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Berlin Brandenburg

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  • 1
    Language: English
    In: Biochemistry, 06 April 2010, Vol.49(13), pp.2805-10
    Description: Identification of diseases caused by protein misfolding has increased interest in the way proteins adopt non-native conformations and form aggregates. In this study we address the question of how proteins sharing the same fold respond to destabilizing environmental conditions. We have studied the behavior of two members of the cystatin superfamily, MNEI, a single chain monellin, and oryzacystatin_I, a plant cystatin. Despite the close similarity of their three-dimensional architecture, these two proteins aggregate in a different way: MNEI gives rise to amyloid aggregation whereas oryzacystatin_I yields amorphous aggregates. Mutants of oryzacystatin_I, designed to make it more similar to MNEI, generally behave like the parent protein, but a construct devoid of the disordered N- and C-terminal sequences does show a tendency to form amyloid fibers. Our results suggest that precise sequence details may be more important than the three-dimensional architecture in determining the type of aggregate formed. Oryzacystatin_I appears to be a very promising model system for further studies of protein aggregation.
    Keywords: Protein Multimerization ; Cystatins -- Chemistry ; Plant Proteins -- Chemistry
    ISSN: 00062960
    E-ISSN: 1520-4995
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  • 2
    Language: English
    In: BBA - General Subjects, April 2016, Vol.1860(4), pp.795-801
    Description: About twenty variants of apolipoprotein A-I (ApoA-I) are associated to hereditary systemic amyloidoses. Although the molecular bases of this disease are still largely unknown, it has been hypothesized that ApoA-I proteolysis is a key event in pathogenesis, since it triggers the release of an N-terminal fragment (80–100 residue long) that misfolds to form amyloid deposits in peripheral organs and tissues. It is also known that cell membrane lipids play a key role in the fibrillogenic pathway. In the case of ApoA-I related amyloidosis caused by L174S mutation, the 93-residue N-terminal fragment of ApoA-I ([1-93]ApoA-I) was found to be the major constituent of fibrils. With the main goal to investigate the interaction of either [1-93]ApoA-I and ApoA-I with biomimetic membranes, we set-up an experimental system based on the Raman Tweezers methodology. We tested GUVs composed by two types of zwitterionic lipids with a different fluidity degree, dioleoylphosphatidylcholine (DOPC) and dipalmitoylphosphatidylcholine (DPPC). We found that [1-93]ApoA-I induces conformational disorder in an ordered lipid bilayer. When interacting with fluid phases, instead, the fragment was found to be able to penetrate the membrane bilayer inducing an alignment of lipid chains. The interaction features of [1-93]ApoA-I with biomimetic membranes strongly depend on the lipid phase. Full-length ApoA-I was found to have similar effects, even if significantly less pronounced. Our observations shed light on still largely unknown molecular bases of ApoA-I fibrillogenic domain interaction with membranes.
    Keywords: Amyloidosis ; Raman Tweezers ; Apoa-I ; Model Membranes ; Lipid Phases ; Biology ; Chemistry
    ISSN: 0304-4165
    E-ISSN: 1872-8006
    E-ISSN: 18782434
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  • 3
    Language: English
    In: Biotechnology Letters, 2011, Vol.33(1), pp.159-165
    Description: Several transgenic tobacco lines expressing human apolipoprotein A-I (ApoA-I) were obtained. Western blot analyses indicated the expression of the recombinant protein in plant organs at various stages of development, including senescent leaves. A cell line expressing human ApoA-I was established from a T 1 transgenic plant. Recombinant ApoA-I was isolated either from extracts of transgenic leaves and from the culture medium of transgenic cells using an antibody-based one-step procedure.
    Keywords: Apolipoprotein A-I ; Molecular farming ; Nicotiana tabacum ; Plant cell culture ; Transgenic plant
    ISSN: 0141-5492
    E-ISSN: 1573-6776
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  • 4
    Language: English
    In: Biotechnology Letters, 2013, Vol.35(6), pp.983-983
    Description: Byline: Pasquale Chiaiese (1), Maria Minutolo (1), Angela Arciello (2,3), Fulvio Guglielmi (2), Renata Piccoli (2,3), Edgardo Filippone (1) Author Affiliation: (1) Department of Soil, Plant, Environmental and Animal Production Sciences, School of Biotechnological Sciences, University of Naples Federico II, Naples, Italy (2) Department of Structural and Functional Biology, School of Biotechnological Sciences, University of Naples Federico II, Complesso Universitario di Monte S. Angelo Via Cinthia 4, 80126, Naples, Italy (3) Istituto Nazionale di Biostrutture e Biosistemi (INBB), Rome, Italy Article History: Registration Date: 11/10/2010 Online Date: 22/10/2010 Article note: Pasquale Chiaiese, Maria Minutolo contributed equally to this work. The online version of the original article can be found under doi: 10.1007/s10529-010-0388-4. The online version of the original article can be found at http://dx.doi.org/10.1007/s10529-010-0388-4.
    Keywords: Engineering ; Biology;
    ISSN: 0141-5492
    E-ISSN: 1573-6776
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  • 5
    In: Metallomics, 2014, Vol.6(3), pp.587-597
    Description: Heavy metals are extremely poisonous to the environment, but their impact on living cells and organisms is poorly understood at a molecular level. We investigated the effects of cadmium and lead on the viability of primary HRCE cells. A severe dose- and time-dependent inhibition of cell viability was induced by either heavy metal. Cell mortality was due to apoptotic death, as demonstrated by a decrease of procaspase-9 and down-regulation of the anti-apoptotic marker Bcl-2 with consequent activation of caspase-3. By ICP-MS analyses we determined the amount of heavy metals in the intracellular compartment, which was found to be higher for lead than cadmium. To gain insights into the effects of heavy metals on the cell proteome, a systematic investigation was performed, based on 2D-PAGE, image analysis, protein identification and bioinformatics analyses. Among more than 300 protein spots visualized in bidimensional maps, 27 proteins were found to be altered in their expression levels following heavy metal exposure. These proteins were all identified by nanoLC-MS/MS. The majority of them were found to be involved in apoptotic pathways, protein folding or energetic metabolism, which eventually lead to cell death. Taking advantage of an integrated workflow, we identified specific protein targets of heavy metals, which represent a contribution to the identification of potential biomarkers of heavy metal environmental pollution.
    Keywords: Cadmium -- Metabolism ; Environmental Pollutants -- Metabolism ; Kidney -- Cytology ; Lead -- Metabolism ; Proteome -- Metabolism;
    ISSN: 1756-5901
    E-ISSN: 1756-591X
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  • 6
    Language: English
    In: Cellular and Molecular Life Sciences, 2016, Vol.73(3), pp.637-648
    Description: A hallmark to decipher bioprocesses is to characterize protein–protein interactions in living cells. To do this, the development of innovative methodologies, which do not alter proteins and their natural environment, is particularly needed. Here, we report a method (LUCK, Laser UV Cross-linKing) to in vivo cross-link proteins by UV-laser irradiation of living cells. Upon irradiation of HeLa cells under controlled conditions, cross-linked products of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) were detected, whose yield was found to be a linear function of the total irradiation energy. We demonstrated that stable dimers of GAPDH were formed through intersubunit cross-linking, as also observed when the pure protein was irradiated by UV-laser in vitro. We proposed a defined patch of aromatic residues located at the enzyme subunit interface as the cross-linking sites involved in dimer formation. Hence, by this technique, UV-laser is able to photofix protein surfaces that come in direct contact. Due to the ultra-short time scale of UV-laser-induced cross-linking, this technique could be extended to weld even transient protein interactions in their native context.
    Keywords: Protein–protein interactions ; Ultra-short UV-laser pulses ; UV cross-linking ; Living cells irradiation
    ISSN: 1420-682X
    E-ISSN: 1420-9071
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  • 7
    Language: English
    In: BBA - General Subjects, February 2016, Vol.1860(2), pp.434-444
    Description: Amyloidoses are devastating diseases characterized by accumulation of misfolded proteins which aggregate in fibrils. Specific gene mutations in Apolipoprotein A I (ApoAI) are associated with systemic amyloidoses. Little is known on the effect of mutations on ApoAI structure and amyloid properties. Here we performed a physico-chemical characterization of L75P- and L174S-amyloidogenic ApoAI (AApoAI) variants to shed light on the effects of two single point mutations on protein stability, proteolytic susceptibility and aggregation propensity. Both variants are destabilized in their N-terminal region and generate fibrils with different morphological features. L75P-AApoAI is significantly altered in its conformation and compactness, whereas a more flexible and pronounced aggregation-competent state is associated to L174S-AApoAI. These observations point out how single point mutations in ApoAI gene evocate differences in the physico-chemical and conformational behavior of the corresponding protein variants, with the common feature of diverting ApoAI from its natural role towards a pathogenic pathway.
    Keywords: Apolipoprotein A I ; Protein Stability ; Amyloidosis ; Conformational Diseases ; Biology ; Chemistry
    ISSN: 0304-4165
    E-ISSN: 1872-8006
    E-ISSN: 18782434
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  • 8
    Language: English
    In: Proceedings of the National Academy of Sciences of the United States of America, 14 April 1998, Vol.95(8), pp.4579-4583
    Description: Angiogenin (Ang), an inducer of neovascularization, is secreted by several types of human tumor cells and appears critical for their growth. The murine anti-Ang monoclonal antibody (mAb) 26-2F neutralizes the activities of Ang and dramatically prevents the establishment and metastatic dissemination of human tumor cell xenografts in athymic mice. However, for use clinically, the well-documented problem of the human anti-globulin antibody response known to occur with murine antibodies requires resolution. As a result, chimeric as well as totally humanized antibodies are currently being evaluated as therapeutic agents for the treatment of several pathological conditions, including malignancy. Therefore, we have constructed a chimeric mouse/human antibody based on the structure of mAb 26-2F. Complementary DNAs from the light and heavy chain variable regions of mAb 26-2F were cloned, sequenced, and genetically engineered by PCR for subcloning into expression vectors that contain human constant region sequences. Transfection of these vectors into nonproducing mouse myeloma cells resulted in the secretion of fully assembled tetrameric molecules. The chimeric antibody (cAb 26-2F) binds to Ang and inhibits its ribonucleolytic and angiogenic activities as potently as mAb 26-2F. Furthermore, the capacities of cAb 26-2F and its murine counterpart to suppress the formation of human breast cancer tumors in athymic mice are indistinguishable. Thus cAb 26-2F, with its retained neutralization capability and likely decreased immunogenicity, may be of use clinically for the treatment of human cancer and related disorders where pathological angiogenesis is a component.
    Keywords: Health sciences -- Medical sciences -- Immunology ; Physical sciences -- Chemistry -- Chemical compounds ; Health sciences -- Medical conditions -- Diseases ; Biological sciences -- Biology -- Zoology ; Biological sciences -- Biology -- Cytology ; Biological sciences -- Biology -- Genetics ; Applied sciences -- Materials science -- Materials ; Biological sciences -- Biology -- Cytology ; Applied sciences -- Laboratory techniques -- Nucleic acid amplification techniques ; Biological sciences -- Biology -- Genetics
    ISSN: 00278424
    E-ISSN: 10916490
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  • 9
    Language: English
    In: Proceedings of the National Academy of Sciences of the United States of America, 01 March 1992, Vol.89(5), pp.1870-1874
    Description: Bovine seminal ribonuclease, the only dimeric ribonuclease described thus far, is found to exist in two different quaternary structure forms. In one, the N-terminal segment (residues 1-17) of each subunit is interchanged with the remaining segment of the other subunit, whereas in the second, such interchange does not occur. Functionally, they differ in that the catalytic activity of the form with interchange can be modulated by the substrate, whereas the noninterchange form exhibits no cooperativity. Each form can convert into the other, up to an equilibrium ratio, which is that found for the isolated protein. The results of refolding experiments of unfolded protein chains suggest that also in vivo the form lacking interchange may be produced first and is then partially transformed into the other dimeric form until equilibrium is reached. Although the implications of these findings may not be immediately apparent, they are intriguing and may have an impact on the unusual noncatalytic actions of the protein, such as its selective cytotoxicity toward tumor cells, activated T cells, and differentiated male germ cells.
    Keywords: Physical sciences -- Chemistry -- Chemical compounds ; Physical sciences -- Chemistry -- Chemical compounds ; Physical sciences -- Chemistry -- Chemical compounds ; Physical sciences -- Physics -- Microphysics ; Applied sciences -- Materials science -- Materials ; Philosophy -- Metaphysics -- Ontology ; Physical sciences -- Chemistry -- Chemical compounds ; Biological sciences -- Biochemistry -- Enzymology ; Physical sciences -- Chemistry -- Chemical reactions ; Biological sciences -- Biology -- Cytology
    ISSN: 00278424
    E-ISSN: 10916490
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  • 10
    Language: English
    In: Journal of molecular biology, 01 April 2011, Vol.407(3), pp.465-76
    Description: The 93-residue N-terminal fragment of apolipoprotein A-I (ApoA-I) is the major constituent of fibrils isolated from patients affected by the amyloidosis caused by ApoA-I mutations. We have prepared eight polypeptides corresponding to all the currently known amyloidogenic variants of the N-terminal region of ApoA-I, other than a truncation mutation, and investigated their aggregation kinetics and the associated structural modifications. All the variants adopted a monomeric highly disordered structure in solution at neutral pH, whereas acidification of the solution induced an unstable α-helical conformation and the subsequent aggregation into the cross-β structure aggregate. Two mutations (Δ70-72 and L90P) almost abrogated the lag phase of the aggregation process, three mutations (Δ60-71, L75P, and W50R) significantly accelerated the aggregation rate by 2- to 3-fold, while the remaining three variants (L64P, L60R, and G26R) were not significantly different from the wild type. Therefore, an increase in aggregation propensity cannot explain per se the mechanism of the disease for all the variants. Prediction of the protection factors for hydrogen exchange in the native state of full-length protein reveals, in almost all the variants, an expansion of the conformational fluctuations that could favour the proteolytic cleavage and the release of the amyloidogenic peptide. Such an event seems to be a necessary prerequisite for ApoA-I fibrillogenesis in vivo, but the observed increased aggregation propensity of certain variants can have a strong influence on the severity of the disease, such as an earlier onset and a faster progression.
    Keywords: Mutation ; Amyloid -- Metabolism ; Apolipoprotein A-I -- Genetics
    ISSN: 00222836
    E-ISSN: 1089-8638
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