CLONING, EXPRESSION AND PURIFICATION OF A RECOMBINANT POLY-HISTIDINE-LINKED HIV-1 PROTEASE

The gene coding for the HIV-I protease was cloned in an Escherichia co li expression vector adding three-histidine codons to the amino and ca rboxy terminus of the protease sequence. Expression of the protease fr om this construct led to the accumulation of high amounts of insoluble histidine-linked protease entrapped in inclusion bodies. The histidin e-linked protease could be efficiently released from purified inclusio n bodies with 6 M guanidine hydrochloride and further purified by meta l chelate affinity chromatography. The refolded protease cleaved synth etic peptide substrates and the viral polyprotein p55 with the same sp ecificity as the wild type protease. It displays a specific activity o f 4.4 mumol/min/mg.