Document 0417
 DOCN  M9490417
 TI    Contributions of DNA polymerase subdomains to the RNase H activity of
       human immunodeficiency virus type 1 reverse transcriptase.
 DT    9411
 AU    Smith JS; Gritsman K; Roth MJ; Department of Biochemistry, University of
       Medicine and Dentistry; of New Jersey/Robert Wood Johnson Medical
       School, Piscataway; 08854.
 SO    J Virol. 1994 Sep;68(9):5721-9. Unique Identifier : AIDSLINE
       MED/94335087
 AB    Previous studies showed that an isolated human immunodeficiency virus
       type 1 (HIV-1) RNase H domain expressed as a fusion protein is highly
       active in Mn2+, but activity was dependent on a hexahistidine tag
       located at either the carboxyl or amino terminus of the fusion protein
       (J. Smith and M. Roth, J. Virol. 67:4037-4049, 1993). It was postulated
       that a histidine tag can somehow provide a function normally associated
       with the DNA polymerase domain of HIV-1 reverse transcriptase. To
       determine the contributions of the DNA polymerase subdomains of HIV-1
       reverse transcriptase to its RNase H activity, we have characterized the
       activity of isolated RNase H domains which include either portions of
       the connection, the entire connection, or both the thumb and connection
       as N-terminal extensions. Including increasing lengths of these domains
       at the N terminus of the RNase H resulted in a progressive increase in
       Mn(2+)-dependent RNase H activity that was independent of a histidine
       tag. Activity of the isolated RNase H domains was also stimulated by the
       addition of independently purified polymerase subdomains. Further, this
       stimulation was shown to be a result of direct physical interactions
       between the thumb, connection, and RNase H domains. The connection and
       thumb subdomains were shown to contribute to substrate binding. The
       fingers and palm subdomains were found to be essential for
       Mg(2+)-dependent RNase H activity.
 DE    Base Sequence  DNA Polymerases/CHEMISTRY  DNA Primers/CHEMISTRY
       HIV-1/*ENZYMOLOGY  Molecular Sequence Data  Recombinant Fusion Proteins
       Reverse Transcriptase/*CHEMISTRY  Ribonuclease H, Calf Thymus/*CHEMISTRY
       RNA, Transfer, Lys/METABOLISM  Structure-Activity Relationship
       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
       protected by Copyright Law (Title 17, U.S.Code).