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    The potential of fractional diagonal chromatography strategies for the enrichment of post-translational modifications
    (Amsterdam : Elsevier, 2014) Venne, A. Saskia; Zahedi, René P.
    More than 450 post-translational modifications (PTMs) are known, however, currently only some of those can be enriched and analyzed from complex samples such as cell lysates. Therefore, we need additional methods and concepts to improve our understanding about the dynamic crosstalk of PTMs and the highly context-dependent regulation of protein function by so-called ‘PTM codes’. The mere focus on affinity-based enrichment techniques may not be sufficient to achieve this ambitious goal. However, the complementary use of two-dimensional chromatography-based strategies such as COFRADIC and ChaFRADIC might open new avenues for enriching a variety of so far inaccessible PTMs for large-scale proteome studies.
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    Infrared ellipsometric study of hydrogen-bonded long-chain thiolates on gold: Towards resolving structural details
    (Basel : MDPI, 2011) Tsankov, Dimiter; Philipova, Irena; Kostova, Kalina; Hinrichs, Karsten
    A set of newly synthesized aryl-substituted amides of 16-mercaptohexadecanoic acid (R = 4-OH; 3,5-di-OH) are self-assembled on Au(111) substrate. Self assembled monolayers (SAMs) formed by these molecules are studied by ellipsometry from infrared to visible spectral range. Best fit calculations based on the three-phase optical model are employed in order to determine the average tilt angle of the hydrocarbon chains. The data revealed that the SAMs reside in a crystalline-like environment as the long methylene chains predominantly exist in all-trans conformation. The calculated tilt angle of the hydrocarbon chain is decreased by approximately 12° in comparison with the one for the correspondent long-chain n-alkyl thiols. Strong hydrogen bonded networks were detected between the amide proton and the carbonyl oxygen as well as between hydroxyl groups in the end aryl substituents. The transition dipole moments of the C=O, N-H and O-H modes are oriented almost parallel to the gold surface.