The Escherichia coli twin-arginine translocase: conserved residues of TatA and TatB family components involved in protein transport.
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.
Hicks
Matthew G
MG
Department of Molecular Microbiology, John Innes Centre, Norwich NR4 7UH, UK.
de Leeuw
Erik
E
Porcelli
Ida
I
Buchanan
Grant
G
Berks
Ben C
BC
Palmer
Tracy
T
D000595:Amino Acid Sequence; D001665:Binding Sites; D002462:Cell Membrane / Q000378:metabolism; D017124:Conserved Sequence; D004926:Escherichia coli; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010089:Oxidoreductases, N-Demethylating / Q000378:metabolism; D021381:Protein Transport; D016415:Sequence Alignment
D029968:Escherichia coli Proteins; D026901:Membrane Transport Proteins; C499697:TatA protein, E coli; C473116:TatB protein, E coli; C408585:twin-arginine translocase complex, E coli; D010089:Oxidoreductases, N-Demethylating; C023186:trimethylamine dehydrogenase