Document 0875
 DOCN  M9540875
 TI    Activities and substrate specificity of the evolutionarily conserved
       central domain of retroviral integrase.
 DT    9504
 AU    Kulkosky J; Katz RA; Merkel G; Skalka AM; Institute for Cancer Research,
       Fox Chase Cancer Center,; Philadelphia, Pennsylvania 19111.
 SO    Virology. 1995 Jan 10;206(1):448-56. Unique Identifier : AIDSLINE
       MED/95133179
 AB    The retroviral integrase (IN) is a virus-encoded enzyme that is
       essential for insertion of viral DNA into the host chromosome. In order
       to map and define the properties of a minimal functional domain for this
       unique viral enzyme, a series of N- and C-terminal deletions of both
       Rous sarcoma virus (RSV) and human immunodeficiency virus (HIV) INs were
       constructed. The RSV IN deletion mutants were first tested for their
       ability to remove two nucleotides from the end of a substrate
       representing the terminus of viral DNA in order to assess the
       contribution of N and C regions towards this reaction, referred to as
       processing. The results suggest that C-terminal amino acids of the
       intact RSV protein are required to maintain specificity of the
       processing reaction. Though deficient for processing, the RSV deletion
       mutants exhibited a secondary endonucleolytic activity that was
       indistinguishable from that of wild-type IN, demonstrating that all
       retained some enzymatic activity. RSV, and a larger set of HIV-1, IN
       deletion mutants were then tested for their ability to perform an
       intramolecular, concerted cleavage-ligation reaction using an
       oligodeoxynucleotide substrate that mimics the intermediate viral-host
       DNA junction found prior to the final step of covalent closure. The
       composite results from such analyses define a minimal functional central
       region of approximately 140 amino acids for each enzyme that includes
       the highly conserved D,D(35)E domain. Results with HIV-1 and HIV-2 IN
       also indicate that the efficiency of concerted cleavage-ligation depends
       upon the presence of CA/GT base pairs within the viral component of the
       DNA substrate at the reaction site. Even the isolated central region of
       HIV-1 IN exhibited this sequence requirement for optimal activity. We
       conclude that this evolutionarily conserved central region of IN not
       only encodes residues that are required for the catalytic activity of
       the enzyme but also harbors some or all of the determinants responsible
       for recognition of the CA/GT dinucleotides that are present at the ends
       of all retroviral DNAs.
 DE    Base Sequence  *Conserved Sequence  DNA
       Nucleotidyltransferases/GENETICS/*METABOLISM  *Evolution  Hydrolysis
       HIV-1/*ENZYMOLOGY  HIV-2/*ENZYMOLOGY  Molecular Sequence Data
       Oligodeoxyribonucleotides  Protein Processing, Post-Translational
       Sarcoma Viruses, Avian/*ENZYMOLOGY  Sequence Deletion  Substrate
       Specificity  Support, Non-U.S. Gov't  Support, U.S. Gov't, P.H.S.
       JOURNAL ARTICLE

       SOURCE: National Library of Medicine.  NOTICE: This material may be
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