Structural and Biochemical Characterization of Aldehyde Dehydrogenase 12, the Last Enzyme of Proline Catabolism in Plants.

Heterokonts, Alveolata protists, green algae from Charophyta and Chlorophyta divisions, and all Embryophyta plants possess an aldehyde dehydrogenase (ALDH) gene named ALDH12. Here, we provide a biochemical characterization of two ALDH12 family members from the lower plant Physcomitrella patens and higher plant Zea mays. We show that ALDH12 encodes an NAD-dependent glutamate γ-semialdehyde dehydrogenase (GSALDH), which irreversibly converts glutamate γ-semialdehyde (GSAL), a mitochondrial intermediate of the proline and arginine catabolism, to glutamate.

Two-dimensional spectroscopy for non-specialists.

Detailed studies of the excitation dynamics in photosynthetic pigment-proteins require an application of a wide range of spectroscopic methods. From the later part of the previous century, pump-probe and time-resolved fluorescence spectroscopy provided an impressive amount of information. Being simple to grasp, these methods are well-understood and widely used by the photosynthesis research community.

Structural adaptations of photosynthetic complex I enable ferredoxin-dependent electron transfer.

Photosynthetic complex I enables cyclic electron flow around photosystem I, a regulatory mechanism for photosynthetic energy conversion. We report a 3.3-angstrom-resolution cryo-electron microscopy structure of photosynthetic complex I from the cyanobacterium The model reveals structural adaptations that facilitate binding and electron transfer from the photosynthetic electron carrier ferredoxin.

LPS perception through taste-induced reflex in Drosophila melanogaster.

In flies, grooming serves several purposes, including protection against pathogens and parasites. Previously, we found Escherichia coli or lipopolysaccharides (LPS) can induce grooming behavior via activation of contact chemoreceptors on Drosophila wing. This suggested that specific taste receptors may contribute to this detection.

1,1-Diheterocyclic Ethylenes Derived from Quinaldine and Carbazole as New Tubulin-Polymerization Inhibitors: Synthesis, Metabolism, and Biological Evaluation.

We report the synthesis and metabolic and biological evaluation of a series of 17 novel heterocyclic derivatives of isocombretastatin-A4 (iso-CA-4) and their structure-activity relationships. Among these derivatives, the most active compound, 4f, inhibited the growth of a panel of seven cancer cell lines with an IC in the low nanomolar range. In addition, 4f showed interesting activity against CA-4-resistant colon-carcinoma cells and multidrug-resistant leukemia cells.

One-Pot Synthesis of 2-Styrylindoles from Ortho-Substituted Chloroenynes.

A facile one-pot synthesis of 2-styrylindoles, through Suzuki arylation of ortho-substituted chloroenynes followed by N-cyclization and N-demethylation, has been developed. A variety of 2-styrylindoles were obtained in good to excellent yields and were evaluated for their anticancer properties.

What does "NO-Synthase" stand for ?

Mammalian NO-Synthases (NOSs) are the enzymatic sources of Nitric Oxide (NO°), a paradigmatic gasotransmitter involved in many (patho)-physiological processes. The increasing number of available genomes led to the identification of hundreds of new NOS proteins throughout the kingdoms of life, calling for a global investigation of this family of proteins. These new NOSs are commonly believed to share the same structure, functioning and role as mammalian NOSs.

Anti-osteoclastic effects of C-glucosidic ellagitannins mediated by actin perturbation.

Actin subunits assemble into actin filaments whose dynamics and three-dimensional architectures are further regulated by a variety of cellular factors to establish the functional actin cytoskeleton. The C-glucosidic ellagitannin vescalagin and its simpler analogue vescalin, affect both the dynamics and the ultrastructure of the actin cytoskeleton by directly binding to F-actin. Herein, we show that in vitro, the two compounds induce the formation of distinct F-actin networks characterized by different superstructures and dynamics.

Contribution of protein Gar1 to the RNA-guided and RNA-independent rRNA:Ψ-synthase activities of the archaeal Cbf5 protein.

Archaeal RNA:pseudouridine-synthase (PUS) Cbf5 in complex with proteins L7Ae, Nop10 and Gar1, and guide box H/ACA sRNAs forms ribonucleoprotein (RNP) catalysts that insure the conversion of uridines into pseudouridines (Ψs) in ribosomal RNAs (rRNAs). Nonetheless, in the absence of guide RNA, Cbf5 catalyzes the in vitro formation of Ψ in Pyrococcus abyssi 23S rRNA and of Ψ in tRNAs. Using gene-disrupted strains of the hyperthermophilic archaeon Thermococcus kodakarensis, we studied the in vivo contribution of proteins Nop10 and Gar1 to the dual RNA guide-dependent and RNA-independent activities of Cbf5 on 23S rRNA.

Triple resonance EPR spectroscopy determines the Mn coordination to ATP.

Mn often serves as a paramagnetic substitute to Mg, providing means for exploring the close environment of Mg in many biological systems where it serves as an essential co-factor. This applies to proteins with ATPase activity, where the ATP hydrolysis requires the binding of Mg-ATP to the ATPase active site. In this context, it is important to distinguish between the Mn coordination mode with free ATP in solution as compared to the protein bound case.

Role of Arginine 117 in Substrate Recognition by Human Cytochrome P450 2J2.

The influence of Arginine 117 of human cytochrome P450 2J2 in the recognition of ebastine and a series of terfenadone derivatives was studied by site-directed mutagenesis. R117K, R117E, and R117L mutants were produced, and the behavior of these mutants in the hydroxylation of ebastine and terfenadone derivatives was compared to that of wild-type CYP2J2. The data clearly showed the importance of the formation of a hydrogen bond between R117 and the keto group of these substrates.

Design and Synthesis of Tubulin and Histone Deacetylase Inhibitor Based on iso-Combretastatin A-4.

Designing multitarget drugs have raised considerable interest due to their advantages in the treatment of complex diseases such as cancer. Their design constitutes a challenge in antitumor drug discovery. The present study reports a dual inhibition of tubulin polymerization and HDAC activity.

Surface ocean pH variations since 1689 CE and recent ocean acidification in the tropical South Pacific.

Increasing atmospheric CO from man-made climate change is reducing surface ocean pH. Due to limited instrumental measurements and historical pH records in the world's oceans, seawater pH variability at the decadal and centennial scale remains largely unknown and requires documentation. Here we present evidence of striking secular trends of decreasing pH since the late nineteenth century with pronounced interannual to decadal-interdecadal pH variability in the South Pacific Ocean from 1689 to 2011 CE.

Glycolate Induces Redox Tuning Of Photosystem II in Vivo: Study of a Photorespiration Mutant.

Bicarbonate removal from the nonheme iron at the acceptor side of photosystem II (PSII) was shown recently to shift the midpoint potential of the primary quinone acceptor Q to a more positive potential and lowers the yield of singlet oxygen (O) production. The presence of Q results in weaker binding of bicarbonate, suggesting a redox-based regulatory and protective mechanism where loss of bicarbonate or exchange of bicarbonate by other small carboxylic acids may protect PSII against O in vivo under photorespiratory conditions. Here, we compared the properties of Q in the Arabidopsis () photorespiration mutant deficient in peroxisomal HYDROXYPYRUVATE REDUCTASE1 (), which accumulates glycolate in leaves, with the wild type.

Plutonium isotopic signatures in soils and their variation (2011-2014) in sediment transiting a coastal river in the Fukushima Prefecture, Japan.

The Fukushima Daiichi Nuclear Power Plant (FDNPP) accident resulted in a significant release of radionuclides that were deposited on soils in Northeastern Japan. Plutonium was detected at trace levels in soils and sediments collected around the FDNPP. However, little is known regarding the spatial-temporal variation of plutonium in sediment transiting rivers in the region.

Evidence for late Pleistocene origin of Astyanax mexicanus cavefish.

Background: Cavefish populations belonging to the Mexican tetra species Astyanax mexicanus are outstanding models to study the tempo and mode of adaptation to a radical environmental change. They are currently assigned to two main groups, the so-called "old" and "new" lineages, which would have populated several caves independently and at different times. However, we do not have yet accurate estimations of the time frames of evolution of these populations.

Lycopene crystalloids exhibit singlet exciton fission in tomatoes.

Transient absorption studies conducted on in vitro lycopene aggregates, as well as on lycopene crystalloids inside tomato chromoplasts, reveal the appearance of a long-lived excited state, which we unambiguously identified as lycopene triplet. These triplet states must be generated by singlet exciton fission, which occurs from the lycopene 2Ag state. This is the first time the singlet fission process has ever been shown to occur in a biological material.

Direct evidence for high affinity blockade of Na1.6 channel subtype by huwentoxin-IV spider peptide, using multiscale functional approaches.

The Chinese bird spider huwentoxin-IV (HwTx-IV) is well-known to be a highly potent blocker of Na1.7 subtype of voltage-gated sodium (Na) channels, a genetically validated analgesic target, and thus promising as a potential lead molecule for the development of novel pain therapeutics. In the present study, the interaction between HwTx-IV and Na1.

Genome-wide relationship between R-loop formation and antisense transcription in Escherichia coli.

Transcription termination by Rho is essential for viability in various bacteria, including some major pathogens. Since Rho acts by targeting nascent RNAs that are not simultaneously translated, it also regulates antisense transcription. Here we show that RNase H-deficient mutants of Escherichia coli exhibit heightened sensitivity to the Rho inhibitor bicyclomycin, and that Rho deficiency provokes increased formation of RNA-DNA hybrids (R-loops) which is ameliorated by expression of the phage T4-derived R-loop helicase UvsW.

A multidrug ABC transporter with a taste for GTP.

During the evolution of cellular bioenergetics, many protein families have been fashioned to match the availability and replenishment in energy supply. Molecular motors and primary transporters essentially need ATP to function while proteins involved in cell signaling or translation consume GTP. ATP-Binding Cassette (ABC) transporters are one of the largest families of membrane proteins gathering several medically relevant members that are typically powered by ATP hydrolysis.

A Long-Lived Triplet State Is the Entrance Gateway to Oxidative Photochemistry in Green Fluorescent Proteins.

Though ubiquitously used as selective fluorescence markers in cellular biology, fluorescent proteins (FPs) still have not disclosed all of their surprising properties. One important issue, notably for single-molecule applications, is the nature of the triplet state, suggested to be the starting point for many possible photochemical reactions leading to phenomena such as blinking or bleaching. Here, we applied transient absorption spectroscopy to characterize dark states in the prototypical enhanced green fluorescent protein (EGFP) of hydrozoan origin and, for comparison, in IrisFP, a representative phototransformable FP of anthozoan origin.

A charge polarization model for the metal-specific activity of superoxide dismutases.

The pathogenicity of Staphylococcus aureus is enhanced by having two superoxide dismutases (SODs): a Mn-specific SOD and another that can use either Mn or Fe. Using 94 GHz electron-nuclear double resonance (ENDOR) and electron double resonance detected (ELDOR)-NMR we show that, despite their different metal-specificities, their structural and electronic similarities extend down to their active-site H- and N-Mn(ii) hyperfine interactions. However these interactions, and hence the positions of these nuclei, are different in the inactive Mn-reconstituted Escherichia coli Fe-specific SOD.

Stereocontrolled glycoside synthesis by activation of glycosyl sulfone donors with scandium(iii) triflate.

The activation of aryl glycosyl sulfone donors has been achieved using scandium(iii) triflate and has led to the selective preparation of α-mannosides resulting from a post-glycosylation anomerization.

Study of the Construction of the Tiacumicin B Aglycone.

Our study of the synthesis of the aglycone of tiacumicin B is discussed here. We imagined two possible strategies featuring a main retrosynthetic disconnection between C13 and C14. The first strategy was based on Suzuki-Miyaura cross-coupling of 1,1-dichloro-1-alkenes, but the failure of this pathway led us to use a Pd/Cu-dual-catalyzed cross-coupling of alkynes with allenes that had never been implemented before in a total synthesis context.

The NOS-like protein from the microalgae Ostreococcus tauri is a genuine and ultrafast NO-producing enzyme.

The exponential increase of genomes' sequencing has revealed the presence of NO-Synthases (NOS) throughout the tree of life, uncovering an extraordinary diversity of genetic structure and biological functions. Although NO has been shown to be a crucial mediator in plant physiology, NOS sequences seem present solely in green algae genomes, with a first identification in the picoplankton species Ostreococcus tauri. There is no rationale so far to account for the presence of NOS in this early-diverging branch of the green lineage and its absence in land plants.