Research Report 2010 2011 - Helmholtz-Zentrum für ...

58 SPECIAL FEATURES | Nuclear Magnetic Resonance Spectroscopy, a Major Player in the Arsenal of Platform Technologies
Large proteins and the compatibility with X-ray
The question now arises as to whether NMR spectroscopy
can also provide structural details for larger proteins and
are the structures determined in solution compatible with
those in the solid phase from X-ray crystallography. In
general, the answer to both questions is yes. Laboratories
such as the HZI Protein Sample Production Facility can now
produce 15 N, 13 C-doubly-labelled protein using recombinant
methods suitable for multi-dimensional heteronuclear NMR
investigations in solution. A salient example is the elucidation
of tryparedoxin, a virulence determinant in trypanosomatids,
the causative agent of trypanosmiasis (sleeping
sickness and Chagas disease) and leishmaniasis. The global
folding of the structure determined by three-dimensional
NMR spectroscopy was very similar to that of the crystal
structure although regions near the active site were less
well defined in solution (figure 8, A and B). Clearly, if the
structure was the only aim of the work, X-ray crystallography
would have been the method of choice. However, NMR
allowed the binding of inhibitory substrate analogues to be
readily investigated and disclosed regions on the protein
surface that are functionally relevant (figure 8, C and D),
which set a framework for the design of more rigid and
active ligands.
Fig. 8. Comparison of NMR and X-ray structures of tryparedoxin (A & B), surface model showing ligand-binding positions (C & D)