Enzymatic Upgrading of Biomass-Derived Aldoses to Rare Deoxy Ketoses Catalyzed by Transketolase Variants.

A sustainable, convenient, scalable, one-step method for the two-carbon chain elongation of cheap and biomass-derived pentoses (l-arabinose, and 2-deoxy-d-ribose) and hexose l-rhamnose was developed to produce C deoxy ketoses (C-7 and C-8) using transketolase, an enzyme catalyzing the quasi-irreversible transfer of a ketol group from an α-keto acid to an aldehyde. Deoxygenated ketoses - commonly obtained by chemical synthesis - were afforded through a suitable combination of both nucleophile and electrophile substrates in the presence of rationally designed TK variants. Pyruvate as nucleophile with pentose l-arabinose (C-5) as electrophile gave 1-deoxy-L-gluco-heptulose (C-7), while ß-hydroxypyruvate (HPA) as nucleophile with acceptors 2-deoxy-d-ribose (C-5) and 6-deoxy-l-mannose (l-rhamnose) (C-6) led to formation of 4-deoxy-d-altro-heptulose (C-7) and 8-deoxy-l-glycero-l-galacto-octulose (C-8), respectively.

Probing Enzymatic PET Degradation: Molecular Dynamics Analysis of Cutinase Adsorption and Stability.

Understanding the mechanisms influencing poly(ethylene terephthalate) (PET) biodegradation is crucial for developing innovative strategies to accelerate the breakdown of this persistent plastic. In this study, we employed all-atom molecular dynamics simulation to investigate the adsorption process of the LCC-ICCG cutinase enzyme onto the PET surface. Our results revealed that hydrophobic, π-π, and H bond interactions, specifically involving aliphatic, aromatic, and polar uncharged amino acids, were the primary driving forces for the adsorption of the cutinase enzyme onto PET.

Synthesis, kinase inhibition and anti-leukemic activities of diversely substituted indolopyrazolocarbazoles.

Pyrazole analogues of the staurosporine aglycone K252c, in which the lactam ring was replaced by a pyrazole moiety, were synthesized. In this series, one or the other nitrogen atoms of the indolocarbazole scaffold was substituted by aminoalkyl chains, aiming at improving protein kinase inhibition as well as cellular potency toward acute myeloid leukemia (AML) cell lines. Compound 19a, substituted at the N12-position by a 3-(methylamino)propyl group, showed high cellular activity in the low micromolar range toward three AML cell lines (MOLM-13, OCI-AML3 and MV4-11) with selectivity over non-cancerous cells (NRK, H9c2).

-Ethyl-Isothiocitrullin-Based Dipeptides and 1,2,4-Oxadiazole Pseudo-Dipeptides: Solid Phase Synthesis and Evaluation as NO Synthase Inhibitors.

We previously reported dipeptidomimetic compounds as inhibitors of neuronal and/or inducible NO synthases (n/iNOS) with significant selectivity against endothelial NOS (eNOS). They were composed of an -ethylisothiocitrullin-like moiety linked to an extension through a peptide bond or a 1,2,4-oxadiazole link. Here, we developed two further series where the extension size was increased to establish more favorable interactions in the NOS substrate access channel.

Cage-like structures based on constrained cyclic arylopeptoids.

The access to cupola-like or tube-like structures from - and -arylopeptoid macrocycles was explored through CuAAC reaction using a partially flexible bis(azide) and Cu-N-heterocyclic carbene as catalyst. NMR studies showed that a bis-triazolium bicylic compound in the -series adopts well-defined structure in polar aprotic and protic solvents. Besides, preliminary study revealed its potential for oxoanion recognition.

Design, synthesis and biological evaluation of conformationnally-restricted analogues of E7010 as inhibitors of tubulin assembly (ITA) and vascular disrupting agents (VDA).

Vascular-disrupting agents (VDA) specifically target established neovasculature which results in vascular shutdown. This therapeutic strategy could improve the outcome of pathologies involving aberrant angiogenesis. Although several classes of VDA exist, inhibitors of tubulin assembly (ITA) represent the main category.

Synthesis and Kinase Inhibitory Potencies of Pyrazolo[3,4-]isoquinolines.

A new series of pyrazolo[3,4-]isoquinoline derivatives, diversely substituted at the 4- or 8-position, were synthesized. The results of the kinase inhibitory potency study demonstrated that the introduction of a bromine atom at the 8-position was detrimental to Haspin inhibition, while the introduction of an alkyl group at the 4-position led to a modification of the kinase inhibition profiles. Altogether, the results obtained demonstrated that new pyrazolo[3,4-]isoquinolines represent a novel family of kinase inhibitors with various selectivity profiles.

1,2,4-Triazole-3-thione analogues with an arylakyl group at position 4 as metallo-β-lactamase inhibitors.

Metallo-β-lactamases (MBLs) represent an increasingly serious threat to public health because of their increased prevalence worldwide in relevant opportunistic Gram-negative pathogens. MBLs efficiently inactivate widely used and most valuable β-lactam antibiotics, such as oxyiminocephalosporins (ceftriaxone, ceftazidime) and the last-resort carbapenems. To date, no MBL inhibitor has been approved for therapeutic applications.

QM/MM Study of Human Transketolase: Thiamine Diphosphate Activation Mechanism and Complete Catalytic Cycle.

A computational model for human transketolase was proposed, showing that thiamine diphosphate activation was based on His110 in place of His481 reported in yeast transketolase. In addition, a complete catalytic reaction pathway was investigated using d-xylulose-5-phosphate and d-ribose-5-phosphate as substrates, showing at every step a perfect superimposition of our model with high-resolution crystallographic structures 3MOS, 4KXV, and 4KXX. This study shows that H2N4' of the active thiamine diphosphate "V form" no longer has a self-activating role but allows self-stabilization of the cofactor and of the Breslow intermediate.

4-Alkyl-1,2,4-triazole-3-thione analogues as metallo-β-lactamase inhibitors.

In Gram-negative bacteria, the major mechanism of resistance to β-lactam antibiotics is the production of one or several β-lactamases (BLs), including the highly worrying carbapenemases. Whereas inhibitors of these enzymes were recently marketed, they only target serine-carbapenemases (e.g.

4-(-Alkyl- and -Acyl-amino)-1,2,4-triazole-3-thione Analogs as Metallo-β-Lactamase Inhibitors: Impact of 4-Linker on Potency and Spectrum of Inhibition.

To fight the increasingly worrying bacterial resistance to antibiotics, the discovery and development of new therapeutics is urgently needed. Here, we report on a new series of 1,2,4-triazole-3-thione compounds as inhibitors of metallo-β-lactamases (MBLs), which represent major resistance determinants to β-lactams, and especially carbapenems, in Gram-negative bacteria. These molecules are stable analogs of 4-amino-1,2,4-triazole-derived Schiff bases, where the hydrazone-like bond has been reduced (hydrazine series) or the 4-amino group has been acylated (hydrazide series); the synthesis and physicochemical properties thereof are described.

Functionalization of 9-thioxanthone at the 1-position: From arylamino derivatives to [1]benzo(thio)pyrano[4,3,2-de]benzothieno[2,3-b]quinolines of biological interest.

Original 1-amino substituted thioxanthone derivatives were easily prepared from the bare heterocycle by a deprotometalation-iodolysis-copper-catalyzed CN bond formation sequence. This last reaction delivered mono- or/and diarylated products depending on the aniline involved. 1-Amino-9-thioxanthone was also prepared and reacted with 2-iodoheterocycles.

Pyridin-2(1H)one derivatives: A possible new class of therapeutics for mechanical allodynia.

Mechanical Allodynia (MA), a frequent chronic pain symptom caused by innocuous stimuli, constitutes an unmet medical need, as treatments using analgesics available today are not always effective and can be associated with important side-effects. A series of 3,5-disubstituted pyridin-2(1H)-ones was designed, synthesized and evaluated in vivo toward a rat model of inflammatory MA. We found that the series rapidly and strongly prevented the development of MA.

Kinase inhibitions in pyrido[4,3-h] and [3,4-g]quinazolines: Synthesis, SAR and molecular modeling studies.

New pyrido[3,4-g]quinazoline derivatives were prepared and evaluated for their inhibitory potency toward 5 protein kinases (CLK1, DYRK1A, GSK3, CDK5, CK1). A related pyrido[4,3-h]quinazoline scaffold with an angular structure was also synthesized and its potency against the same protein kinase panel was compared to the analogous pyrido[3,4-g]quinazoline. Best results were obtained for 10-nitropyrido[3,4-g]quinazoline 4 toward CLK1 with nanomolar activities.

NCα-gem-dimethylated peptoid side chains: A novel approach for structural control and peptide sequence mimetics.

The design of linear peptoid oligomers adopting well-defined secondary structures while mimicking defined peptide primary sequences is a major challenge in the context of drug discovery. To this end, chemists have developed cis-inducing peptoid side chains to build robust polyproline type I helices. However, the number of efficient examples remains scarce and chemical diversity accessible through the use of these side chains is limited.

Synthesis of Branched-Chain Sugars with a DHAP-Dependent Aldolase: Ketones are Electrophile Substrates of Rhamnulose-1-phosphate Aldolases.

Dihydroxyacetone phosphate (DHAP)-dependent rhamnulose aldolases display an unprecedented versatility for ketones as electrophile substrates. We selected and characterized a rhamnulose aldolase from Bacteroides thetaiotaomicron (RhuABthet) to provide a proof of concept. DHAP was added as a nucleophile to several α-hydroxylated ketones used as electrophiles.

Topologically Diverse Shapes Accessible by Modular Design of Arylopeptoid Macrocycles.

N-Substituted aromatic cyclooligoamides composed of different combinations of ortho-, meta-, and/or para-arylopeptoid residues carrying methoxyethyl side chains have been efficiently synthesized by macrocyclization of the corresponding linear oligomers. The study of the architectures of these macrocycles in solution and solid state has revealed that tetracyclic arylopeptoids adopt sequence-dependent shapes with different backbone amide conformations and side-chain orientations. Remarkably, despite the absence of intramolecular H-bonding ability, some of these arylopeptoid macrocycles show well-defined architectures in solution.

1,2,4-Triazole-3-thione Compounds as Inhibitors of Dizinc Metallo-β-lactamases.

Metallo-β-lactamases (MBLs) cause resistance of Gram-negative bacteria to β-lactam antibiotics and are of serious concern, because they can inactivate the last-resort carbapenems and because MBL inhibitors of clinical value are still lacking. We previously identified the original binding mode of 4-amino-2,4-dihydro-5-(2-methylphenyl)-3H-1,2,4-triazole-3-thione (compound IIIA) within the dizinc active site of the L1 MBL. Herein we present the crystallographic structure of a complex of L1 with the corresponding non-amino compound IIIB (1,2-dihydro-5-(2-methylphenyl)-3H-1,2,4-triazole-3-thione).

Synthesis and preliminary in vitro kinase inhibition evaluation of new diversely substituted pyrido[3,4-g]quinazoline derivatives.

The synthesis of new diversely substituted pyrido[3,4-g]quinazolines is described. The inhibitory potencies of prepared compounds toward a panel of five CMGC protein kinases (CDK5, CLK1, DYRK1A, CK1, GSK3), that are known to play a potential role in Alzheimer's disease, were evaluated. The best overall kinase inhibition profile was found for nitro compound 4 bearing an ethyl group at the 5-position.

Synthesis and biological activity of pyrazole analogues of the staurosporine aglycon K252c.

A derivative of the staurosporine aglycon (K252c), in which the lactam ring was replaced by a pyrazole moiety, was synthesized. The resulting indolopyrazolocarbazole (3) inhibited Pim isoforms 1-3 whereas it did not impair the activity of two known targets of K252c, protein kinase C isoforms α and γ. Compound 3 exhibited moderate cytotoxic activity toward human leukemia and colon carcinoma cell lines (K562 and HCT116), strongly suggesting that this new scaffold deserves further investigations for treatment of malignancies associated with Pim activity.

Discovery of pyrido[3,4-g]quinazoline derivatives as CMGC family protein kinase inhibitors: Design, synthesis, inhibitory potency and X-ray co-crystal structure.

The design and synthesis of new pyrido[3,4-g]quinazoline derivatives is described as well as their protein kinase inhibitory potencies toward five CMGC family members (CDK5, CK1, GSK3, CLK1 and DYRK1A). The interest for this original tricyclic heteroaromatic scaffold as modulators of CLK1/DYRK1A activity was validated by nanomolar potencies (compounds 12 and 13). CLK1 co-crystal structures with two inhibitors revealed the binding mode of these compounds within the ATP-binding pocket.

Insights into the Thiamine Diphosphate Enzyme Activation Mechanism: Computational Model for Transketolase Using a Quantum Mechanical/Molecular Mechanical Method.

We propose the first computational model for transketolase (TK), a thiamine diphosphate (ThDP)-dependent enzyme, using a quantum mechanical/molecular mechanical method on the basis of crystallographic TK structures from yeast and Escherichia coli, together with experimental kinetic data reported in the literature with wild-type and mutant TK. This model allowed us to define a new route for ThDP activation in the enzyme environment. We evidenced a strong interaction between ThDP and Glu418B of the TK active site, itself stabilized by Glu162A.

New N-1,N-10-bridged pyrrolo[2,3-a]carbazole-3-carbaldehydes: synthesis and biological activities.

The synthesis of new pyrrolocarbazoles substituted at N-1/N-10 positions is described. All the compounds tested demonstrated moderate to high Pim-1/Pim-3 kinase inhibitory potency. The most active inhibitors identified in this series (3, 17) have an alkyl chain bridging the N-1 and N-10 positions.

New potent and selective inhibitor of Pim-1/3 protein kinases sensitizes human colon carcinoma cells to doxorubicin.

The Pim protein kinases (provirus insertion site of Moloney murine leukemia virus) have been identified as important actors involved in tumor cell survival, proliferation, migration and invasion. Therefore, inhibition of Pim activity by low molecular weight compounds is under investigation as a part of anticancer therapeutic strategies. We have synthesized a series of pyrrolo[2,3-a]carbazole derivatives that significantly inhibited Pim protein kinases at submicromolar concentrations.