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Free keywords:
Escherichia-coli porins; Lipid bilayer-membranes; Outer-membrane; Acidovorax-delafieldii; Functional-characterization; Rhodopseudomonas-blastica; Paracoccus-denitrificans; Electrostatic properties; Electrical properties; One conformation.; Biochemistry & biophysics.
Abstract:
The open channel characteristics of the bacterial porin Omp32 from Comamonas acidovorans were investigated by means of conductance measurements in planar lipid bilayers of the Montal-Mueller type. Particularly at low salt conditions (less than or equal to 30 mM KCI) Omp32 exhibited some unusual asymmetric and nonlinear functional properties. Current-voltage relationship measurements showed that conductance depends on the orientation of porin molecules and is a nonlinear function of the applied membrane potential. Conductance also depends on the salt concentration in a manner not common to porins and the salt concentration modulates the nonlinearity of conductance-voltage relationships. Omp32 is strongly anion-selective. The nonlinear and asymmetric conductance of the open channel is a new observation in porins. [References: 44]
