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M9480543.TXT
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1994-08-20
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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).