Mitochondria-derived and extra-mitochondrial human type-1 porin are identical as revealed by amino acid sequencing and electrophysiological characterisation.
Stadtmüller U,
Eben-Brunnen J,
Schmid A,
Hesse D,
Klebert S,
Kratzin HD,
Hesse J,
Zimmermann B,
Reymann S,
Thinnes FP,
Benz R,
Götz H,
Hilschmann N.
Max-Planck-Institut für experimentelle Medizin, Abteilung Immunchemie, Göttingen, Germany.
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.
PMID: 10661876 [PubMed - indexed for MEDLINE]