Uncoupling protein, H+ transport and regulation.
The biochemical functions of uncoupling proteins (UCPs) are discussed with the view of UCP1 as a paradigm. In contrast with UCP1, the heterologous expression of UCP3 in yeast is found to result primarily in extra-mitochondrial deposits and thus is unsuitable for studying UCP3 function. On expression in Escherichia coli inclusion bodies, UCPs extracted and incorporated into vesicles showed no H(+) transport, only Cl(-) transport. Only after addition of coenzyme Q was fully nucleotide-sensitive high-H(+) transport reconstituted, with UCP1 as well as with UCP2 and UCP3. The newly discovered cofactor role of coenzyme Q in H(+) transport is proposed to imply co-operation with fatty acids for the injection of H(+) into the UCP channel.
Klingenberg
M
M
Institute of Physical Biochemistry, University of Munich, Schillerstrasse 44, D-80336 Munich, Germany. klingenberg@pbm.med.uni-muenchen.de
Winkler
E
E
Echtay
K
K
D000255:Adenosine Triphosphate / Q000378:metabolism; D001692:Biological Transport; D002352:Carrier Proteins / Q000378:metabolism* / Q000502:physiology*; D004926:Escherichia coli / Q000378:metabolism; D007473:Ion Channels; D008565:Membrane Proteins / Q000378:metabolism* / Q000502:physiology*; D008928:Mitochondria / Q000378:metabolism; D024101:Mitochondrial Proteins; D008954:Models, Biological; D011522:Protons; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D014451:Ubiquinone / Q000378:metabolism; D000071256:Uncoupling Protein 1
D002352:Carrier Proteins; D007473:Ion Channels; D008565:Membrane Proteins; D024101:Mitochondrial Proteins; D011522:Protons; D000071256:Uncoupling Protein 1; D014451:Ubiquinone; D000255:Adenosine Triphosphate