429 research outputs found

    “Exploring the Basement of Social Justice Issues”: A Graduate Upon Graduation

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    Photograph of rides building up, taken J. Stevens' Fair, 20 June 1961 whole general view, looking West. See Leeson's notebook 9, pages 92-95 for notes

    Three-Dimensional Solution Structure of Saccharomyces cerevisiae Reduced Iso-l-cytochromec

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    Two-dimensional ^1H NMR spectra of Saccharomyces cerevisiae reduced iso-1-cytochrome c have been used to confirm and slightly extend the assignment available in the literature. 1702 NOESY cross-peaks have been assigned, and their intensities have been measured. Through the program DIANA and related protocols (Güntert, 1992), a solution structure has been obtained by using 1442 meaningful NOEs and 13 hydrogen-bond constraints. The RMSD values with respect to the mean structure for the backbone and all heavy atoms for a family of 20 structures are 0.61 ± 0.09 and 0.98 ± 0.09 Å, the average target function value being as small as 0.57 Å^2. The larger number of slowly exchanging amide NHs observed in this system compared to that observed in the cyanide derivative of oxidized Ala 80 cytochrome c suggests that the oxidized form is much more flexible and that the backbone protons are more solvent accessible. Comparison of the present structure with the crystal structures of reduced yeast cytochrome c and of the complex between cytochrome c peroxidase and oxidized yeast cytochrome c reveals substantial similarity among the backbone conformations but differences in the residues located in the region of protein−protein interaction. Interestingly, in solution the peripheral residues involved in the interaction with cytochrome c peroxidase are on average closer to the position found in the crystal structure of the complex than to the solid state structure of the isolated reduced form

    Investigations of heme distortion, low-frequency vibrational excitations, and electron transfer in cytochrome c

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    Cytochrome (cyt) c is an important electron transfer protein. The ruffling deformation of its heme cofactor has been suggested to relate to its electron transfer rate. However, there is no direct experimental evidence demonstrating this correlation. In this work, we studied Pseudomonas aeruginosa cytochrome c551 and its F7A mutant. These two proteins, although similar in their X-ray crystal structure, display a significant difference in their heme outof- plane deformations, mainly along the ruffling coordinate. Resonance Raman and vibrational coherence measurements also indicate significant differences in ruffling-sensitive modes, particularly the low-frequency γa mode found between ~50-60 cm-1. This supports previous assignments of γa as having a large ruffling content. Measurement of the photoreduction kinetics finds an order of magnitude decrease of the photoreduction cross-section in the F7A mutant, which has nearly twice the ruffling deformation as the WT. Additional measurements on cytochrome c demonstrate that heme ruffling is correlated exponentially with the electron transfer rates and suggest that ruffling could play an important role in redox control. A major relaxation of heme ruffling in cytochrome c, upon binding to the mitochondrial membrane, is discussed in this context

    Heat-induced alterations in cashew allergen solubility and IgE binding

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    AbstractCashew nuts are an increasingly common cause of food allergy. We compare the soluble protein profile of cashew nuts following heating. SDS-PAGE indicate that heating can alter the solubility of cashew nut proteins. The 11S legumin, Ana o 2, dominates the soluble protein content in ready to eat and mildly heated cashew nuts. However, we found that in dark-roasted cashew nuts, the soluble protein profile shifts and the 2S albumin Ana o 3 composes up to 40% of the soluble protein. Analysis of trypsin-treated extracts by LC/MS/MS indicate changes in the relative number and intensity of peptides. The relative cumulative intensity of the 5 most commonly observed Ana o 1 and 2 peptides are altered by heating, while those of the 5 most commonly observed Ana o 3 peptides remaine relatively constant. ELISA experiments indicate that there is a decrease in rabbit IgG and human serum IgE binding to soluble cashew proteins following heating. Our findings indicate that heating can alter the solubility of cashew allergens, resulting in altered IgE binding. Our results support the use of both Ana o 2 and Ana o 3 as potential cashew allergen diagnostic targets

    Cyanoprokaryota of the Salt Marshes at the Pryazov National Natural Park, Ukraine

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    Cyanoprokaryota of salt marshes were investigated at three scientific sites: in the upper Utlyuk Estuary, on the coast of Lake Sivashik, and at Fedotov Spit. Data on species composition, systematic structure, leading families, and genera are provided. In total, 71 species of cyanoprokaryotes representing 3 orders, 10 families, and 22 genera. The dominant complex included representatives of the genera Schizothrix Kützing ex Gomont, Phormidium Kützing ex Gomont, Lyngbya C.Agardh ex Gomont, Leptolyngbya (Gomont) Anagnostidis & Komárek, Trichormus (Ralfs ex Bornet & Flahault) Komárek & Anagnostidis, Nostoc Vaucher ex Bornet & Flahault, and Nodularia Mert. ex Born. & Flah. The identified species are analyzed for their biotopic nature and their valence to the level of environmental salinity. The distribution of the identified species within the Ukrainian territory is considered

    Heme-protein vibrational couplings in cytochrome c provide a dynamic link that connects the heme-iron and the protein surface

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    The active site of cytochrome c (Cyt c) consists of a heme covalently linked to a pentapeptide segment (Cys-X-X-Cys-His), which provides a link between the heme and the protein surface, where the redox partners of Cyt c bind. To elucidate the vibrational properties of heme c, nuclear resonance vibrational spectroscopy (NRVS) measurements were performed on 57Fe-labeled ferric Hydrogenobacter thermophilus cytochrome c 552, including 13C8-heme-, 13C 515N-Met-, and 13C15N-polypeptide (pp)-labeled samples, revealing heme-based vibrational modes in the 200- to 450-cm-1 spectral region. Simulations of the NRVS spectra of H. thermophilus cytochrome c552 allowed for a complete assignment of the Fe vibrational spectrum of the protein-bound heme, as well as the quantitative determination of the amount of mixing between local heme vibrations and pp modes from the Cys-X-XCys-His motif. These results provide the basis to propose that heme-pp vibrational dynamic couplings play a role in electron transfer (ET) by coupling vibrations of the heme directly to vibrations of the pp at the protein - protein interface. This could allow for the direct transduction of the thermal (vibrational) energy from the protein surface to the heme that is released on protein/protein complex formation, or it could modulate the heme vibrations in the protein/protein complex to minimize reorganization energy. Both mechanisms lower energy barriers for ET. Notably, the conformation of the distal Met side chain is fine-tuned in the protein to localize heme-pp mixed vibrations within the 250-to 400-cm-1 spectral region. These findings point to a particular orientation of the distal Met that maximizes ET

    Cyanoprocaryota of Tubalskyi Estuary (Azov sea basin)

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    Information about species composition of Cyanoprocaryota representatives in the natural boundary of Tubalskyi Estuary within Pryazov National Natural Park is supplemented. Taxonomic structure of identified algae species is given, the data about occurrence of species in different habitats within national park is provided. We present a systematic structure and geographical affinity of discovered algae species. We registered 38 species of cyanoprocaryotic algae of orders: Chroococcales, Oscillatoriales and Nostocales with predominance of Oscillatoriales representatives in different habitats of Tubalskyi Estuary within the areas of Pryazov National Natural Park. The greatest number of algae species had genera Lyngbya, Phormidium, Microcoleus Leptolyngbya – 4 species per each genera. The majority of algae species were the cosmopolitans. Microcoleus tenerrimus was registered in all the studied plots of soil sampling and in the water reservoir of Tubalskyi Estuary. The most abundant and distributed species was Lyngbya aestuarii, which formed the macroscopic growths (cyanobacterial mats)
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