Two-dimensional structure of the membrane domain of human band 3, the anion transport protein of the erythrocyte membrane.
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.
Wang
D N
DN
European Molecular Biology Laboratory, Heidelberg, Germany.
Kühlbrandt
W
W
Sarabia
V E
VE
Reithmeier
R A
RA
D001457:Anion Exchange Protein 1, Erythrocyte / Q000737:chemistry* / Q000378:metabolism / Q000648:ultrastructure; D001692:Biological Transport; D003460:Crystallization; D004910:Erythrocyte Membrane / Q000737:chemistry*; D006801:Humans; D008854:Microscopy, Electron; D011487:Protein Conformation
D001457:Anion Exchange Protein 1, Erythrocyte