特集2 シンポジウム「立体構造からみたタンパク質の進化」
哺乳類タンパク複合体に見られるサブユニット交換と立体構造の特徴
2009 年 37 巻 4 号 p. 66-72
詳細
2009 年 37 巻 4 号 p. 66-72
How a mechanism of the subunit exchange in a supra-molecular complex does to be a suitable and reasonable form? It seems like to be existing a simple exchange in a complex. However, there are generally so many restrictions on the tertiary structure of the protein folding, for examples hydrogen bonds, hydrophobic and ionic interactions. A mammalian proteasome has two-types complexes, one is constitutive and other immunologic. The immuno-proteasome has six different subunits than constitutive-proteasome, when living cells are in an immune response. How do exchange occur in the complex particle? How and what characteristics in the tertiary structure of the proteasome are existing. We investigated it that contributions of hydrogen bonds among subunits control and form suitable complex by comparing a bovine liver and yeast proteasome, having immune response and no one, respectively.
Contrary to our expectation, yeast proteasome has much hydrogen bonds even if an incorrect subunit exists, rather than a bovine proteasome. The resultant shows bovine proteasome has strict recognition mechanism for incorrect subunits than yeast ones, which may supply possibilities on exchanges of subunits when the immune response occurs in our living cells.
