@article{MakbulKraftGriessmannetal.2021,
  author    = {Makbul, Cihan and Kraft, Christian and Grießmann, Matthias and Rasmussen, Tim and Katzenberger, Kilian and Lappe, Melina and Pfarr, Paul and Stoffer, Cato and St{\"o}hr, Mara and Wandinger, Anna-Maria and B{\"o}ttcher, Bettina},
  title     = {Binding of a pocket factor to Hepatitis B virus capsids changes the rotamer conformation of Phenylalanine 97},
  series = {Viruses},
  volume    = {13},
  journal   = {Viruses},
  number    = {11},
  issn      = {1999-4915},
  doi       = {10.3390/v13112115},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-248565},
  year      = {2021},
  abstract  = {(1) Background: During maturation of the Hepatitis B virus, a viral polymerase inside the capsid transcribes a pre-genomic RNA into a partly double stranded DNA-genome. This is followed by envelopment with surface proteins inserted into a membrane. Envelopment is hypothetically regulated by a structural signal that reports the maturation state of the genome. NMR data suggest that such a signal can be mimicked by the binding of the detergent Triton X 100 to hydrophobic pockets in the capsid spikes. (2) Methods: We have used electron cryo-microscopy and image processing to elucidate the structural changes that are concomitant with the binding of Triton X 100. (3) Results: Our maps show that Triton X 100 binds with its hydrophobic head group inside the pocket. The hydrophilic tail delineates the outside of the spike and is coordinated via Lys-96. The binding of Triton X 100 changes the rotamer conformation of Phe-97 in helix 4, which enables a π-stacking interaction with Trp-62 in helix 3. Similar changes occur in mutants with low secretion phenotypes (P5T and L60V) and in a mutant with a pre-mature secretion phenotype (F97L). (4) Conclusion: Binding of Triton X 100 is unlikely to mimic structural maturation because mutants with different secretion phenotypes show similar structural responses.},
  language  = {en}
}
@article{MakbulKhayenkoMaricetal.2021,
  author    = {Makbul, Cihan and Khayenko, Vladimir and Maric, Hans Michael and B{\"o}ttcher, Bettina},
  title     = {Conformational Plasticity of Hepatitis B Core Protein Spikes Promotes Peptide Binding Independent of the Secretion Phenotype},
  series = {Microorganisms},
  volume    = {9},
  journal   = {Microorganisms},
  number    = {5},
  issn      = {2076-2607},
  doi       = {10.3390/microorganisms9050956},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-236720},
  year      = {2021},
  abstract  = {Hepatitis B virus is a major human pathogen, which forms enveloped virus particles. During viral maturation, membrane-bound hepatitis B surface proteins package hepatitis B core protein capsids. This process is intercepted by certain peptides with an "LLGRMKG" motif that binds to the capsids at the tips of dimeric spikes. With microcalorimetry, electron cryo microscopy and peptide microarray-based screens, we have characterized the structural and thermodynamic properties of peptide binding to hepatitis B core protein capsids with different secretion phenotypes. The peptide "GSLLGRMKGA" binds weakly to hepatitis B core protein capsids and mutant capsids with a premature (F97L) or low-secretion phenotype (L60V and P5T). With electron cryo microscopy, we provide novel structures for L60V and P5T and demonstrate that binding occurs at the tips of the spikes at the dimer interface, splaying the helices apart independent of the secretion phenotype. Peptide array screening identifies "SLLGRM" as the core binding motif. This shortened motif binds only to one of the two spikes in the asymmetric unit of the capsid and induces a much smaller conformational change. Altogether, these comprehensive studies suggest that the tips of the spikes act as an autonomous binding platform that is unaffected by mutations that affect secretion phenotypes.},
  language  = {en}
}