in Vienna.
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.
Finding the right fit : Herein, we report on the development of novel steric probes and present initial insights into their interplay with DNA polymerases. Our findings provide experimental evidence for varied enzyme–substrate interactions that might account for the varied selectivity previously observed.
Particles to the rescue! The construction of cationic amino acid motifs on the surface of bacteriophage Qβ by genetic engineering or chemical conjugation gives particles that are potent inhibitors of the anticoagulant action of heparin, which is a common anticlotting agent subject to clinical overdose.
In tandem : High‐resolution TEM shows that during the initial stages of demosponge spicule formation, a primordial crystalline structure is formed within the axial filament. The recently developed electron diffraction tomography technique (ADT) reveals that the nanorods have a layered structure that matches smectitic phyllosilicates. These intracellular nanorods have been considered as precursors of mature spicules.
Direct stimulation of soluble guanylate cyclase (sGC) represents a promising therapeutic strategy for the treatment of a range of diseases, including the severely disabling pulmonary hypertension (PH). Optimization of the unfavorable DMPK profile of previous sGC stimulators provided riociguat, which is currently being investigated in phase III clinical trials for the oral treatment of PH.
