Price A, Economou A, Duong F, Wickner W
Department of Biochemistry, Dartmouth Medical School, Hanover, New Hampshire 03755, USA.
J Biol Chem. 1996 Dec 6;271(49):31580-4. doi: 10.1074/jbc.271.49.31580.
The SecA subunit of preprotein translocase drives ATP-dependent translocation of preproteins across the bacterial inner membrane concomitant with cycles of membrane insertion and de-insertion (Economou, A., and Wickner, W. (1994) Cell 78, 835-843). We have identified the membrane-inserting region of SecA as a 30-kDa domain in the C-terminal third of the protein beginning at aminoacyl residue 610. Limited proteolysis in the absence of translocation ligands indicates that the SecA monomer is composed of two primary structural domains, the 30-kDa membrane-inserting domain and an N-terminal 65-kDa ATPase domain. This limited protease treatment of SecA results in constitutive ATPase activity, indicating that intramolecular constraints between the two domains may play a role in the regulation of ATP hydrolysis by SecA.
前体蛋白转位酶的SecA亚基驱动前体蛋白通过细菌内膜进行ATP依赖性转位，并伴随着膜插入和去插入的循环（Economou, A.和Wickner, W.（1994年）《细胞》78卷，835 - 843页）。我们已将SecA的膜插入区域鉴定为该蛋白质C端三分之一处一个从氨基酰残基610开始的30 kDa结构域。在没有转位配体的情况下进行的有限蛋白酶解表明，SecA单体由两个主要结构域组成，即30 kDa的膜插入结构域和一个N端65 kDa的ATP酶结构域。对SecA进行的这种有限蛋白酶处理导致组成型ATP酶活性，这表明两个结构域之间的分子内限制可能在SecA对ATP水解的调节中起作用。
