The K65R mutant reverse transcriptase of HIV-1 cross-resistant to 2', 3'-dideoxycytidine, 2',3'-dideoxy-3'-thiacytidine, and 2',3'-dideoxyinosine shows reduced sensitivity to specific dideoxynucleoside triphosphate inhibitors in vitro. 1994

Z Gu, and R S Fletcher, and E J Arts, and M A Wainberg, and M A Parniak
Lady Davis Institute for Medical Research, Sir Mortimer B. Davis-Jewish General Hospital, Montreal, Quebec, Canada.

The K65R mutation in human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) encodes cross-resistance to 2',3'-dideoxycytidine (ddC), 2',3'-dideoxy-3'-thiacytidine (3TC), and 2',3'-dideoxyinosine (ddI). We characterized the in vitro sensitivities of recombinant wild type (wt) and K65R mutant RT to dideoxynucleoside triphosphate (ddNTP) inhibitors, using a variety of primer-templates. With poly(rA)-oligo(dT), the K65R mutant showed slight increases in Ki for ddTTP and 3'-azido, 3'-deoxythymidine triphosphate (AZTTP) compared to wt RT, but neither wt nor K65R RT was inhibited by ddCTP or ddATP. With poly(rI)-oligo(dC), the K65R mutant showed a 2-fold increase in Km for dCTP and a 20-fold increase in Ki for ddCTP compared to wt, whereas ddATP, ddTTP, and AZTTP failed to inhibit either enzyme. With a heteropolymeric primer-template, the K65R mutant showed 10-fold reduced sensitivities to ddCTP, 3TCTP, and ddATP, and 4-fold reduced sensitivity to AZTTP, compared to wt. In contrast, both enzymes were equally inhibited by ddTTP and ddGTP. HIV-1 cross-resistance to ddC/3TC/ddI resulting from the K65R mutation may therefore involve selective alterations in substrate/inhibitor recognition. Additionally, competitive inhibition by ddNTPs noncomplementary to the template base appears to be unimportant in the mechanism of inhibition of HIV-1 RT by dideoxynucleoside analogs.

UI MeSH Term Description Entries
D007700 Kinetics The rate dynamics in chemical or physical systems.
D008969 Molecular Sequence Data Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories. Sequence Data, Molecular,Molecular Sequencing Data,Data, Molecular Sequence,Data, Molecular Sequencing,Sequencing Data, Molecular
D011119 Polynucleotides BIOPOLYMERS composed of NUCLEOTIDES covalently bonded in a chain. The most common examples are DNA and RNA chains. Polynucleotide
D011994 Recombinant Proteins Proteins prepared by recombinant DNA technology. Biosynthetic Protein,Biosynthetic Proteins,DNA Recombinant Proteins,Recombinant Protein,Proteins, Biosynthetic,Proteins, Recombinant DNA,DNA Proteins, Recombinant,Protein, Biosynthetic,Protein, Recombinant,Proteins, DNA Recombinant,Proteins, Recombinant,Recombinant DNA Proteins,Recombinant Proteins, DNA
D003001 Cloning, Molecular The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells. Molecular Cloning
D004352 Drug Resistance, Microbial The ability of microorganisms, especially bacteria, to resist or to become tolerant to chemotherapeutic agents, antimicrobial agents, or antibiotics. This resistance may be acquired through gene mutation or foreign DNA in transmissible plasmids (R FACTORS). Antibiotic Resistance,Antibiotic Resistance, Microbial,Antimicrobial Resistance, Drug,Antimicrobial Drug Resistance,Antimicrobial Drug Resistances,Antimicrobial Resistances, Drug,Drug Antimicrobial Resistance,Drug Antimicrobial Resistances,Drug Resistances, Microbial,Resistance, Antibiotic,Resistance, Drug Antimicrobial,Resistances, Drug Antimicrobial
D000595 Amino Acid Sequence The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION. Protein Structure, Primary,Amino Acid Sequences,Sequence, Amino Acid,Sequences, Amino Acid,Primary Protein Structure,Primary Protein Structures,Protein Structures, Primary,Structure, Primary Protein,Structures, Primary Protein
D000998 Antiviral Agents Agents used in the prophylaxis or therapy of VIRUS DISEASES. Some of the ways they may act include preventing viral replication by inhibiting viral DNA polymerase; binding to specific cell-surface receptors and inhibiting viral penetration or uncoating; inhibiting viral protein synthesis; or blocking late stages of virus assembly. Antiviral,Antiviral Agent,Antiviral Drug,Antivirals,Antiviral Drugs,Agent, Antiviral,Agents, Antiviral,Drug, Antiviral,Drugs, Antiviral
D001483 Base Sequence The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence. DNA Sequence,Nucleotide Sequence,RNA Sequence,DNA Sequences,Base Sequences,Nucleotide Sequences,RNA Sequences,Sequence, Base,Sequence, DNA,Sequence, Nucleotide,Sequence, RNA,Sequences, Base,Sequences, DNA,Sequences, Nucleotide,Sequences, RNA
D012194 RNA-Directed DNA Polymerase An enzyme that synthesizes DNA on an RNA template. It is encoded by the pol gene of retroviruses and by certain retrovirus-like elements. EC 2.7.7.49. DNA Polymerase, RNA-Directed,RNA-Dependent DNA Polymerase,Reverse Transcriptase,RNA Transcriptase,Revertase,DNA Polymerase, RNA Directed,DNA Polymerase, RNA-Dependent,RNA Dependent DNA Polymerase,RNA Directed DNA Polymerase

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