Hicks Matthew G, de Leeuw Erik, Porcelli Ida, Buchanan Grant, Berks Ben C, Palmer Tracy
Department of Molecular Microbiology, John Innes Centre, Norwich NR4 7UH, UK.
FEBS Lett. 2003 Mar 27;539(1-3):61-7. doi: 10.1016/s0014-5793(03)00198-4.
The Escherichia coli Tat system serves to export folded proteins harbouring an N-terminal twin-arginine signal peptide across the cytoplasmic membrane. In this report we have studied the functions of conserved residues within the structurally related TatA and TatB proteins. Our results demonstrate that there are two regions within each protein of high sequence conservation that are critical for efficient Tat translocase function. The first region is the interdomain hinge between the transmembrane and the amphipathic alpha-helices of TatA and TatB proteins. The second region is within the amphipathic helices of TatA and TatB. In particular an invariant phenylalanine residue within TatA proteins is essential for activity, whereas a string of glutamic acid residues on the same face of the amphipathic helix of TatB is important for function.
大肠杆菌双精氨酸转运（Tat）系统用于将携带N端双精氨酸信号肽的折叠蛋白转运穿过细胞质膜。在本报告中，我们研究了结构相关的TatA和TatB蛋白中保守残基的功能。我们的结果表明，每种蛋白内有两个高度序列保守的区域，它们对Tat转位酶的高效功能至关重要。第一个区域是TatA和TatB蛋白跨膜螺旋与两亲性α螺旋之间的结构域间铰链。第二个区域在TatA和TatB的两亲性螺旋内。特别是TatA蛋白内一个不变的苯丙氨酸残基对活性至关重要，而TatB两亲性螺旋同一面上的一串谷氨酸残基对功能很重要。
