Two-dimensional structure of the membrane domain of human band 3, the anion transport protein of the erythrocyte membrane

EMBO J. 1993 Jun;12(6):2233-9.

Abstract

The membrane domain of human erythrocyte Band 3 protein (M(r) 52,000) was reconstituted with lipids into two-dimensional crystals in the form of sheets or tubes. Crystalline sheets were monolayers with six-fold symmetry (layer group p6, a = b = 170 A, gamma = 60 degrees), whereas the symmetry of the tubular crystals was p2 (a = 104 A, b = 63 A, gamma = 104 degrees). Electron image analysis of negatively stained specimens yielded projection maps of the protein at 20 A resolution. Maps derived from both crystal forms show that the membrane domain is a dimer of two monomers related by two-fold symmetry, with each monomer consisting of three subdomains. In the dimer, two subdomains of each monomer form a roughly rectangular core (40 x 50 A in projection), surrounding a central depression. The third subdomain of the monomer measures approximately 15 x 25 A in projection and appears to be connected to the other two by a flexible link. We propose that the central depression may represent the channel for anion transport while the third subdomain appears not to be directly involved in channel formation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anion Exchange Protein 1, Erythrocyte / chemistry*
  • Anion Exchange Protein 1, Erythrocyte / metabolism
  • Anion Exchange Protein 1, Erythrocyte / ultrastructure
  • Biological Transport
  • Crystallization
  • Erythrocyte Membrane / chemistry*
  • Humans
  • Microscopy, Electron
  • Protein Conformation

Substances

  • Anion Exchange Protein 1, Erythrocyte