The major outer membrane protein of Acidovorax delafieldii is an anion-selective porin.
AUTOR(ES)
Brunen, M
RESUMO
The major outer membrane protein (Omp34) of Acidovorax delafieldii (formerly Pseudomonas delafieldii) was purified to homogeneity and was characterized biochemically and functionally. The polypeptide has an apparent molecular weight (Mr) of 34,000, and it forms stable oligomers at pH 9.0 in the presence of 10% octylpolyoxyethylene or 2% lithium dodecyl sulfate below 70 degrees C. The intact protein has a characteristic secondary structure composition, as revealed by Fourier transforming infrared spectroscopy (about 60% beta sheet). These features and the amino acid composition are typical for porins. The purified Omp34 is associated with 1 to 2 mol of lipopolysaccharide per mol of the monomer. Pore-forming activity was demonstrated with lipid bilayer experiments. Single-channel and selectivity measurements showed that the protein forms highly anion-selective channels. The unusual dependence of the single-channel conductance on salt concentration suggests that the porin complexes bear positive surface charges, accumulating negatively charged counterions at the pore mouth.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=208068Documentos Relacionados
- Bordetella pertussis major outer membrane porin protein forms small, anion-selective channels in lipid bilayer membranes.
- Salmonella typhimurium contains an anion-selective outer membrane porin induced by phosphate starvation.
- Single anion-selective channels in basolateral membrane of a mammalian tight epithelium.
- Escherichia coli outer membrane protein K is a porin.
- Purification of Legionella pneumophila major outer membrane protein and demonstration that it is a porin.
