title: Structural requirements for enzymatic activities of foamy virus protease-reverse transcriptase.
abstract: Reverse transcriptases (RTs) are pivotal in the life cycle of retroviruses and convert the genomic viral RNA into double-stranded DNA. The RT polymerase domain is subdivided into fingers, palm, thumb, and the connection subdomain, which links the polymerase to the C-terminal RNase H domain. In contrast to orthoretroviruses, mature RT of foamy viruses harbors the protease (PR) domain at its N-terminus (PR-RT). Therefore and due to low homology to other RTs, it is difficult to define the boundaries and functions of the (sub)domains. We introduced N- and C-terminal deletions into simian foamy virus PR-RT to investigate the impact of the truncations on the catalytic activities. Both, the RNase H domain and the connection subdomain contribute substantially to polymerase integrity and stability as well as to polymerase activity and substrate binding. The 42 amino acids long region C-terminal of the PR is important for polymerase stability and activity. PR activation via binding of PR-RT to viral RNA requires the presence of the full length PR-RT including the RNase H domain. In vitro, the cleavage efficiencies of FV PR for the Gag and Pol cleavage site are comparable, even though in virus particles only the Pol site is cleaved to completion suggesting that additional factors control PR activity and that virus maturation needs to be strictly regulated.
authors: Universität Bayreuth, Lehrstuhl Biopolymere, Universitätsstr. 30, D-95447, Bayreuth, Germany.
authors: Anna
authors: A
authors: Schneider
authors: Daniel
authors: D
authors: Peter
authors: Jessica
authors: J
authors: Schmitt
authors: Berit
authors: B
authors: Leo
authors: Franziska
authors: F
authors: Richter
authors: Paul
authors: P
authors: Rösch
authors: Birgitta M
authors: BM
authors: Wöhrl
authors: Maximilian J
authors: MJ
authors: Hartl
mesh_terms: D009154:Mutation; D010447:Peptide Hydrolases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D058105:Polymerization; D017434:Protein Structure, Tertiary; D012194:RNA-Directed DNA Polymerase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D016914:Ribonuclease H / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D016092:Spumavirus / Q000201:enzymology* / Q000235:genetics; D014764:Viral Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
chemical_list: D014764:Viral Proteins; D012194:RNA-Directed DNA Polymerase; D016914:Ribonuclease H; D010447:Peptide Hydrolases
keywords: domain structure; enzyme activity; foamy virus; retroviral protease; reverse transcriptase; substrate binding