| 1. |
- Kmiec, Beata, et al.
(author)
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Organellar oligopeptidase (OOP) provides a complementary pathway for targeting peptide degradation in mitochondria and chloroplasts
- 2013
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In: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 110:40, s. E3761-E3769
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Journal article (peer-reviewed)abstract
- Both mitochondria and chloroplasts contain distinct proteolytic systems for precursor protein processing catalyzed by the mitochondrial and stromal processing peptidases and for the degradation of targeting peptides catalyzed by presequence protease. Here, we have identified and characterized a component of the organellar proteolytic systems in Arabidopsis thaliana, the organellar oligopeptidase, OOP (At5g65620). OOP belongs to the M3A family of peptide-degrading metalloproteases. Using two independent in vivo methods, we show that the protease is dually localized to mitochondria and chloroplasts. Furthermore, we localized the OPP homolog At5g10540 to the cytosol. Analysis of peptide degradation by OOP revealed substrate size restriction from 8 to 23 aa residues. Short mitochondrial targeting peptides (presequence of the ribosomal protein L29 and presequence of 1-aminocyclopropane-1-carboxylic acid deaminase 1) and N- and C-terminal fragments derived from the presequence of the ATPase beta subunit ranging in size from 11 to 20 aa could be degraded. MS analysis showed that OOP does not exhibit a strict cleavage pattern but shows a weak preference for hydrophobic residues (F/L) at the P1 position. The crystal structures of OOP, at 1.8-1.9 angstrom, exhibit an ellipsoidal shape consisting of two major domains enclosing the catalytic cavity of 3,000 angstrom(3). The structural and biochemical data suggest that the protein undergoes conformational changes to allow peptide binding and proteolysis. Our results demonstrate the complementary role of OOP in targeting-peptide degradation in mitochondria and chloroplasts.
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| 2. |
- Gad, Helge, et al.
(author)
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MTH1 inhibition eradicates cancer by preventing sanitation of the dNTP pool
- 2014
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In: Nature. - : Nature Publishing Group. - 0028-0836 .- 1476-4687. ; 508:7495, s. 215-221
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Journal article (peer-reviewed)abstract
- Cancers have dysfunctional redox regulation resulting in reactive oxygen species production, damaging both DNA and free dNTPs. The MTH1 protein sanitizes oxidized dNTP pools to prevent incorporation of damaged bases during DNA replication. Although MTH1 is non-essential in normal cells, we show that cancer cells require MTH1 activity to avoid incorporation of oxidized dNTPs, resulting in DNA damage and cell death. We validate MTH1 as an anticancer target in vivo and describe small molecules TH287 and TH588 as first-in-class nudix hydrolase family inhibitors that potently and selectively engage and inhibit the MTH1 protein in cells. Protein co-crystal structures demonstrate that the inhibitors bindin the active site of MTH1. The inhibitors cause incorporation of oxidized dNTPs in cancer cells, leading to DNA damage, cytotoxicity and therapeutic responses in patient-derived mouse xenografts. This study exemplifies the non-oncogene addiction concept for anticancer treatment and validates MTH1 as being cancer phenotypic lethal.
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| 3. |
- Plowright, Alleyn T., et al.
(author)
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Design and synthesis of a novel series of cyclohexyloxy-pyridyl derivatives as inhibitors of diacylglycerol acyl transferase 1
- 2013
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In: MedChemComm. - : Royal Society of Chemistry (RSC). - 2040-2503 .- 2040-2511. ; 4:1, s. 151-158
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Journal article (peer-reviewed)abstract
- A novel series of potent diacylglycerol acyl transferase 1 inhibitors was developed from the clinical candidate AZD3988. Replacement of the phenyl cyclohexyl-ethanoate side chain with substituted oxy-linked side chains to introduce changes in shape and polarity, reduce lipophilicity and mask the hydrogen bond donors with internal hydrogen bond acceptors led to improvements in solubility, unbound clearance and excellent selectivity over the related enzyme acyl-coenzyme A:cholesterol acyltransferase 1. A comparison of the small molecule crystal structures of compound 4 and compound 28 is described. Compounds in this series have good ADMET properties and provide an exposure-dependent decrease in circulating plasma triglyceride levels in a rat oral lipid tolerance test.
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| 4. |
- Berntsson, Ronnie P. -A., et al.
(author)
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Structural insight into DNA binding and oligomerization of the multifunctional Cox protein of bacteriophage P2
- 2014
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In: Nucleic Acids Research. - : Oxford University Press (OUP). - 0305-1048 .- 1362-4962. ; 42:4, s. 2725-2735
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Journal article (peer-reviewed)abstract
- The Cox protein from bacteriophage P2 is a small multifunctional DNA-binding protein. It is involved in site-specific recombination leading to P2 prophage excision and functions as a transcriptional repressor of the P2 Pc promoter. Furthermore, it transcriptionally activates the unrelated, defective prophage P4 that depends on phage P2 late gene products for lytic growth. In this article, we have investigated the structural determinants to understand how P2 Cox performs these different functions. We have solved the structure of P2 Cox to 2.4 angstrom resolution. Interestingly, P2 Cox crystallized in a continuous oligomeric spiral with its DNA-binding helix and wing positioned outwards. The extended C-terminal part of P2 Cox is largely responsible for the oligomerization in the structure. The spacing between the repeating DNA-binding elements along the helical P2 Cox filament is consistent with DNA binding along the filament. Functional analyses of alanine mutants in P2 Cox argue for the importance of key residues for protein function. We here present the first structure from the Cox protein family and, together with previous biochemical observations, propose that P2 Cox achieves its various functions by specific binding of DNA while wrapping the DNA around its helical oligomer.
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| 5. |
- Berntsson, Ronnie P., et al.
(author)
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Crystal Structures of Botulinum Neurotoxin DC in Complex with Its Protein Receptors Synaptotagmin I and II
- 2013
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In: Structure. - : Elsevier BV. - 0969-2126 .- 1878-4186. ; 21:9, s. 1602-1611
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Journal article (peer-reviewed)abstract
- Botulinum neurotoxins (BoNTs) can cause paralysis at exceptionally low concentrations and include seven serotypes (BoNT/A-G). The chimeric BoNT/DC toxin has a receptor binding domain similar to the same region in BoNT/C. However, BoNT/DC does not share protein receptor with BoNT/C. Instead, it shares synaptotagmin (Syt) I and II as receptors with BoNT/B, despite their low sequence similarity. Here, we present the crystal structures of the binding domain of BoNT/DC in complex with the recognition domains of its protein receptors, Syt-I and Syt-II. The structures reveal that BoNT/DC possesses a Syt binding site, distinct from the established Syt-II binding site in BoNT/B. Structure-based mutagenesis further shows that hydrophobic interactions play a key role in Syt binding. The structures suggest that the BoNT/DC ganglioside binding sites are independent of the protein receptor binding site. Our results reveal the remarkable versatility in the receptor recognition of the BoNTs.
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| 6. |
- Blaauw, M., et al.
(author)
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Were last glacial climate events simultaneous between Greenland and France?
- 2010
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In: Journal of Quaternary Science. - : Wiley. - 0267-8179 .- 1099-1417. ; 25:3, s. 387-394
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Journal article (peer-reviewed)abstract
- Several large abrupt climate fluctuations during the last glacial have been recorded in Greenland ice cores and archives from other regions. Often these Dansgaard–Oeschger events are assumed to have been synchronous over wide areas, and then used as tie-points to link chronologies between the proxy archives. However, it has not yet been tested independently whether or not these events were indeed synchronous over large areas. Here, we compare Dansgaard–Oeschger-type events in a well-dated record from southeastern France with those in Greenland ice cores. Instead of assuming simultaneous climate events between both archives, we keep their age models independent. Even these well-dated archives possess large chronological uncertainties that prevent us from inferring synchronous climate events at decadal to multi-centennial time scales. If possible, comparisons between proxy archives should be based on independent, non-tuned time-scales.
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| 7. |
- Boström, Pontus, 1982, et al.
(author)
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The SNARE protein SNAP23 and the SNARE-interacting protein Munc18c in human skeletal muscle are implicated in insulin resistance/type 2 diabetes.
- 2010
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In: Diabetes. - : American Diabetes Association. - 1939-327X .- 0012-1797. ; 59:8, s. 1870-8
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Journal article (peer-reviewed)abstract
- OBJECTIVE: Our previous studies suggest that the SNARE protein synaptosomal-associated protein of 23 kDa (SNAP23) is involved in the link between increased lipid levels and insulin resistance in cardiomyocytes. The objective was to determine whether SNAP23 may also be involved in the known association between lipid accumulation in skeletal muscle and insulin resistance/type 2 diabetes in humans, as well as to identify a potential regulator of SNAP23. RESEARCH DESIGN AND METHODS: We analyzed skeletal muscle biopsies from patients with type 2 diabetes and healthy, insulin-sensitive control subjects for expression (mRNA and protein) and intracellular localization (subcellular fractionation and immunohistochemistry) of SNAP23, and for expression of proteins known to interact with SNARE proteins. Insulin resistance was determined by a euglycemic hyperinsulinemic clamp. Potential mechanisms for regulation of SNAP23 were also investigated in the skeletal muscle cell line L6. RESULTS: We showed increased SNAP23 levels in skeletal muscle from patients with type 2 diabetes compared with that from lean control subjects. Moreover, SNAP23 was redistributed from the plasma membrane to the microsomal/cytosolic compartment in the patients with the type 2 diabetes. Expression of the SNARE-interacting protein Munc18c was higher in skeletal muscle from patients with type 2 diabetes. Studies in L6 cells showed that Munc18c promoted the expression of SNAP23. CONCLUSIONS: We have translated our previous in vitro results into humans by showing that there is a change in the distribution of SNAP23 to the interior of the cell in skeletal muscle from patients with type 2 diabetes. We also showed that Munc18c is a potential regulator of SNAP23.
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| 8. |
- Fossum, Mariann, et al.
(author)
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Effects of a computerized decision support system on care planning for pressure ulcers and malnutrition in nursing homes : an intervention study
- 2013
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In: International Journal of Medical Informatics. - : Elsevier BV. - 1386-5056 .- 1872-8243. ; 82:10, s. 911-921
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Journal article (peer-reviewed)abstract
- Background: Nursing documentation is essential for facilitating the flow of information to guarantee continuity, quality and safety in care. High-quality nursing documentation is frequently lacking; the implementation of computerized decision support systems is expected to improve clinical practice and nursing documentation.Aim: The present study aimed at investigate the effects of a computerized decision support system and an educational program as intervention strategies for improved nursing documentation practice on pressure ulcers and malnutrition in nursing homes.Design, setting and participants: An intervention study with two intervention groups and one control group was used. Fifteen nursing homes in southern Norway were included. A convenience sample of electronic healthcare records from 46 units was included. Inclusion criteria were records with presence of pressure ulcers and/or malnutrition. The residents were assessed before and after an intervention of a computerized decision support system in the electronic healthcare records. Data were collected through a review of 150 records before (2007) and 141 records after the intervention (2009).Methods: The nurses in intervention group 1 were offered educational sessions and were trained to use the computerized decision support system, which they used for eight months in 2008 and 2009. The nurses in intervention group 2 were offered the same educational program but did not use the computerized decision support system. The nurses in the control group were not subject to any intervention. The resident records were examined for the completeness and comprehensiveness of the documentation of pressure ulcers and malnutrition with three data collection forms and the data were analyzed with non-parametric statistics.Results: The implementation of the computerized decision support system and the educational program resulted in a more complete and comprehensive documentation of pressure ulcer- and malnutrition-related nursing assessments and nursing interventions.Conclusion: This study provides evidence that the computerized decision support system and an educational program as implementation strategies had a positive influence on nursing documentation practice.
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| 9. |
- Ingemarsson, Linda, 1972, et al.
(author)
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Oxidation behavior at 300–1000C of a (Mo,W)Si2-based composite containing boride
- 2010
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In: Intermetallics. - : Elsevier BV. - 0966-9795. ; 18:1, s. 77-86
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Journal article (peer-reviewed)abstract
- The oxidation behavior of a (Mo,W)Si2 composite with boride addition was examined at 300–1000C for24 h in dry O2. The oxidation kinetics was studied using a thermobalance, and the oxide scales wereanalyzed using a combination of electron microscopy (SEM/EDX, FIB, BIB) and XRD. Accelerated oxidationwas found to occur between 500C and 675C, with a peak mass gain at 625C. The rapid oxidation isattributed to the vaporization of molybdenum oxide that leaves a porous and poorly protective silicalayer behind. At higher temperature (700–1000C) a protective scale forms, consisting of a dense SiO2/B2O3 glass.
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| 10. |
- Ingemarsson, Linda, 1972, et al.
(author)
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Oxidation behavior of a Mo (Si, Al)(2)-based composite at 300-1000 degrees C
- 2010
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In: Intermetallics. - : Elsevier BV. - 0966-9795 .- 1879-0216. ; 18:4, s. 633-640
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Journal article (peer-reviewed)abstract
- The oxidation behavior of a Mo (Si,Al)(2)-based composite of Mo(Si,Al)(2), Al2O3 and Mo-5(Si,Al)(3) (Kanthal Super ER) in synthetic air was investigated. The samples were oxidized isothermally for up to 72 h at 300-1000 degrees C using a thermobalance. The microstructure was analyzed by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Auger Electron Spectroscopy (AES) depth profiling. Broad ion beam milling (BIB) was used to prepare cross-sections. Oxidation behavior depended strongly on the composition of the substrate which consisted of a Mo(Si,Al)(2) matrix and the minority phases Mo-5(Si,Al)(3) and Al2O3. At 300-500 degrees C the mass gains were small with parabolic kinetics, oxidation resulting in a mixture of oxides that reflects the substrate composition. At 600 and 700 degrees C the oxide scale is thin and protective and depleted in molybdenum, a mass loss occurring due to MoO3 vaporization. At 1000 degrees C a protective alpha-alumina scale forms.
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