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Phasing Kits - Tantalum Cluster Derivatization Kit


Heavy atom derivatization of biological macromolecules for isomorphous and/or anomalous phasing methods.

Kit Contents

6 pre-weighted solid aliquots of hexatantalum tetradecabromide at 1 mg.

The Tantalum Bromide Cluster, manufactured by Proteros biostructures GmbH, is utilized for the preparation of heavy-atom derivatives for structure determination of biological macromolecules by X-ray analysis.

This very electron-rich compound induces significant changes in crystal diffraction required for convenient phase calculation in single and multiple isomorphous replacement (SIR and MIR) experiments and in anomalous dispersion (SAD and MAD) experiments.
The two present anomalous scatterers Ta and Br are useful for determining the cluster orientation for low resolution datasets.
Tantalum Bromide Clusters have been successfully employed in several structural studies because of their high electron-density, solubility in aqueous solutions and stability over a wide pH range.


  • Dahms et al. (2013) Localization and orientation of heavy-atom cluster compounds in protein crystals using molecular replacement. Acta Cryst. D69:284.
  • Szczepanowski et al. (2005) Crystal structure of a fragment of mouse ubiquitin-activating enzyme. J. Biol. Chem. 280:22006.
  • Gomis-Rüth et al. (2001) Solving a 300 kDa multimeric protein by low-resolution MAD phasing and averaging/phase extension. Acta Cryst. D 57:800.
  • Yonath et al. (1998) Crystallographic studies on the ribosome, a large macromolecular assembly exhibiting severe nonisomorphism, extreme beam sensitivity and no internal symmetry. Acta Cryst. A 54:945.
  • Knäblein et al. (1997) Ta6Br122+, a tool for phase determination of large biological assemblies by X-ray crystallography. J. Mol. Biol. 270:1.

Selected Literature Citations of Tantalum Cluster Derivatization Kit

  • Li et al. (2015) Experimental phasing for structure determination using membrane-protein crystals grown by the lipid cubic phase method. Acta Cryst D 71:104.
  • Wu et al. (2014) Lsm2 and Lsm3 bridge the interaction of the Lsm1-7 complex with Pat1 for decapping activation. Cell Research 24:233.
  • Siu et al. (2013) Structure of the human glucagon class B G-protein-coupled receptor. Nature 499:444.
  • Wang et al. (2013) Structure of the human smoothened receptor bound to an antitumour agent. Nature 497:338.
  • Cao et al. (2013) Gating of the TrkH Ion Channel by its Associated RCK Protein, Trka. Nature 496:317.
  • Montaño et al. (2012) Structure of the Mu transpososome illuminates evolution of DDE recombinases. Nature 491:413.
  • Zhou et al. (2012) Insights into Diterpene Cyclization from Structure of Bifunctional Abietadiene Synthase from Abies grandis. JBC 287:6840.
  • Spinelli et al. (2012) Crystal structure of Apis mellifera OBP14, a C-minus odorant-binding protein, and its complexes with odorant molecules. Insect Biochemistry and Molecular Biology 42(1):41.
  • De et al. (2011) Crystal structure of the Vibrio cholerae cytolysin heptamer reveals common features among disparate pore-forming toxins. PNAS 108(18):7385.