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Polymer Adsorption: Fundamentals
Published in E. Desmond Goddard, James V. Gruber, Principles of Polymer Science and Technology in Cosmetics and Personal Care, 1999
E. Desmond Goddard, James V. Gruber
Neutrons can also be totally externally reflected when incident at glancing angles. This forms the basis of the technique known as neutron reflectometry (or reflectivity). For a single interface between media i and j the ratio of the reflected and incident amplitudes defines the Fresnel coefficient:
Platform development for expression and purification of stable isotope labeled monoclonal antibodies in Escherichia coli
Published in mAbs, 2018
Prasad T. Reddy, Robert G. Brinson, J. Todd Hoopes, Colleen McClung, Na Ke, Lila Kashi, Mehmet Berkmen, Zvi Kelman
Monoclonal antibodies (mAbs) represent an important platform for development of biotherapeutic products.1,2 These proteins are typically expressed in mammalian cell lines to enable glycosylation, which plays an important role in mAb function and stability.3 In-depth characterization of mAb structure and dynamics using techniques such as nuclear magnetic resonance spectroscopy (NMR), small angle neutron scattering (SANS) neutron reflectometry (NR) and quantitative mass spectroscopy is highly desirable. However, enrichment of proteins with stable isotopes is a prerequisite for in-depth application of these structural and biophysical methods. To date, expression in mammalian cell lines, which is typical for mAbs, has not proven to be a practical and cost effective path to obtaining such stable isotope labeled samples. Escherichia coli is the most common platform for production of stable isotopically labeled proteins (e.g., 2H, 13C, and 15N)4,5 and nucleic acids6 due to the ability of bacteria to grow in well-defined minimal media, including fully deuterated media. The minimal media contains only salts and an energy source (usually glucose or glycerol) and does not require supplementation with either amino acid or nucleic acids.
Can octapeptin antibiotics combat extensively drug-resistant (XDR) bacteria?
Published in Expert Review of Anti-infective Therapy, 2018
Mark A. T. Blaskovich, Miranda E. Pitt, Alysha G. Elliott, Matthew A. Cooper
A NMR structure determination of OctC4 and a decanoic acid acyl chain analog in the presence of a membrane mimetic, deuterated n-dodecylphosphocholine micelles, showed many more NOE cross-peaks than the solution structure [112]. Both structures were substantially more compact than PmxB, with the N-terminal fatty acid and the D-Phe-Leu segment forming a three-pronged hydrophobic triad which modeling indicates interact with the fatty acyl chains of lipid A. The octapeptin Dab residues interact with the lipid A Kdo2 sugars, rather than the phosphate contacts observed in the modeled polymyxin structure, potentially explaining why the aminoarabinose modifications in polymyxin-resistant strains do not affect octapeptin binding. Together, this data supports the differences in lipid binding seen with the OctA3 neutron reflectometry studies [113]. A solution NMR analysis of the linear OctB5 analog did not indicate any secondary structure [107].