THE GROWTH AND CHARACTERIZATION OF CRYSTALS OF HUMAN-IMMUNODEFICIENCY-VIRUS (HIV) REVERSE-TRANSCRIPTASE

Extensive studies on the crystallization of HIV-1 reverse transcriptase (RT) have yielded several crystal forms, two of which show diffraction to minimum Bragg spacings of 6 angstrom or better. Type 1 crystals belong to the space group P2(1)2(1)2(1) with unit cell dimensions a = 147 angstrom, b = 190 angstrom and c = 182 angstrom. Crystal density measurements indicate a very high crystal solvent content of 77% consistent with the presence of two RT heterodimers (66k/51k) per crystallographic asymmetric unit. These crystals are suitable for a low resolution determination of the apoenzyme structure. The second well ordered crystal form (space group P4(2)22 with unit cell dimensions a = b = 120 angstrom, c = 320 angstrom) results from the co-crystallization of RT heterodimer and a double-stranded DNA oligonucleotide. Crystal density measurements again yield a relatively high value for the solvent content (70%; one RT heterodimer per crystallographic asymmetric unit) and elemental analysis indicates that one DNA oligonucleotide is associated with each RT heterodimer. This is consistent with each heterodimer possessing a single, competent, active site.