Monomeric erythrocyte band 3 protein transports anions.
AUTOR(ES)
Lindenthal, S
RESUMO
The anion transport system of the human erythrocyte membrane was reconstituted in egg phosphatidylcholine membranes by using either the unmodified transport protein, band 3, or covalently crosslinked band 3 dimers. Unilamellar vesicles of a diameter of 32 +/- 3 nm were then isolated from the sample by passage through a French press and subsequent gel filtration. According to sedimentation equilibrium measurements, around 85% of the vesicles were devoid of protein. The remaining 15% contained either a single band 3 monomer or, when crosslinked band 3 protein was used, a single band 3 dimer. Vesicles containing either single monomers or single dimers showed a rapid, inhibitor-sensitive sulfate efflux, and the turnover numbers of band 3 for the inhibitor-sensitive flux component were identical in both systems. This shows that monomeric band 3 protein is able to transport anions and that dimerization of the protein does not change its transport activity.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=52122Documentos Relacionados
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