Document 0635
 DOCN  M9460635
 TI    Sensitivity of HIV-1 reverse transcriptase and its mutants to inhibition
       by azidothymidine triphosphate.
 DT    9404
 AU    Carroll SS; Geib J; Olsen DB; Stahlhut M; Shafer JA; Kuo LC; Department
       of Biological Chemistry, Merck Research Labs, West; Point, Pennsylvania
       19486.
 SO    Biochemistry. 1994 Mar 1;33(8):2113-20. Unique Identifier : AIDSLINE
       MED/94162216
 AB    HIV-1 reverse transcriptase can catalyze the addition of either
       azidothymidine monophosphate (AZTMP) or thymidine monophosphate (dTMP)
       to a primer strand opposite template adenosine bases. The ratio of
       incorporation of AZTMP to dTMP as catalyzed by HIV-1 reverse
       transcriptase has been determined to be 0.4 using an RNA-DNA duplex
       substrate prepared from oligonucleotides with sequences taken from the
       HIV-1 genome sequence. Slight variations are found for the incorporation
       ratio of the two nucleotides on other substrates. Substrates containing
       more than one adenosine in the single-stranded part of the template
       allow for more chances to incorporate AZTMP and less full-length
       product. Variations in the intensity of bands on an autoradiograph of a
       DNA sequencing gel corresponding to different positions of incorporation
       of AZTMP suggest that not all template adenosine positions offer the
       same level of discrimination against incorporation of AZTMP. A reverse
       transcriptase containing a set of four mutations (D67N, K70R, T215Y,
       K219Q) known to cause resistance to AZT in cell culture assays has a
       ratio of incorporation that is 0.77 +/- 0.03 times the ratio for the
       wild-type reverse transcriptase opposite one specific template
       adenosine. In contrast, a hybrid mutant containing the same four
       mutations that cause resistance to AZT and an additional mutation,
       Y181C, which by itself causes resistance to the non-nucleoside inhibitor
       L-697,661 [Sardana et al. (1992), J. Biol. Chem. 267, 17526-17530], has
       a ratio of incorporation that is 1.34 +/- 0.01 times that of the
       wild-type, indicating that the hybrid mutant enzyme is more susceptible
       to inhibition by AZTTP than the wild-type reverse
       transcriptase.(ABSTRACT TRUNCATED AT 250 WORDS)
 DE    Antiviral Agents/*PHARMACOLOGY  Base Sequence  Diphosphates/METABOLISM
       DNA Primers  Hydrolysis  HIV-1/*ENZYMOLOGY  Molecular Sequence Data
       Mutagenesis, Site-Directed  *Mutation  Reverse
       Transcriptase/*ANTAGONISTS & INHIB/GENETICS/METABOLISM  Substrate
       Specificity  Templates  Thymidine Monophosphate/METABOLISM  Thymine
       Nucleotides/METABOLISM/*PHARMACOLOGY  Zidovudine/*ANALOGS &
       DERIVATIVES/METABOLISM/PHARMACOLOGY  JOURNAL ARTICLE

       SOURCE: National Library of Medicine.  NOTICE: This material may be
       protected by Copyright Law (Title 17, U.S.Code).