Cofactor optimization

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Revision as of 22:20, 18 November 2009 by TheresaRamelot (talk | contribs)
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Often an NMR sample can be improved by adding an appropriate cofactor such as a metal or a small organic molecule. 


Here I have three examples:

  1. Addition of Zn to IscU
  2. Addition of CoA to ?
  3. something else


Addition and removal of Zinc from Haemophilus influenae IscU

As many as 30% of proteins are predicted to be metal binding proteins and many of these may require metal for proper folding. In fact, a recent analysis of the PDB revealed that 14% of non-redundant entries contain stoichiometric amounts of six transition metals: Mn, Fe, Co, Ni, Cu or Zn [1]

Zincfinder by Passerini (2006)

In this example the effect of metal chelation on protein stability was probed by a 2D 1H–15N HSQC NMR experiment. A well dispersed spectra is indicative of global stability, collapsed spectra of instability[2]. Due to the adverse effect of metal chelation on protein stability, and the high prevalence of zinc, it is likely that a subset of NESG targeted proteins with poorly resolved 2D 1H–15N HSQC spectra, may have inadvertently lost structural zinc during the protein sample preparation.

Insert IscU NHSQC figures here

References

  1. Shi, W., Zhan, C., Ignatov, A., Manjasetty, B.A., Marinkovic, N., Sullivan, M., Huang, R., and Chance, M.R. (2005). Metalloproteomics: high-throughput structural and functional annotation of proteins in structural genomics. Structure 13, 1473-1486.
  2. Ramelota, T. et. al. (2004) Solution NMR structure of the iron-sulfur cluster assembly protetin U (IscU) with zinc bound the active site. Journal of Molecular Biology, 344, 567-583