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.
European Molecular Biology Laboratory, Heidelberg, Germany.
D N
DN
Wang
W
W
Kühlbrandt
V E
VE
Sarabia
R A
RA
Reithmeier
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