Studies on human porin XIX: zinc ions reduce the voltage-dependence of human type-1 porin integrated in artificial planar lipid bilayers; barium ions do not.
We report on the first data concerning the effects of ionic zinc or barium on human type-1 porin. The channel enriched as mature protein from B-lymphocyte crude membranes was integrated into artificial planar lipid bilayers and both agonists were applied as their chloride salts at 100 microM. Relative conductance was measured from -80 to 80 mV. The presence of Zn2+ resulted in a distinct reduction of the voltage dependence of the channel, the effect appearing to be symmetric. The addition of Ba2+ did not produce any measurable effect on human porin. According to our knowledge we present the first results on the interaction of bivalent metal ions and eukaryotic type-1 porin. The putative physiological relevance of the data is discussed.
Hellmann
K P
KP
Department of Immunochemistry, Max-Planck-Institute for Experimental Medicine, Göttingen, Germany.
Siadat
S
S
Reymann
S
S
Thinnes
F P
FP
D001402:B-Lymphocytes; D001464:Barium / Q000378:metabolism* / Q000502:physiology; D002413:Cations, Divalent; D006801:Humans; D015640:Ion Channel Gating; D007473:Ion Channels / Q000378:metabolism* / Q000502:physiology; D008051:Lipid Bilayers / Q000378:metabolism*; D018272:Porins / Q000378:metabolism* / Q000502:physiology; D050995:Voltage-Dependent Anion Channel 1; D015032:Zinc / Q000378:metabolism* / Q000502:physiology
D002413:Cations, Divalent; D007473:Ion Channels; D008051:Lipid Bilayers; D018272:Porins; C494762:VDAC1 protein, human; D001464:Barium; D050995:Voltage-Dependent Anion Channel 1; D015032:Zinc