The Entire N-Terminal Half of TatC is Involved in Twin-Arginine Precursor Binding

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• 作者：Eva Holzapfel ; Gottfried Eisner ; Meriem Alami ; Claire M. L. Barrett ; Grant Buchanan ; Iris Lü ; ke ; Jean-Michel Betton ; Colin Robinson ; Tracy Palmer ; Michael Moser ; Matthias Mü ; ller
• 刊名：Biochemistry
• 出版年：2007
• 出版时间：March 13, 2007
• 年：2007
• 卷：46
• 期：10
• 页码：2892 - 2898
• 全文大小：366K
• 年卷期：v.46,no.10(March 13, 2007)
• ISSN：1520-4995

文摘

Translocation of twin-arginine precursor proteins across the cytoplasmic membrane ofEscherichia coli requires the three membrane proteins TatA, TatB, and TatC. TatC and TatB were shownto be involved in precursor binding. We have analyzed in vitro a number of single alanine substitutionsin tatC that were previously shown to compromise in vivo the function of the Tat translocase. All tatCmutants that were defective in precursor translocation into cytoplasmic membrane vesicles concomitantlyinterfered with precursor binding not only to TatC but also to TatB. Hence structural changes of TatCthat affect precursor targeting simultaneously abolish engagement of the twin-arginine signal sequencewith TatB and block the formation of a functional Tat translocase. Since these phenotypes were observedfor tatC mutations spread over the first half of TatC, this entire part of the molecule must globally beinvolved in precursor binding.