@unpublished{NeitzBessiKuperetal.2023,
  author    = {Neitz, Hermann and Bessi, Irene and Kuper, Jochen and Kisker, Caroline and H{\"o}bartner, Claudia},
  title     = {Programmable DNA interstrand crosslinking by alkene-alkyne [2+2] photocycloaddition},
  series = {Journal of the American Chemical Society},
  journal   = {Journal of the American Chemical Society},
  edition   = {submitted version},
  doi       = {10.1021/jacs.3c01611},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-311822},
  year      = {2023},
  abstract  = {Covalent crosslinking of DNA strands provides a useful tool for medical, biochemical and DNA nanotechnology applications. Here we present a light-induced interstrand DNA crosslinking reaction using the modified nucleoside 5-phenylethynyl-2'-deoxyuridine (\(^{Phe}\)dU). The crosslinking ability of \(^{Phe}\)dU was programmed by base pairing and by metal ion interaction at the Watson-Crick base pairing site. Rotation to intrahelical positions was favored by hydrophobic stacking and enabled an unexpected photochemical alkene-alkyne [2+2] cycloaddition within the DNA duplex, resulting in efficient formation of a \(^{Phe}\)dU-dimer after short irradiation times of a few seconds. A \(^{Phe}\)dU dimer-containing DNA was shown to efficiently bind a helicase complex, but the covalent crosslink completely prevented DNA unwinding, suggesting possible applications in biochemistry or structural biology.},
  language  = {en}
}
@unpublished{ScheitlMieczkowskiSchindelinetal.2022,
  author    = {Scheitl, Carolin P. M. and Mieczkowski, Mateusz and Schindelin, Hermann and H{\"o}bartner, Claudia},
  title     = {Structure and mechanism of the methyltransferase ribozyme MTR1},
  series = {Nature Chemical Biology},
  journal   = {Nature Chemical Biology},
  edition   = {submitted version},
  doi       = {10.1038/s41589-022-00976-x},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-272170},
  year      = {2022},
  abstract  = {RNA-catalysed RNA methylation was recently shown to be part of the catalytic repertoire of ribozymes. The methyltransferase ribozyme MTR1 catalyses the site-specific synthesis of 1-methyladenosine (m\(^1\)A) in RNA, using O\(^6\)-methylguanine (m\(^6\)G) as methyl group donor. Here we report the crystal structure of MTR1 at a resolution of 2.8 {\AA}, which reveals a guanine binding site reminiscent of natural guanine riboswitches. The structure represents the postcatalytic state of a split ribozyme in complex with the m1A-containing RNA product and the demethylated cofactor guanine. The structural data suggest the mechanistic involvement of a protonated cytidine in the methyl transfer reaction. A synergistic effect of two 2'-O-methylated ribose residues in the active site results in accelerated methyl group transfer. Supported by these results, it seems plausible that modified nucleotides may have enhanced early RNA catalysis and that metabolite-binding riboswitches may resemble inactivated ribozymes that have lost their catalytic activity during evolution.},
  language  = {en}
}