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@MISC{Schrader:873031,
      author       = {Schrader, Tobias Erich},
      title        = {{N}eutron {P}rotein {C}rystallography},
      reportid     = {FZJ-2020-00482},
      year         = {2019},
      abstract     = {With the advent of new instruments (e. g. Imagine at HFIR,
                      MANDI at SNS and BIODIFF at FRMII) neutron protein
                      crystallography has seen a resurrection from the past
                      pioneering work by Goldstein. New sample environment options
                      at the instruments and a growing user community have greatly
                      enhanced the outcome of the existing neutron diffractometers
                      optimized for large unit cells. Measurements at 100 K in a
                      nitrogen gas stream (cryostream) are now routinely possible
                      at neutron diffractometers. Efforts to increase the flux at
                      the sample position and to reduce the background at the
                      detector enables one to measure smaller and smaller protein
                      crystals down to 0.1 mm3 in volume. The neutron single
                      crystal diffractometer BIODIFF at the research reactor Heinz
                      Maier-Leibnitz (FRM II) is especially designed to collect
                      data from crystals with large unit cells. The main field of
                      its application is the structural analysis of proteins,
                      especially the determination of hydrogen atom positions.
                      BIODIFF is a joint project of the Jülich Centre for Neutron
                      Science (JCNS) and the FRM II. BIODIFF is designed as a
                      monochromatic instrument with a narrow wavelength spread of
                      less than 3 $\%.$ To cover a large solid angle the main
                      detector of BIODIFF consists of a neutron imaging plate in a
                      cylindrical geometry with online read-out capability. With a
                      radius of 200 mm and a height of 450 mm it covers a solid
                      angle of approximately 2π with a spatial resolution of up
                      to 125 µm. An optical CCD-camera pointing at the sample
                      position is used to quickly align the sample with respect to
                      the neutron beam. The main advantage of BIODIFF is the
                      possibility to adapt the wavelength to the size of the unit
                      cell of the sample crystal while operating with a clean
                      monochromatic beam that keeps the background level low.
                      BIODFF is equipped with a standard Oxford Cryosystem
                      “Cryostream 700+” which allows measurements in the
                      temperature range from 90 K up to 500 K. A new kappa
                      goniometer head was added recently. This allows an automated
                      tilting of the crystal in order to increase the completeness
                      of the data set when recording another set of frames in the
                      tilted geometry without the need to take the crystal off
                      from the goniometer head. Typical scientific questions
                      addressed are the determination of protonation states of
                      amino acid side chains in proteins and the characterization
                      of the hydrogen bonding networks between the protein active
                      centre and an inhibitor or substrate. One application
                      example is the improvement of antibiotic drugs. Many
                      bacteria secret a protein called -lactamase into their
                      environment. This protein is able to hydrolyse the four
                      membered carbon atom ring in beta-lactam antibiotics. These
                      antibiotics are thereby destroyed and are not harmful to the
                      bacteria any more. This mechanism causes great problems in
                      hospitals. With neutron protein crystallography we were able
                      to find a deuterium atom at the amino acid side chain
                      glutamate 166 in the beta-lactamase protein carrying a
                      transition state analogue. This transition state analogue
                      stops the enzymatic reaction in its first acylation step.
                      Thereby one could identify glutamate 166 as the important
                      base taking over the hydrogen atom in the acylation step.
                      Improved antibiotics should find ways to bind to this side
                      chain in order to prevent its action as a base. Or, an
                      additional drug has to be given which blocks the
                      beta-lactamase protein efficiently such the antibiotics can
                      work effectively.},
      month         = {Feb},
      date          = {2019-02-27},
      organization  = {(Russia), 27 Feb 2019 - 27 Feb 2019},
      subtyp        = {Invited},
      cin          = {JCNS-FRM-II / JCNS-1 / MLZ},
      cid          = {I:(DE-Juel1)JCNS-FRM-II-20110218 /
                      I:(DE-Juel1)JCNS-1-20110106 / I:(DE-588b)4597118-3},
      pnm          = {6G4 - Jülich Centre for Neutron Research (JCNS) (POF3-623)
                      / 6G15 - FRM II / MLZ (POF3-6G15) / 6215 - Soft Matter,
                      Health and Life Sciences (POF3-621)},
      pid          = {G:(DE-HGF)POF3-6G4 / G:(DE-HGF)POF3-6G15 /
                      G:(DE-HGF)POF3-6215},
      experiment   = {EXP:(DE-MLZ)BIODIFF-20140101},
      typ          = {PUB:(DE-HGF)17},
      url          = {https://juser.fz-juelich.de/record/873031},
}