Ambros, Victor and Baltimore, David (1980) Purification and properties of a HeLa cell enzyme able to remove the 5'- terminal protein from poliovirus RNA. Journal of Biological Chemistry, 255 (14). pp. 6739-6744. ISSN 0021-9258 http://resolver.caltech.edu/CaltechAUTHORS:AMBjbc80
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Using a rapid phenol extraction assay, an enzyme was purified from uninfected HeLa cells that can cleave the 5'-terminal protein (VPg) from poliovirus RNA. Both cytoplasmic and nuclear extracts had enzymes with similar behavior. A polypeptide of molecular weight 27,000 was the major one present in the purified preparation. Assuming that this protein is the enzyme, a very low turnover number was calculated for it. The purified enzyme would cleave the tyrosine-phosphate bond linking VPg to poliovirus RNA with minimal degradation of the RNA or of VPg. If the RNA was first treated with proteinase K to degrade VPg, leaving a small peptide on the RNA, this peptide could also be removed by the enzyme. If the RNA was degraded with T1 RNase, leaving VPg attached to a nonanucleotide, the enzyme still would cleave off VPg, although incompletely. If the RNA was degraded completely, leaving either pUp or pU attached to VPg, the enzyme would not remove the nucleotides from the protein. Thus, for the enzyme to be active requires some length of polynucleotide attached to the protein but only a short peptide need be present for the enzyme to act.
|Additional Information:||Copyright © 1980 by the American Society for Biochemistry and Molecular Biology. (Received for publication, January 14, 1980) This work was supported by Grant A108388 from the National Institutes of Allergy and Infectious Diseases and Grant CA-14051 to S.E. Luna from the National Cancer Institute. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact. [D.B. was an] American Cancer Society Research Professor.|
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|Deposited On:||07 Jan 2007|
|Last Modified:||26 Dec 2012 09:28|
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