Search results for " Structural Biology"
showing 10 items of 21 documents
Encapsulation mechanisms and structural studies of GRM2 bacterial microcompartment particles
2019
Bacterial microcompartments (BMCs) are prokaryotic organelles consisting of a protein shell and an encapsulated enzymatic core. BMCs are involved in several biochemical processes, such as choline, glycerol and ethanolamine degradation and carbon fixation. Since non-native enzymes can also be encapsulated in BMCs, an improved understanding of BMC shell assembly and encapsulation processes could be useful for synthetic biology applications. Here we report the isolation and recombinant expression of BMC structural genes from the Klebsiella pneumoniae GRM2 locus, the investigation of mechanisms behind encapsulation of the core enzymes, and the characterization of shell particles by cryo-EM. We …
Recombinant mussel protein Pvfp-5β: A potential tissue bioadhesive
2019
During their lifecycle, many marine organisms rely on natural adhesives to attach to wet surfaces for movement and self-defence in aqueous tidal environments. Adhesive proteins from mussels are biocompatible and elicit only minimal immune responses in humans. Therefore these proteins have received increased attention for their potential applications in medicine, biomaterials and biotechnology. The Asian green mussel Perna viridis secretes several byssal plaque proteins, molecules that help anchor the mussel to surfaces. Among these proteins, protein-5β (Pvfp-5β) initiates interactions with the substrate, displacing interfacial water molecules before binding to the surface. Here, we establis…
Analysis of the structural quality of the CASD-NMR 2013 entries
2015
We performed a comprehensive structure validation of both automated and manually generated structures of the 10 targets of the CASD-NMR-2013 effort. We established that automated structure determination protocols are capable of reliably producing structures of comparable accuracy and quality to those generated by a skilled researcher, at least for small, single domain proteins such as the ten targets tested. The most robust results appear to be obtained when NOESY peak lists are used either as the primary input data or to augment chemical shift data without the need to manually filter such lists. A detailed analysis of the long-range NOE restraints generated by the different programs from t…
Modulating carbohydrate-based hydrogels as viscoelastic lubricant substitute for articular cartilages
2017
Viscosupplementation is a therapeutic approach for osteoarthritis treatment, where the synovial fluid, the natural lubricant of the joints, is replaced by viscoelastic solutions with rheological properties comparable or better than the starting material. This study presents the development of an innovative platform for viscosupplementation, based on the optimization of polysaccharide-based colloidal hydrogel, aiming to reduce on-site enzyme degradation and enhance the possibility of hyaluronic acid substitution with alternative biomaterials. Catanionic vesicles are proposed as physical crosslinker that can guarantee the formation of a 'soft', tunable network, offering a dual-therapeutic app…
Halogen-bonded solvates of tetrahaloethynyl cavitands
2017
The formation and structures of halogen-bonded solvates of three different tetrahaloethynyl cavitands with acetone, chloroform, acetonitrile, DMF and DMSO were prepared and investigated. The inclusion and host–guest behaviour of the resorcinarene cavitands was found to be highly dependent on the flexibility of the ethylene-bridging unit.
Comparative analysis of two paradigm bacteriophytochromes reveals opposite functionalities in two-component signaling
2021
Bacterial phytochrome photoreceptors usually belong to two-component signaling systems which transmit environmental stimuli to a response regulator through a histidine kinase domain. Phytochromes switch between red light-absorbing and far-red light-absorbing states. Despite exhibiting extensive structural responses during this transition, the model bacteriophytochrome from Deinococcus radiodurans (DrBphP) lacks detectable kinase activity. Here, we resolve this long-standing conundrum by comparatively analyzing the interactions and output activities of DrBphP and a bacteriophytochrome from Agrobacterium fabrum (Agp1). Whereas Agp1 acts as a conventional histidine kinase, we identify DrBphP a…
Large-Scale Recombinant Production of the SARS-CoV-2 Proteome for High-Throughput and Structural Biology Applications
2021
The highly infectious disease COVID-19 caused by the Betacoronavirus SARS-CoV-2 poses a severe threat to humanity and demands the redirection of scientific efforts and criteria to organized research projects. The international COVID19-NMR consortium seeks to provide such new approaches by gathering scientific expertise worldwide. In particular, making available viral proteins and RNAs will pave the way to understanding the SARS-CoV-2 molecular components in detail. The research in COVID19-NMR and the resources provided through the consortium are fully disclosed to accelerate access and exploitation. NMR investigations of the viral molecular components are designated to provide the essential…
Direct observation of frequency modulated transcription in single cells using light activation
2013
Single-cell analysis has revealed that transcription is dynamic and stochastic, but tools are lacking that can determine the mechanism operating at a single gene. Here we utilize single-molecule observations of RNA in fixed and living cells to develop a single-cell model of steroid-receptor mediated gene activation. We determine that steroids drive mRNA synthesis by frequency modulation of transcription. This digital behavior in single cells gives rise to the well-known analog dose response across the population. To test this model, we developed a light-activation technology to turn on a single steroid-responsive gene and follow dynamic synthesis of RNA from the activated locus. DOI: http:/…
Induction of the peroxisome proliferator activated receptor by fenofibrate in rat liver
1992
AbstractThe process of peroxisome proliferation in rodent liver by hypolipidemic compounds and related substances has recently been shown to be receptor-madiated. In the present study, we have examined the effect of oral administration of the strong peroxisome proliferator fenofibrate on the hepatic expression level of the peroxisome proliferator activated receptor (PPAR) in rats. Immunoblots of rat liver cytosols and nuclear extracs using antibodies raised against recombinant PPAR/β-galactosidase fusion proteins revealed a pronounced increase in the amount of PPAR protein in response to fenofibrate treatment. This induction could also be confirmed at the level or RNA by Northern blotting. …
An impaired peroxisomal targeting sequence leading to an unusual bicompartmental distribution of cytosolic epoxide hydrolase
1991
AbstractTo gain an understanding of the mechanism by which the subcellular distribution of cytosolic epoxide hydrolase (cEH) is directed, we have analyzed the carboxy terminal region of rat liver cEH by means of cDNA cloning to define the structure of its possible peroxisomal targeting sequence (PTS). Purified cEH was subjected to peptide analysis following endoproteinase Glu-C digestion and HPLC-separation of the fragments. The obtained sequence information was used to perform PCR experiments resulting in the isolation of a 680 bp cDNA clone encoding the carboxy terminus of cEH. The deduced amino acid sequence displays a terminal tripeptide Ser-Lys-Ile which is highly homologous to the PTS…