@article{MeyerMainzKehretal.2017,
  author    = {Meyer, Sabine and Mainz, Andi and Kehr, Jan-Christoph and Suessmuth, Roderich and Dittmann, Elke},
  title     = {Prerequisites of Isopeptide Bond Formation in Microcystin Biosynthesis},
  series = {ChemBioChem : a European journal of chemical biology},
  volume    = {18},
  journal   = {ChemBioChem : a European journal of chemical biology},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {1439-4227},
  doi       = {10.1002/cbic.201700389},
  pages     = {2376 -- 2379},
  year      = {2017},
  abstract  = {The biosynthesis of the potent cyanobacterial hepatotoxin microcystin involves isopeptide bond formation through the carboxylic acid side chains of d-glutamate and -methyl d-aspartate. Analysis of the in vitro activation profiles of the two corresponding adenylation domains, McyE-A and McyB-A(2), either in a didomain or a tridomain context with the cognate thiolation domain and the upstream condensation domain revealed that substrate activation of both domains strictly depended on the presence of the condensation domains. We further identified two key amino acids in the binding pockets of both adenylation domains that could serve as a bioinformatic signature of isopeptide bond-forming modules incorporating d-glutamate or d-aspartate. Our findings further contribute to the understanding of the multifaceted role of condensation domains in nonribosomal peptide synthetase assembly lines.},
  language  = {en}
}
@article{LachmannMettlerAltmannWackeretal.2019,
  author    = {Lachmann, Sabrina C. and Mettler-Altmann, Tabea and Wacker, Alexander and Spijkerman, Elly},
  title     = {Nitrate or ammonium},
  series = {Ecology and evolution},
  volume    = {9},
  journal   = {Ecology and evolution},
  number    = {3},
  publisher = {Wiley},
  address   = {Hoboken},
  issn      = {2045-7758},
  doi       = {10.1002/ece3.4790},
  pages     = {13},
  year      = {2019},
  abstract  = {In freshwaters, algal species are exposed to different inorganic nitrogen (Ni) sources whose incorporation varies in biochemical energy demand. We hypothesized that due to the lesser energy requirement of ammonium (NH4+)-use, in contrast to nitrate (NO3-)-use, more energy remains for other metabolic processes, especially under CO2-and phosphorus (Pi) limiting conditions. Therefore, we tested differences in cell characteristics of the green alga Chlamydomonas acidophila grown on NH4+ or NO3- under covariation of CO2 and Pi-supply in order to determine limitations, in a full-factorial design. As expected, results revealed higher carbon fixation rates for NH4+ grown cells compared to growth with NO3- under low CO2 conditions. NO3- -grown cells accumulated more of the nine analyzed amino acids, especially under Pi-limited conditions, compared to cells provided with NH4+. This is probably due to a slower protein synthesis in cells provided with NO3-. In contrast to our expectations, compared to NH4+ -grown cells NO3- -grown cells had higher photosynthetic efficiency under Pi-limitation. In conclusion, growth on the Ni-source NH4+ did not result in a clearly enhanced Ci-assimilation, as it was highly dependent on Pi and CO2 conditions (replete or limited). Results are potentially connected to the fact that C. acidophila is able to use only CO2 as its inorganic carbon (Ci) source.},
  language  = {en}
}