MUTATIONAL ANALYSIS OF THE FINGERS AND PALM SUBDOMAINS OF HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-1 (HIV-1) REVERSE-TRANSCRIPTASE

We have analyzed the human immunodeficiency virus type-1 reverse trans criptase (HIV-1 RT) polymerase domain between amino acids 91 and 157 b y site-directed mutagenesis. We have constructed a series of amino aci d substitutions using BspMI cassettes, and have assayed the RNA-depend ent DNA polymerase, DNA-dependent DNA polymerase, and RNase H activiti es of the mutant HIV-1 RTs. The regions of HIV-1 RT between amino acid s 91 and 119 and between amino acids 151 and 157 lie within the palm s ubdomain and include part of the polymerase active site. A number of a mino acids within these regions have been identified as being directly or indirectly involved with polymerization, since amino acid substitu tions at these residues decrease the polymerase activity without affec ting RNase H activity. The region of HIV-1 RT between amino acids 120 and 150 lies within the fingers subdomain of the HIV-1 polymerase. We believe that the fingers subdomain plays a role in positioning the tem plate. Many amino acid substitutions in this region decrease or abolis h both the polymerase and the RNase H functions.