Mannose transporter of Escherichia coli. Backbone assignments and secondary structure of the IIA domain of the IIABMan subunit

Biochemistry. 1994 Jun 14;33(23):7174-83. doi: 10.1021/bi00189a021.


The mannose transporter of Escherichia coli consists of two transmembrane and one peripheral protein subunit. The complex acts by a mechanism which couples translocation of the substrate with substrate phosphorylation. The peripheral IIABMan is a homodimer. The IIABMan monomer itself contains two domains which are linked by an Ala-Pro-rich hinge and which are both transiently phosphorylated at histidyl residues. The IIA and IIB domains can be separated by limited proteolysis. The IIA domain has a dimer molecular mass of 2 x 14 kDa. Almost complete 1H, 13C, and 15N NMR assignments of the backbone resonances of IIAMan have been achieved using 3D and 4D double-and triple-resonance techniques. Secondary structure elements were derived from NOE data. The IIA domain consists of a central beta-sheet of four parallel and one antiparallel strand (strand order 5 4 3 1 2) with helices on both sides of the sheet. The active-site His-10 is located in a loop at the C-terminus of beta-strand 1. This loop and the loop after strand 3 are at the topological switch point of the sheet.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • Biological Transport
  • Carrier Proteins / chemistry*
  • Carrier Proteins / metabolism
  • Escherichia coli / chemistry*
  • Escherichia coli / metabolism
  • Magnetic Resonance Spectroscopy
  • Mannose / metabolism*
  • Mannose-Binding Lectins
  • Molecular Sequence Data
  • Oligodeoxyribonucleotides
  • Phosphoenolpyruvate Sugar Phosphotransferase System / metabolism
  • Protein Structure, Secondary*


  • Carrier Proteins
  • Mannose-Binding Lectins
  • Oligodeoxyribonucleotides
  • Phosphoenolpyruvate Sugar Phosphotransferase System
  • Mannose

Associated data

  • GENBANK/X66059