Important note: Information in this article was accurate in 1996. The state of the art may have changed since the publication date.
Effect of human immunodeficiency virus type 1 (HIV-1) nucleocapsid protein on HIV-1 reverse transcriptase activity in vitro.
Biochemistry. 1996 Jan 9;35(1):132-43. Unique Identifier : AIDSLINE MED/96134828 Ji X; Klarmann GJ; Preston BD; Department of Biochemistry, University of Utah, Salt Lake City; 84112, USA.
Abstract:
Conversion of human immunodeficiency virus type 1 (HIV-1) genomic RNA to viral DNA is a requisite step in the virus life cycle. This conversion is catalyzed by reverse transcriptase (RT) associated with a large nucleoprotein complex composed of several viral proteins including nucleocapsid (NC). To better characterize the biochemical mechanisms of viral DNA synthesis, we overexpressed and purified recombinant HIV-1 NC and studied its effect on the activity and processivity of HIV-1 RT during polymerization of HIV-1 template sequences in vitro. The effect of NC on steady-state RT activity was dependent on the order of addition of reaction components. Addition of NC prior to formation of RT-primer.template-dNTP ternary complexes inhibited primer extension and reduced total product yields by slowing steady-state RT turnover. In contrast, addition of NC to preformed ternary complexes resulted in efficient primer extension and increased RT processivity at specific DNA template sites. NC stimulated polymerization (2-4 times) through eight of 13 sites examined in the cRRE region of HIV-1 env and increased the rate of polymerization through the D3/CTS region of HIV-1 pol 10 times. The data suggest that NC affects RT processivity by facilitating polymerization through regions of template secondary structure. Thus, NC functions as a single-strand binding (SSB)-like accessory replication factor for RT in vitro and may be part of a multicomponent retroviral replication complex.
Keywords: Base Sequence Binding Sites Capsid/*PHARMACOLOGY DNA Primers Electrophoresis, Polyacrylamide Gel Human HIV-1/*METABOLISM Macromolecular Systems Molecular Sequence Data Molecular Weight Polymerase Chain Reaction Recombinant Proteins/CHEMISTRY/ISOLATION & PURIF/METABOLISM RNA-Directed DNA Polymerase/CHEMISTRY/ISOLATION & PURIF/ *METABOLISM Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S. Templates Viral Core Proteins/*PHARMACOLOGY JOURNAL ARTICLE 960530
M9651071
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Important note: Information in this article was accurate in 1996. The state of the art may have changed since the publication date.
