Document 0543
 DOCN  M9480543
 TI    Mutagenesis of the conserved aspartic acid 443, glutamic acid 478,
       asparagine 494, and aspartic acid 498 residues in the ribonuclease H
       domain of p66/p51 human immunodeficiency virus type I reverse
       transcriptase. Expression and biochemical analysis.
 DT    9410
 AU    Mizrahi V; Brooksbank RL; Nkabinde NC; Molecular Biology Unit, South
       African Institute for Medical; Research, Johannesburg.
 SO    J Biol Chem. 1994 Jul 29;269(30):19245-9. Unique Identifier : AIDSLINE
       MED/94308199
 AB    The effects of point mutations of the conserved Asp443, Glu478, Asn494,
       and Asp498 residues in the RNase H domain of human immunodeficiency
       virus type I (HIV-1) reverse transcriptase (RT) have been analyzed. The
       mutants fell into two classes: (i) functional RT, but not detectable
       ribonuclease H activity, and (ii) uncharacterizable phenotype due to
       protein instability in the context of the RT/protease Escherichia coli
       co-expression system (Mizrahi, V., Lazarus, G. M., Miles, L. M., Meyers,
       C. A., and Debouck, C. (1989) Arch. Biochem. Biophys. 273, 347-358). The
       only mutation in the former class was D443A, whereas those in the latter
       included D443E, E478D, E478Q, D498E, D443A/D498N, D443E/D498N,
       D443Q/D498N, N494A, N494D, and N494Q. The results were interpreted in
       terms of the x-ray crystal structure of the HIV-1 RNase H domain
       (Davies, J. F., II, Hostomaska, Z., Hostomsky, Z., Jordan, S. R., and
       Matthews, D. A. (1991) Science 252, 88-95) and a general acid-general
       base hydrolysis mechanism (Katayanagi, K., Okumura, M., and Morikawa, K.
       (1993) Proteins Struct. Funct. Genet. 17, 337-346). The data suggested
       that structural perturbations within the RNase H domain interfered with
       maturation of the pol precursor by HIV-1 protease. Analysis of selected
       D443/D498 double mutants suggested that the destabilization caused by
       the D498N mutation could be suppressed by the formation of a new
       hydrogen bond between Asn498 and Asn443.
 DE    Amino Acid Sequence  Asparagine/GENETICS  Aspartic Acid/GENETICS  Base
       Sequence  Comparative Study  Conserved Sequence  DNA Mutational Analysis
       Enzyme Stability/GENETICS  Escherichia coli/GENETICS
       Glutamates/GENETICS  HIV-1/*ENZYMOLOGY  Models, Molecular  Molecular
       Sequence Data  Mutagenesis, Site-Directed  Protein Conformation  Protein
       Denaturation  Reverse Transcriptase/GENETICS/*METABOLISM  Ribonuclease
       H, Calf Thymus/GENETICS/*METABOLISM  Structure-Activity Relationship
       Support, Non-U.S. Gov't  JOURNAL ARTICLE

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