Protein AQ_1862 from the hyperthermophilic bacterium Aquifex aeolicus is a porin and contains two conductance pathways of different selectivity.

ABSTRACT: The "hypothetical protein" AQ_1862 was isolated from the membrane fraction of Aquifex aeolicus and identified as the major porin. In experiments with one conducting unit (molecule) a conductance of 1.4 nS was observed in 0.1 M KCl at pH 7.5. This stable (basic) conductance was superimposed by conductance fluctuations of approximately 0.25 nS. Because both events were always observed simultaneously, it is suggested that they are caused by the same molecular entity. Nonetheless they show very different properties. The basic conductance is anion selective at neutral pH with a conductance sequence Cl- approximately Br- approximately NO3->F->gluconate approximately acetate approximately propionate and does not saturate up to 0.5 M KCl. At alkaline pH and in the presence of large anions, it beco

SUBMITTER: Wedemeyer U 

PROVIDER: S-EPMC1989714 | biostudies-literature | 2007 Oct

REPOSITORIES: biostudies-literature