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91.
Pallabi De Shuying Zhao Lori M Gwyn LeAnn J Godderz Mandy M Peak Karla K Rodgers 《BMC biochemistry》2008,9(1):5
Background
Functional immunoglobulin and T cell receptor genes are produced in developing lymphocytes by V(D)J recombination. The initial site-specific DNA cleavage steps in this process are catalyzed by the V(D)J recombinase, consisting of RAG1 and RAG2, which is directed to appropriate DNA cleavage sites by recognition of the conserved recombination signal sequence (RSS). RAG1 contains both the active site and the RSS binding domains, although RAG2 is also required for DNA cleavage activity. An understanding of the physicochemical properties of the RAG proteins, their association, and their interaction with the RSS is not yet well developed. 相似文献92.
Tang J Jofre AM Lowman GM Kishore RB Reiner JE Helmerson K Goldner LS Greene ME 《Langmuir : the ACS journal of surfaces and colloids》2008,24(9):4975-4978
We inertially inject and study the contents of optically trappable aqueous nanodroplets (hydrosomes) emulsified in a perfluorinated matrix. A new piezoelectric actuated device for production of single hydrosomes on demand is introduced. Hydrosomes containing enhanced green fluorescent protein (EGFP) were injected, optically trapped, and held at the focus of an excitation laser in a confocal microscope, and single-molecule photobleaching events were observed. The rotational diffusion time of EGFP in trapped hydrosomes was measured using time-resolved fluorescence anisotropy. In free solution, the mean rotational diffusion time was determined to be 13.8 +/- 0.1 ns at 3 microM and 14.0 +/- 0.2 ns at 10 microM. In hydrosomes, the mean rotational diffusion time was similar and determined to be 12.6 +/- 1.0 ns at 3 microM and 15.5 +/- 1.6 ns at 10 microM. We conclude that the rotational motion inside the nanodroplets is consistent with rotation in free solution and that the protein therefore does not aggregate at the water-oil interface. Protein can be confined in hydrosomes with high efficiency using this technique, which provides an alternative to surface attachment or lipid encapsulation and opens up new avenues of research using single molecules contained in fluid nanovolumes. 相似文献
93.
Jessome L Hsu NY Wang YS Chen CH 《Rapid communications in mass spectrometry : RCM》2008,22(2):130-134
Desorption and ionization efficiencies of matrix-assisted laser desorption/ionization (MALDI) for various biomolecules with different dihydroxybenzoic acid isomers were studied. No clear relationships were observed between MALDI biomolecule signals vs. gas-phase basicity, proton affinity and ionization potential. This indicates the the gas-phase protonation mechanism is not adequate to explain the observed results. 相似文献
94.
Sanders LK Guáqueta C Angelini TE Lee JW Slimmer SC Luijten E Wong GC 《Physical review letters》2005,95(10):108302
Interactions between actin, an anionic polyelectrolyte, and lysozyme, a cationic globular protein, have been examined using a combination of synchrotron small-angle x-ray scattering and molecular dynamics simulations. Lysozyme initially bridges pairs of actin filaments, which relax into hexagonally coordinated columnar complexes comprised of actin held together by incommensurate one-dimensional close-packed arrays of lysozyme macroions. These complexes are found to be stable even in the presence of significant concentrations of monovalent salt, which is quantitatively explained from a redistribution of salt between the condensed and the aqueous phases. 相似文献
95.
Mucha M Frigato T Levering LM Allen HC Tobias DJ Dang LX Jungwirth P 《The journal of physical chemistry. B》2005,109(16):7617-7623
The molecular structure of the interfacial regions of aqueous electrolytes is poorly understood, despite its crucial importance in many biological, technological, and atmospheric processes. A long-term controversy pertains between the standard picture of an ion-free surface layer and the strongly ion specific behavior indicating in many cases significant propensities of simple inorganic ions for the interface. Here, we present a unified and consistent view of the structure of the air/solution interface of aqueous electrolytes containing monovalent inorganic ions. Molecular dynamics calculations show that in salt solutions and bases the positively charged ions, such as alkali cations, are repelled from the interface, whereas the anions, such as halides or hydroxide, exhibit a varying surface propensity, correlated primarily with the ion polarizability and size. The behavior of acids is different due to a significant propensity of hydronium cations for the air/solution interface. Therefore, both cations and anions exhibit enhanced concentrations at the surface and, consequently, these acids (unlike bases and salts) reduce the surface tension of water. The results of the simulations are supported by surface selective nonlinear vibrational spectroscopy, which reveals among other things that the hydronium cations are present at the air/solution interface. The ion specific propensities for the air/solution interface have important implications for a whole range of heterogeneous physical and chemical processes, including atmospheric chemistry of aerosols, corrosion processes, and bubble coalescence. 相似文献
96.
Elizabeth Mudge Lori Paley Andreas Schieber Paula N. Brown 《Analytical and bioanalytical chemistry》2015,407(25):7657-7666
97.
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99.
We prove the convergence of some multiplicative and additive Schwarz methods for inequalities which contain contraction operators. The problem is stated in a reflexive Banach space and it generalizes the well-known fixed-point problem in the Hilbert spaces. Error estimation theorems are given for three multiplicative algorithms and two additive algorithms. We show that these algorithms are in fact Schwarz methods if the subspaces are associated with a decomposition of the domain. Also, for the one- and two-level methods in the finite element spaces, we write the convergence rates as functions of the overlapping and mesh parameters. They are similar with the convergence rates of these methods for linear problems. Besides the direct use of the five algorithms for the inequalities with contraction operators, we can use the above results to obtain the convergence rate of the Schwarz method for other types of inequalities or nonlinear equations. In this way, we prove the convergence and estimate the error of the one- and two-level Schwarz methods for some inequalities in Hilbert spaces which are not of the variational type, and also, for the Navier–Stokes problem. Finally, we give conditions of existence and uniqueness of the solution for all problems we consider. We point out that these conditions and the convergence conditions of the proposed algorithms are of the same type. 相似文献
100.
Lori A. Metz Rosara F. Payne Judah I. Friese Larry R. Greenwood Jeremy D. Kephart Bruce D. Pierson 《Journal of Radioanalytical and Nuclear Chemistry》2009,282(2):373-377
Fission yields are especially well characterized for long-lived fission products. Modeling techniques incorporate numerous
assumptions and can be used to deduce information about the distribution of short-lived fission products. This work is an
attempt to gather experimental (model-independent) data on short-lived fission products. Fissile isotopes of uranium, neptunium,
plutonium and americium were irradiated under pulse conditions at the Washington State University 1 MW TRIGA reactor to achieve
~108 fissions. The samples were placed on an HPGe (high purity germanium) detector to initiate counting in less than 3 min post
irradiation. The data was analyzed to determine which radionuclides could be quantified and compared to the published fission
yield data. 相似文献