Biophysical and biochemical characterization of recombinant human Pop2 deadenylase.
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.
Liu
Wei-Feng
WF
State Key Laboratory of Biomembrane and Membrane Biotechnology, Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing 100084, PR China.
Yan
Yong-Bin
YB
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*
C489780:CNOT8 protein, human; D002413:Cations, Divalent; D011994:Recombinant Proteins; D014157:Transcription Factors; D003035:Cobalt; D008345:Manganese; D008274:Magnesium