Characterization of channel-forming activity in muscle biopsy from a porin-deficient human patient.
A bioptic specimen from the muscles of a patient suffering from severe myopathy was inspected for the presence of human porin 31HL. Western blotting suggested that the specimen was free of the most abundant eukaryotic porin 31HL (HVDAC1). The specimen was treated with detergent and the soluble protein fraction was passed through a dry hydroxyapatite column. The passthrough of this column was inspected for channel formation in artificial lipid-bilayer membranes. The channel observed under these conditions had a single-channel conductance of about 2.5 nS in 1 M KCl, was cation selective, and was found to be virtually voltage independent. Experiments with a control specimen from a healthy human being, without any indication for muscle myopathy, revealed the presence of the voltage-dependent porin 31HL in the sample. It is discussed whether the patient's bioptic specimen contained another human porin, which has not been studied to date in its natural environment.
De Pinto
V
V
Department of Chemical Sciences, Laboratory of Biochemistry and Molecular Biology, Università di Catania, viale A. Doria 6, I-95125 Catania, Italy. vdpbiofa@mbox.unict.it
Messina
A
A
Schmid
A
A
Simonetti
S
S
Carnevale
F
F
Benz
R
R
D001706:Biopsy; D015153:Blotting, Western; D016022:Case-Control Studies; D002675:Child, Preschool; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D066298:In Vitro Techniques; D008051:Lipid Bilayers; D008297:Male; D008564:Membrane Potentials; D009132:Muscles / Q000378:metabolism; D009135:Muscular Diseases / Q000235:genetics / Q000378:metabolism*; D050995:Voltage-Dependent Anion Channel 1 / Q000172:deficiency* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism
D008051:Lipid Bilayers; C494762:VDAC1 protein, human; D050995:Voltage-Dependent Anion Channel 1