Mitochondria-derived and extra-mitochondrial human type-1 porin are identical as revealed by amino acid sequencing and electrophysiological characterisation.
In mammalian cells porin channels are localised in both mitochondrial outer membranes and extra-mitochondrial membranes. We isolated mitochondria-derived porin of a human lymphoblastoid B cell line, determined its amino acid sequence and characterised its channel properties. Interestingly, the amino acid sequence of this porin preparation and, correspondingly, its electrophysiological characteristics in a reconstituted system were identical to those of 'Porin 31HL', the human type-1 porin purified from a crude membrane preparation of the same cell line using a different purification protocol. The results raise questions about targeting, insertion and orientation of human type-1 porin in different membranes.
Stadtmüller
U
U
Max-Planck-Institut für experimentelle Medizin, Abteilung Immunchemie, Göttingen, Germany.
Eben-Brunnen
J
J
Schmid
A
A
Hesse
D
D
Klebert
S
S
Kratzin
H D
HD
Hesse
J
J
Zimmermann
B
B
Reymann
S
S
Thinnes
F P
FP
Benz
R
R
Götz
H
H
Hilschmann
N
N
D000595:Amino Acid Sequence; D006801:Humans; D008564:Membrane Potentials / Q000502:physiology; D008969:Molecular Sequence Data; D018272:Porins / Q000737:chemistry* / Q000502:physiology; D017386:Sequence Homology, Amino Acid; D050995:Voltage-Dependent Anion Channel 1; D050994:Voltage-Dependent Anion Channels
D018272:Porins; C494762:VDAC1 protein, human; D050994:Voltage-Dependent Anion Channels; D050995:Voltage-Dependent Anion Channel 1