The search for suitable heavy-atom derivatives can be quite tedious and binding of heavy atoms often results in disrupting the crystal lattice. Halogenated ATP and GTP analogs however, provide an alternative method that allows rational incorporation of heavy atoms into a large number of physiologically relevant enzymes:
The JBS Halo-ATP Kit contains 8 halogenated Adenosine nucleotides (5 nmol as lyophilized sodium salts):
The JBS Halo-GTP Kit contains 4 halogenated Guanosine nucleotides (5 nmol as lyophilized sodium salts):
The protein under investigation can either be co-crystallized with the respective analog, or the nucleotide can be added directly to the crystallization drops containing pre-grown crystals. Since it is difficult to predict a priori which one of the Halo-nucleotides will give the highest quality derivative crystals, it is advisable to screen them all in parallel.
Co-crystals of human TMP-kinase and 2'Br-ADP/ATP
Also check out our section of Halogenated, Mercurated and Selenium-containing Nucleotides!
Gruen et al. (1999) 2'-Halo-ATP and -GTP analogues: Rational phasing tools for protein crystallography. Protein Sci. 8:2524.
Gruen et al. (1999) Synthesis of 2'-iodo- and 2'-bromo-ATP and GTP analogues as potential phasing tools for X-ray crystallography. Nucleos. Nucleot. 18 (1):137.
Naber et al. (1995) A novel adenosine-triphosphate analog with a heavy-atom to target the nucleotide-binding site of proteins. Protein Sci. 4:1824.