Lin W J, Jakobi R, Traugh J A
Department of Biochemistry, University of California, Riverside 92521.
J Protein Chem. 1994 Feb;13(2):217-25. doi: 10.1007/BF01891979.
Casein kinase II is composed of two catalytic (alpha) and two regulatory (beta) subunits, the amino acid sequences of the alpha and beta subunits are highly conserved between species. To examine whether heterologous casein kinase II could be formed, recombinant alpha and beta subunits from human and Drosophila were reconstituted from inclusion bodies. Casein kinase II containing either human alpha and Drosophila beta or Drosophila alpha and human beta subunits exhibited enzymatic properties similar to those of the homologous holoenzymes with regard to specific activity, salt optima, and autophosphorylation. However, renaturation and reconstitution of casein kinase II was dependent on the type of beta subunits and the redox conditions, with the Drosophila beta subunits requiring more reduced conditions. Chimeric beta subunits prepared from human and Drosophila cDNA revealed that the N-terminal region was responsible for the requirement for the reduced redox state during renaturation. The N-terminal region also affected solubility and electrophoretic mobility of the beta subunit.
酪蛋白激酶II由两个催化（α）亚基和两个调节（β）亚基组成，α亚基和β亚基的氨基酸序列在物种间高度保守。为了检测是否能形成异源酪蛋白激酶II，从包涵体中重构了来自人和果蝇的重组α亚基和β亚基。含有人类α亚基和果蝇β亚基或果蝇α亚基和人类β亚基的酪蛋白激酶II在比活性、最适盐浓度和自身磷酸化方面表现出与同源全酶相似的酶学性质。然而，酪蛋白激酶II的复性和重构取决于β亚基的类型和氧化还原条件，果蝇β亚基需要更还原的条件。由人和果蝇cDNA制备的嵌合β亚基表明，N端区域是复性过程中对还原氧化态需求的原因。N端区域也影响β亚基的溶解性和电泳迁移率。
