Bovine papillomavirus type 1 E1 ATPase activity does not depend on binding to DNA nor to viral E2 protein.
J Gen Virol
; 76 ( Pt 5): 1129-40, 1995 May.
Article
em En
| MEDLINE
| ID: mdl-7730798
ABSTRACT
Replication of bovine papillomavirus type 1 (BPV-1) DNA has been shown to require two viral proteins known to interact in a molecular complex E2, a transcription activator, and E1, another nuclear phosphoprotein, which binds to the replication origin and for which helicase/ATPase activities have previously been reported. Here we characterize the BPV-1 E1 ATPase activity. In contrast to Seo et al. (Proceedings of the National Academy of Sciences, USA, 90, 702-706, 1993), we were able to detect this activity in the absence of nucleic acid in partially purified preparations of either E1 protein or of E1-E2 protein complex. Measurements of specific activity and kinetic parameters gave similar values for preparations of various kinds. ATPase activity was quantitatively retained by immunoprecipitates obtained by using anti-E1 or, in the case of E1-E2 complex, anti-E2 antibodies. Significantly, preparations of bacterially expressed glutathione S-transferase-E1 fusion protein exhibited levels of DNA-independent ATPase activity comparable to those of baculovirus-expressed E1. The presence of nucleic acids of various types, including stoichiometric amounts of a BPV-1 ori DNA fragment containing E1 and E2 binding sites, did not grossly affect E1 ATPase activity, the most notable effect being a 2-fold stimulation by unspecific ssDNA. Altogether, our results indicate that BPV-1 E1 possesses an intrinsic ATPase activity which does not depend on the presence of nucleic acid; moreover, they render unlikely any modulation of E1 ATPase activity due to binding either E2 protein or target DNA sequences, or as a result of protein phosphorylation.
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Coleções:
01-internacional
Temas:
Geral
Base de dados:
MEDLINE
Assunto principal:
Proteínas Virais
/
DNA
/
Transativadores
/
Adenosina Trifosfatases
/
Proteínas de Ligação a DNA
/
Papillomavirus Bovino 1
Idioma:
En
Revista:
J Gen Virol
Ano de publicação:
1995
Tipo de documento:
Article
País de afiliação:
França