Comparative studies of bacterially expressed integrase proteins of caprine arthritis-encephalitis virus, maedi-visna virus and human immunodeficiency virus type 1.
Integrase (IN) proteins mediate an essential step in retroviral life cycles, the integration of reverse-transcribed viral DNA into the host genome. To create tools for direct comparative investigations, hexahistidine-tagged IN proteins of the phylogenetically related lentiviruses caprine arthritis-encephalitis virus (CAEV), maedi-visna virus (MVV) and human immunodeficiency virus type 1 (HIV-1) were expressed in Escherichia coli. After purification by affinity chromatography, the active enzymes were compared in vitro for their site-specific cleavage, integration and disintegration activities on cognate and non-cognate oligonucleotide substrates. It was found that CAEV IN and MVV IN catalyse both site-specific cleavage and disintegration with high efficiencies, reduced substrate specificities and similar reaction patterns. Comparisons with the respective activities of HIV-1 IN revealed basic functional similarities as well as considerable differences such as more restricted substrate requirements for site-specific cleavage. On the other hand, all three enzymes catalyse disintegration almost independent of the substrate origin. Furthermore, MVV IN was shown to join oligonucleotides as efficiently as HIV-1 IN, albeit with reduced substrate specificity. In contrast, no detectable strand transfer activities occurred with CAEV IN.
Störmann
K D
KD
Federal Research Centre for Virus Diseases of Animals, Tübingen, Federal Republic of Germany.
Schlecht
M C
MC
Pfaff
E
E
D000595:Amino Acid Sequence; D016088:Arthritis-Encephalitis Virus, Caprine / Q000201:enzymology* / Q000235:genetics; D003001:Cloning, Molecular; D004720:Endonucleases / Q000235:genetics; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics*; D005822:Genetic Vectors / Q000096:biosynthesis*; D015497:HIV-1 / Q000201:enzymology* / Q000235:genetics; D019426:Integrases / Q000096:biosynthesis / Q000235:genetics* / Q000302:isolation & purification; D008969:Molecular Sequence Data; D015183:Restriction Mapping; D013379:Substrate Specificity; D016662:Virus Integration; D014790:Visna-maedi virus / Q000201:enzymology* / Q000235:genetics
D019426:Integrases; D004720:Endonucleases