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Two‐dimensional structure of the membrane domain of human band 3, the anion transport protein of the erythrocyte membrane.
Author(s) -
Wang D.N.,
Kühlbrandt W.,
Sarabia V.E.,
Reithmeier R.A.
Publication year - 1993
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1993.tb05876.x
Subject(s) - band 3 , biology , erythrocyte membrane , membrane protein , transport protein , membrane , biophysics , membrane transport protein , protein structure , domain (mathematical analysis) , membrane transport , microbiology and biotechnology , biochemistry , mathematical analysis , mathematics
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 × 50 A in projection), surrounding a central depression. The third subdomain of the monomer measures approximately 15 × 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.