A novel and ubiquitous system for membrane targeting and secretion of cofactor-containing proteins

Cell. 1998 Apr 3;93(1):93-101. doi: 10.1016/s0092-8674(00)81149-6.


We report the identification of the proteins encoded by the mttABC operon (formerly yigTUW), which mediate a novel Sec-independent membrane targeting and translocation system in Escherichia coli that interacts with cofactor-containing redox proteins having a S/TRRXFLK "twin arginine" leader motif. A pleiotropic-negative mutant in mttA prevents the periplasmic localization of twin arginine redox enzymes, including nitrate reductase (NapA) and trimethylamine N-oxide reductase (TorA). The mutation also prevents the correct localization of the integral membrane molybdoenzyme dimethylsulfoxide reductase (DmsABC). The DmsA subunit has a twin arginine leader. Proteins with a Sec-dependent leader or which assemble spontaneously in the membrane are not affected by this mutation. MttA, B, and C are members of a large family of related sequences extending from archaebacteria to higher eukaryotes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 2S Albumins, Plant
  • Amino Acid Sequence
  • Arginine / metabolism
  • Cell Membrane / enzymology
  • Cloning, Molecular
  • Escherichia coli / genetics
  • Escherichia coli / growth & development
  • Escherichia coli / metabolism*
  • Escherichia coli Proteins
  • Genotype
  • Iron-Sulfur Proteins*
  • Kinetics
  • Membrane Proteins / biosynthesis*
  • Membrane Proteins / chemistry
  • Membrane Proteins / genetics
  • Membrane Transport Proteins*
  • Molecular Sequence Data
  • NADH, NADPH Oxidoreductases / metabolism*
  • Nitrate Reductase
  • Nitrate Reductases / metabolism*
  • Operon*
  • Oxidoreductases / metabolism*
  • Oxidoreductases Acting on CH-NH Group Donors
  • Plant Proteins / metabolism*
  • Plasmids
  • Polymerase Chain Reaction
  • Protein Sorting Signals / chemistry
  • Protein Structure, Secondary
  • Recombinant Proteins / biosynthesis
  • Recombinant Proteins / chemistry
  • Sequence Alignment


  • 2S Albumins, Plant
  • Escherichia coli Proteins
  • Iron-Sulfur Proteins
  • Membrane Proteins
  • Membrane Transport Proteins
  • Plant Proteins
  • Protein Sorting Signals
  • Recombinant Proteins
  • napin protein, Brassica napus
  • Arginine
  • Oxidoreductases
  • methylamine dehydrogenase
  • Oxidoreductases Acting on CH-NH Group Donors
  • NADH, NADPH Oxidoreductases
  • Nitrate Reductases
  • Nitrate Reductase
  • napA protein, E coli
  • dimethyl sulfoxide reductase

Associated data

  • GENBANK/AF067848