TY - JOUR A1 - Wolff, Martin A1 - Schüler, Anja A1 - Gast, Klaus A1 - Seckler, Robert A1 - Evers, Andreas A1 - Pfeiffer-Marek, Stefania A1 - Kurz, Michael A1 - Nagel, Norbert A1 - Haack, Torsten A1 - Wagner, Michael A1 - Thalhammer, Anja T1 - Self-Assembly of Exendin-4-Derived Dual Peptide Agonists is Mediated by Acylation and Correlated to the Length of Conjugated Fatty Acyl Chains JF - Molecular pharmaceutics N2 - Dual glucagon-like peptide-1/glucagon receptor agonists have emerged as promising candidates for the treatment of diabetes and obesity. Issues of degradation sensitivity and rapid renal clearance are addressed, for example, by the conjugation of peptides to fatty acid chains, promoting reversible albumin binding. We use combined dynamic and static light scattering to directly measure the self-assembly of a set of dual peptide agonists based on the exendin-4 structure with varying fatty acid chain lengths in terms of apparent molecular mass and hydrodynamic radius (R-S). We use NMR spectroscopy to gain an insight into the molecular architecture of the assembly. We investigate conformational changes of the monomeric subunits resulting from peptide self-assembly and assembly stability as a function of the fatty acid chain length using circular dichroism and fluorescence spectroscopy. Our results demonstrate that self-assembly of the exendin-4-derived dual agonist peptides is essentially driven by hydrophobic interactions involving the conjugated acyl chains. The fatty acid chain length affects assembly equilibria and the assembly stability, although the peptide subunits in the assembly retain a dynamic secondary structure. The assembly architecture is characterized by juxtaposition of the fatty acyl side chains and a hydrophobic cluster of the peptide moiety. This cluster experiences local conformational changes in the assembly compared to the monomeric unit leading to a reduction in solvent exposure. The N-terminal half of the peptide and a C-terminal loop are not in contact with neighboring peptide subunits in the assemblies. Altogether, our study contributes to a thorough understanding of the association characteristics and the tendency toward self-assembly in response to lipidation. This is important not only to achieve the desired bioavailability but also with respect to the physical stability of peptide solutions. KW - dual GLP-1/glucagon receptor agonist KW - self-assembly KW - light scattering KW - molecular architecture KW - lipidation KW - exendin-4 Y1 - 2020 U6 - https://doi.org/10.1021/acs.molpharmaceut.9b01195 SN - 1543-8384 VL - 17 IS - 3 SP - 965 EP - 978 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Wolff, Martin A1 - Schüler, Anja A1 - Gast, Klaus A1 - Seckler, Robert A1 - Evers, Andreas A1 - Pfeiffer-Marek, Stefania A1 - Kurz, Michael A1 - Nagel, Norbert A1 - Haack, Torsten A1 - Wagner, Michael A1 - Thalhammer, Anja T1 - Self-Assembly of Exendin-4-Derived Dual Peptide Agonists is Mediated by Acylation and Correlated to the Length of Conjugated Fatty Acyl Chains JF - Molecular pharmaceutics N2 - Dual glucagon-like peptide-1/glucagon receptor agonists have emerged as promising candidates for the treatment of diabetes and obesity. Issues of degradation sensitivity and rapid renal clearance are addressed, for example, by the conjugation of peptides to fatty acid chains, promoting reversible albumin binding. We use combined dynamic and static light scattering to directly measure the self-assembly of a set of dual peptide agonists based on the exendin-4 structure with varying fatty acid chain lengths in terms of apparent molecular mass and hydrodynamic radius (R-S). We use NMR spectroscopy to gain an insight into the molecular architecture of the assembly. We investigate conformational changes of the monomeric subunits resulting from peptide self-assembly and assembly stability as a function of the fatty acid chain length using circular dichroism and fluorescence spectroscopy. Our results demonstrate that self-assembly of the exendin-4-derived dual agonist peptides is essentially driven by hydrophobic interactions involving the conjugated acyl chains. The fatty acid chain length affects assembly equilibria and the assembly stability, although the peptide subunits in the assembly retain a dynamic secondary structure. The assembly architecture is characterized by juxtaposition of the fatty acyl side chains and a hydrophobic cluster of the peptide moiety. This cluster experiences local conformational changes in the assembly compared to the monomeric unit leading to a reduction in solvent exposure. The N-terminal half of the peptide and a C-terminal loop are not in contact with neighboring peptide subunits in the assemblies. Altogether, our study contributes to a thorough understanding of the association characteristics and the tendency toward self-assembly in response to lipidation. This is important not only to achieve the desired bioavailability but also with respect to the physical stability of peptide solutions. KW - dual GLP-1/glucagon receptor agonist KW - self-assembly KW - light scattering KW - molecular architecture KW - lipidation KW - exendin-4 Y1 - 2020 U6 - https://doi.org/10.1021/acs.molpharmaceut.9b01195 SN - 1543-8384 SN - 1543-8392 VL - 17 IS - 3 SP - 965 EP - 978 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Liu, Qi A1 - Adler, Karsten A1 - Lipus, Daniel A1 - Kämpf, Horst A1 - Bussert, Robert A1 - Plessen, Birgit A1 - Schulz, Hans-Martin A1 - Krauze, Patryk A1 - Horn, Fabian A1 - Wagner, Dirk A1 - Mangelsdorf, Kai A1 - Alawi, Mashal T1 - Microbial signatures in deep CO2-saturated miocene sediments of the active Hartousov mofette system (NW Czech Republic) JF - Frontiers in microbiology N2 - The Hartousov mofette system is a natural CO2 degassing site in the central Cheb Basin (Eger Rift, Central Europe). In early 2016 a 108 m deep core was obtained from this system to investigate the impact of ascending mantle-derived CO2 on indigenous deep microbial communities and their surrounding life habitat. During drilling, a CO2 blow out occurred at a depth of 78.5 meter below surface (mbs) suggesting a CO2 reservoir associated with a deep low-permeable CO2-saturated saline aquifer at the transition from Early Miocene terrestrial to lacustrine sediments. Past microbial communities were investigated by hopanoids and glycerol dialkyl glycerol tetraethers (GDGTs) reflecting the environmental conditions during the time of deposition rather than showing a signal of the current deep biosphere. The composition and distribution of the deep microbial community potentially stimulated by the upward migration of CO2 starting during Mid Pleistocene time was investigated by intact polar lipids (IPLs), quantitative polymerase chain reaction (qPCR), and deoxyribonucleic acid (DNA) analysis. The deep biosphere is characterized by microorganisms that are linked to the distribution and migration of the ascending CO2-saturated groundwater and the availability of organic matter instead of being linked to single lithological units of the investigated rock profile. Our findings revealed high relative abundances of common soil and water bacteria, in particular the facultative, anaerobic and potential iron-oxidizing Acidovorax and other members of the family Comamonadaceae across the whole recovered core. The results also highlighted the frequent detection of the putative sulfate-oxidizing and CO2-fixating genus Sulfuricurvum at certain depths. A set of new IPLs are suggested to be indicative for microorganisms associated to CO2 accumulation in the mofette system. KW - geo-bio interaction KW - CO2 KW - mofette systems KW - Eger Rift KW - microbial lipid KW - biomarker KW - microbial diversity KW - deep biosphere KW - saline groundwater Y1 - 2020 U6 - https://doi.org/10.3389/fmicb.2020.543260 SN - 1664-302X VL - 11 PB - Frontiers Media CY - Lausanne ER -