Snyders S, Ramamurthy V, Oliver D
Department of Molecular Biology and Biochemistry, Wesleyan University, Middletown, Connecticut 06459, USA.
J Biol Chem. 1997 Apr 25;272(17):11302-6. doi: 10.1074/jbc.272.17.11302.
SecA ATPase promotes Escherichia coli protein translocation by its association with the preprotein or preprotein-SecB complex, anionic phospholipids, and the other core component of translocase, integral membrane protein SecYEG. Using ligand affinity blotting we demonstrate a direct interaction of SecA with SecY protein. Proteolysis and gene truncation or fusion studies were used to further define this interaction. Our results demonstrate that the carboxyl-terminal third of SecA protein binds to the amino-terminal 107 amino acid residues of SecY protein. The direct demonstration of these interactions culminate studies that have inferred an interaction between SecA and SecYEG, and they are consistent with studies suggesting that this region of SecA interacts with the inner membrane.
SecA ATP酶通过与前体蛋白或前体蛋白 - SecB复合物、阴离子磷脂以及转位酶的另一个核心组分——整合膜蛋白SecYEG相结合，来促进大肠杆菌中的蛋白质转运。我们利用配体亲和印迹法证明了SecA与SecY蛋白之间存在直接相互作用。通过蛋白水解以及基因截短或融合研究进一步确定了这种相互作用。我们的结果表明，SecA蛋白的羧基末端三分之一区域与SecY蛋白的氨基末端107个氨基酸残基相结合。这些相互作用的直接证明完善了那些推断SecA与SecYEG之间存在相互作用的研究，并且与表明SecA的这一区域与内膜相互作用的研究结果相符。
