title: Biophysical and biochemical characterization of recombinant human Pop2 deadenylase.
abstract: Pop2, a component of the Ccr4-Not complex, functions as a deadenylase both in vitro and in vivo. In this research, we found that the recombinant human Pop2 (hPop2) mainly existed in a compact monomeric state with a a + b tertiary structure type. The percentages of the secondary structures evaluated from the CD spectrum were about 37% a-helix, 14% b-sheet, and 19% b-turns. The optimal condition for hPop2 catalysis was pH 7-8 at 37 C. Mg2+, Mn2+, and Co2+ had similar effects on the deadenylation activity of hPop2, and the optimal concentration was 0.3-0.5 mM. The deadenylase activity of hPop2 was, at least partially, specific when coordinated with divalent metal ions. The enzyme was not inhibited much by the nucleotide analogs, and the product 50-AMP was the most efficient inhibitor. The dissimilarity in the metal ion dependence and inhibitory effects of the nucleotide analogs suggested that various deadenylases might have differential regulation mechanisms.
authors.affiliation: State Key Laboratory of Biomembrane and Membrane Biotechnology, Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing 100084, PR China.
authors.forename: Wei-Feng
authors.initials: WF
authors.lastname: Liu
authors.forename: Yong-Bin
authors.initials: YB
authors.lastname: Yan
mesh_terms: D002384:Catalysis; D002413:Cations, Divalent; D003035:Cobalt; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008274:Magnesium; D008345:Manganese; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D014157:Transcription Factors / Q000737:chemistry / Q000378:metabolism*
chemical_list: C489780:CNOT8 protein, human; D002413:Cations, Divalent; D011994:Recombinant Proteins; D014157:Transcription Factors; D003035:Cobalt; D008345:Manganese; D008274:Magnesium