CRYSTALS OF HIV-1 REVERSE-TRANSCRIPTASE DIFFRACTING TO 2-CENTER-DOT-2ANGSTROM RESOLUTION

Reverse transcriptase (RT) from the human immunodeficiency virus type 1 has been crystallized in four closely related forms, the best of whi ch diffract X-rays to 2.2 Angstrom resolution. The RT was crystallized as a complex with a non-nucleoside inhibitor, either nevirapine or a nevirapine analogue. Crystals grew from 6% PEG 3400 buffered at pH 5. These were of space group P2(1)2(1)2(1) with unit cell parameters a = 147 Angstrom, b = 112 Angstrom, c = 79 Angstrom (form A), with one RT heterodimer in the asymmetric unit. Changes in unit cell parameters an d degree of crystalline order were observed on soaking pregrown crysta ls in various solutions, giving three further sets of unit cells. Thes e were a = 143 Angstrom, b = 112 Angstrom, c = 79 Angstrom (form B), a = 141 Angstrom, b = 111 Angstrom, c = 73 Angstrom (form C), a = 143 A ngstrom, b = 117 Angstrom, c = 66.5 Angstrom (form D). The last two fo rms diffract X-rays to 2.2 Angstrom resolution. Structure determinatio ns of these latter crystal forms of RT should give a detailed atomic m odel for this therapeutically important drug target.