JBS Halo Kits
The search for suitable heavy-atom derivatives can be quite tedious. Binding of heavy atoms often disrupts the crystal lattice. Halogenated ATP and GTP analogs provide an alternative method that allows rational incorporation of heavy atoms into a large number of physiologically relevant enzymes
- In the human genome alone, estimated 5,000 to 10,000 proteins interact with ATP or GTP, e.g. protein and nucleotide kinases, motor proteins, chaperones or the superfamily of GTPases, respectively.
- The incorporation of iodine or bromine allows MIR or MAD phasing for proteins with molecular weights of at least up to 50 kDa. Importantly, for MIR experiments, such derivatives are likely to be isomorphous to the native crystals
- The binding kinetics of 2′-halogenated ATP analogs to most enzymes so far investigated (including myosin, creatine kinase, hexokinase, pyruvate kinase and UMP/CMP kinase) are similar to those of non-substituted ATP.
- The complexes of 2′-halogenated GTP analogs with the GTPases p21ras or Rab5 have dissociation constants well suitable for crystallization.
- Several proteins including kinesin, non-claret disjunctional protein and TMP kinase have been sucessfully crystallized with 2′-halogenated analogs.
The JBS Halo-ATP Kit contains 12 halogenated Adenosine nucleotides (50 units* as lyophilized Sodium salts):
- 2′-Iodo-ADP, 2′-Iodo-ATP, 2′-Iodo-AppNHp (2′-Iodo-AMPPNP)
- 2′-Bromo-ADP, 2′-Bromo-ATP, 2′-Bromo-AppNHp (2′-Bromo-AMPPNP)
- 8-Iodo-ADP, 8-Iodo-ATP, 8-Iodo-AppNHp (8-Iodo-AMPPNP)
- 8-Bromo-ADP, 8-Bromo-ATP, 8-Bromo-AppNHp (8-Bromo-AMPPNP)
The JBS Halo-GTP Kit contains 6 halogenated Guanosine nucleotides (50 units* as lyophilized sodium salts):
- 8-Iodo-GDP, 8-Iodo-GTP, 8-Iodo-GppNHp (8-Iodo-GMPPNP)
- 8-Bromo-GDP, 8-Bromo-GTP, 8-Bromo-GppNHp (8-Bromo-GMPPNP)
* 1 unit = 1 μl of a 10 mM solution.