Oligomeric structure of bAE3 protein

• Published in: IUBMB life Vol. 50; no. 6; p. 397
• Main Authors: Pushkin, A V, Tsuprun, V L, Abuladze, N K, Newman, D, Kurtz, I
• Format: Journal Article
• Language: English
• Published: England 01.12.2000
• Subjects: Animals; Antiporters - chemistry; Antiporters - genetics; Antiporters - isolation & purification; Chromatography, Affinity; Cloning, Molecular; Kidney - chemistry; Molecular Sequence Data; Octoxynol - chemistry; Protein Conformation; Rabbits
• ISSN: 1521-6543; 1521-6551
• DOI: 10.1080/713803739

The "brain" form of the anion exchanger protein 3 (bAE3) has been purified to homogeneity from the rabbit kidney by differential centrifugation and immunoaffinity chromatography. A single protein band of approximately 165 kDa was detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blotting. Monomers, dimers (a major component), and a higher oligomeric form (apparently tetramers) were found after oxidative cross-linking of purified bAE3. The largest form of bAE3 was separated from dimers and monomers by sucrose gradient centrifugation and was studied by transmission electron microscopy to confirm a tetrameric structure. Two main types of bAE3 images were detected, round (approximately 11-14 nm) and square-shaped (approximately 12 x 12 nm). Image analysis revealed fourfold rotational symmetry of both the round and square-shaped images, indicating that bAE3 consists of multiples of 4 subunits. We conclude that bAE3 in Triton X-100 solution is predominantly a mixture of dimers and tetramers with a smaller amount of monomers.