The prevalence of metabolic diseases, such as obesity, diabetes, metabolic syndrome and chronic liver diseases among others, has been rising for several years. Epidemiology and mechanistic (in vivo, in vitro and in silico) toxicology have recently provided compelling evidence implicating the chemical environment in the pathogenesis of these diseases. In this review, we will describe the biological processes that contribute to the development of metabolic diseases targeted by metabolic disruptors, and will propose an integrated pathophysiological vision of their effects on several organs. With regard to these pathomechanisms, we will discuss the needs, and the stakes of evolving the testing and assessment of endocrine disruptors to improve the prevention and management of metabolic diseases that have become a global epidemic since the end of last century.
- MeSH
- endokrinní disruptory * toxicita MeSH
- fenoly MeSH
- lidé MeSH
- metabolický syndrom * MeSH
- obezita chemicky indukované MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
Here, we report on the biochemical characterization of a new glycosylated bacteriocin (glycocin), ASM1, produced by Lactobacillus plantarum A-1 and analysis of the A-1 bacteriocinogenic genes. ASM1 is 43 amino acids in length with Ser18-O- and Cys43-S-linked N-acetylglucosamine moieties that are essential for its inhibitory activity. Its only close homologue, glycocin F (GccF), has five amino acid substitutions all residing in the flexible C-terminal 'tail' and a lower IC50 (0.9 nm) compared to that of ASM1 (1.5 nm). Asm/gcc genes share the same organization (asmH← →asmABCDE→F), and the asm genes reside on an 11 905-bp plasmid dedicated to ASM1 production. The A-1 genome also harbors a gene encoding a 'rare' bactofencin-type bacteriocin. As more examples of prokaryote S-GlcNAcylation are discovered, the functions of this modification may be understood.
- MeSH
- bakteriální geny genetika MeSH
- bakteriociny chemie genetika metabolismus MeSH
- fylogeneze MeSH
- glykosylace MeSH
- Lactobacillus plantarum chemie genetika MeSH
- novobiocin MeSH
- plazmidy genetika MeSH
- sekvence aminokyselin MeSH
- sekvence nukleotidů MeSH
- sekvenční analýza DNA MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Humoral immunity in mammals relies on the function of two developmentally and functionally distinct B-cell subsets-B1 and B2 cells. While B2 cells are responsible for the adaptive response to environmental antigens, B1 cells regulate the production of polyreactive and low-affinity antibodies for innate humoral immunity. The molecular mechanism of B-cell specification into different subsets is understudied. In this study, we identified lysine methyltransferase NSD2 (MMSET/WHSC1) as a critical regulator of B1 cell development. In contrast to its minor impact on B2 cells, deletion of the catalytic domain of NSD2 in primary B cells impairs the generation of B1 lineage. Thus, NSD2, a histone H3 K36 dimethylase, is the first-in-class epigenetic regulator of a B-cell lineage in mice.
- MeSH
- analýza přežití MeSH
- B-lymfocyty metabolismus MeSH
- histonlysin-N-methyltransferasa chemie metabolismus MeSH
- histony metabolismus MeSH
- humorální imunita MeSH
- katalytická doména * MeSH
- lysin metabolismus MeSH
- metylace MeSH
- myši inbrední C57BL MeSH
- novorozená zvířata MeSH
- přesmyk imunoglobulinových tříd MeSH
- vztahy mezi strukturou a aktivitou MeSH
- zárodečné centrum lymfatické uzliny metabolismus MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
Tick-borne encephalitis virus (TBEV), a member of flaviviruses, represents a serious health threat by causing human encephalitis mainly in central and eastern Europe, Russia, and northeastern Asia. As no specific therapy is available, there is an urgent need to understand all steps of the TBEV replication cycle at the molecular level. One of the critical events is the packaging of flaviviral genomic RNA by TBEV C protein to form a nucleocapsid. We purified recombinant TBEV C protein and used a combination of physical-chemical approaches, such as size-exclusion chromatography, circular dichroism, NMR spectroscopies, and transmission electron microscopy, to analyze its structural stability and its ability to dimerize/oligomerize. We compared the ability of TBEV C protein to assemble in vitro into a nucleocapsid-like structure with that of dengue C protein.
- MeSH
- cirkulární dichroismus MeSH
- gelová chromatografie MeSH
- koncentrace vodíkových iontů MeSH
- magnetická rezonanční spektroskopie MeSH
- nukleokapsida chemie metabolismus MeSH
- rekombinantní proteiny chemie genetika izolace a purifikace MeSH
- virové proteiny chemie genetika izolace a purifikace metabolismus MeSH
- virus dengue chemie MeSH
- viry klíšťové encefalitidy chemie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Bacterial MutM is a DNA repair glycosylase removing DNA damage generated from oxidative stress and, therefore, preventing mutations and genomic instability. MutM belongs to the Fpg/Nei family of prokaryotic enzymes sharing structural and functional similarities with their eukaryotic counterparts, for example, NEIL1-NEIL3. Here, we present two crystal structures of MutM from pathogenic Neisseria meningitidis: a MutM holoenzyme and MutM bound to DNA. The free enzyme exists in an open conformation, while upon binding to DNA, both the enzyme and DNA undergo substantial structural changes and domain rearrangement. Our data show that not only NEI glycosylases but also the MutMs undergo dramatic conformational changes. Moreover, crystallographic data support the previously published observations that MutM enzymes are rather flexible and dynamic molecules.
- MeSH
- bakteriální proteiny chemie metabolismus MeSH
- DNA bakterií chemie metabolismus MeSH
- DNA-formamidopyrimidinglykosylasa chemie metabolismus MeSH
- krystalografie rentgenová MeSH
- Neisseria meningitidis enzymologie MeSH
- proteinové domény MeSH
- vazba proteinů MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Gangliosides are glycosphingolipids consisting of a ceramide base and a bulky sugar chain that contains one or more sialic acids. This unique structure endows gangliosides with a strong tendency to self-aggregate in solution, as well as in cellular membranes, where they can form nanoscopic assemblies called ganglioside nanodomains. As gangliosides are important biological molecules involved in a number of physiological processes, characterization of their lateral organization in membranes is essential. This review aims at providing comprehensive information about the nanoscale organization of gangliosides in various synthetic models. To this end, the impact of the hydrophobic backbone and the headgroup on the segregation of gangliosides into nanodomains are discussed in detail, as well as the way in which the properties of nanodomains are affected by ligand binding. Small size makes the characterization of ganglioside nanodomains challenging, and we thus highlight the biophysical methods that have advanced this research, such as Monte Carlo Förster resonance energy transfer, atomic force microscopy and approaches based on molecular diffusion.
- MeSH
- buněčná membrána chemie MeSH
- gangliosidy chemie MeSH
- hydrofobní a hydrofilní interakce MeSH
- lidé MeSH
- ligandy MeSH
- lipidové dvojvrstvy chemie MeSH
- mikroskopie atomárních sil MeSH
- rezonanční přenos fluorescenční energie MeSH
- sacharidové sekvence MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
The HelD is a helicase-like protein binding to Bacillus subtilis RNA polymerase (RNAP), stimulating transcription in an ATP-dependent manner. Here, our small angle X-ray scattering data bring the first insights into the HelD structure: HelD is compact in shape and undergoes a conformational change upon substrate analog binding. Furthermore, the HelD domain structure is delineated, and a partial model of HelD is presented. In addition, the unique N-terminal domain of HelD is characterized as essential for its transcription-related function but not for ATPase activity, DNA binding, or binding to RNAP. The study provides a topological basis for further studies of the role of HelD in transcription.
- MeSH
- Bacillus subtilis enzymologie MeSH
- bakteriální proteiny chemie metabolismus MeSH
- difrakce rentgenového záření MeSH
- DNA řízené RNA-polymerasy metabolismus MeSH
- maloúhlový rozptyl MeSH
- molekulární modely MeSH
- proteinové domény MeSH
- vazba proteinů MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Ferric reductase B (FerB) is a flavin mononucleotide (FMN)-containing NAD(P)H:acceptor oxidoreductase structurally close to the Gluconacetobacter hansenii chromate reductase (ChrR). The crystal structure of ChrR was previously determined with a chloride bound proximal to FMN in the vicinity of Arg101, and the authors suggested that the anionic electron acceptors, chromate and uranyl tricarbonate, bind similarly. Here, we identify the corresponding arginine residue in FerB (Arg95) as being important for the reaction of FerB with superoxide. Four mutants at position 95 were prepared and found kinetically to have impaired capacity for superoxide binding. Stopped-flow data for the flavin cofactor showed that the oxidative step is rate limiting for catalytic turnover. The findings are consistent with a role for FerB as a superoxide scavenging contributor.
- MeSH
- arginin genetika MeSH
- flavinmononukleotid chemie genetika MeSH
- flaviny genetika metabolismus MeSH
- FMN-reduktasa chemie genetika MeSH
- katalytická doména genetika MeSH
- kinetika MeSH
- konformace proteinů * MeSH
- krystalografie rentgenová MeSH
- oxidace-redukce MeSH
- oxidoreduktasy chemie genetika MeSH
- Paracoccus denitrificans chemie enzymologie MeSH
- sekvence aminokyselin genetika MeSH
- superoxidy metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
In the model cyanobacterium Synechocystis sp. PCC 6803, the terminal enzyme of chlorophyll biosynthesis, chlorophyll synthase (ChlG), forms a complex with high light-inducible proteins, the photosystem II assembly factor Ycf39 and the YidC/Alb3/OxaI membrane insertase, co-ordinating chlorophyll delivery with cotranslational insertion of nascent photosystem polypeptides into the membrane. To gain insight into the ubiquity of this assembly complex in higher photosynthetic organisms, we produced functional foreign chlorophyll synthases in a cyanobacterial host. Synthesis of algal and plant chlorophyll synthases allowed deletion of the otherwise essential native cyanobacterial gene. Analysis of purified protein complexes shows that the interaction with YidC is maintained for both eukaryotic enzymes, indicating that a ChlG-YidC/Alb3 complex may be evolutionarily conserved in algae and plants.
- MeSH
- bakteriální proteiny genetika metabolismus MeSH
- fotosyntéza účinky záření MeSH
- fotosystém II - proteinový komplex genetika metabolismus MeSH
- fylogeneze MeSH
- ligasy tvořící vazby C-O klasifikace genetika metabolismus MeSH
- proteiny huseníčku genetika metabolismus MeSH
- světlo MeSH
- Synechocystis genetika metabolismus MeSH
- tylakoidy metabolismus účinky záření MeSH
- vazba proteinů účinky záření MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Conventional biophysical and chemical biology approaches for delineating relationships between the structure and biological function of nucleic acids (NAs) abstract NAs from their native biological context. However, cumulative experimental observations have revealed that the structure, dynamics and interactions of NAs might be strongly influenced by a broad spectrum of specific and nonspecific physical-chemical environmental factors. This consideration has recently sparked interest in the development of novel tools for structural characterization of NAs in the native cellular context. Here, we review the individual methods currently being employed for structural characterization of NA structure in a native cellular environment with a focus on recent advances and developments in the emerging fields of in-cell NMR and electron paramagnetic resonance spectroscopy and in-cell single-molecule FRET of NAs.
- MeSH
- analýza jednotlivých buněk MeSH
- buňky chemie MeSH
- elektronová paramagnetická rezonance MeSH
- konformace nukleové kyseliny MeSH
- lidé MeSH
- magnetická rezonanční spektroskopie MeSH
- molekulární modely MeSH
- nukleové kyseliny chemie metabolismus MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
