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Photoaffinity labelling of the mitochondrial uncoupling protein by [ 3 H]azido fatty acid affects the anion channel
Author(s) -
Růžička Michal,
Borecký Jiří,
Hanuš Jan,
Ježek Petr
Publication year - 1996
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(96)00161-5
Subject(s) - thermogenin , uncoupling protein , fatty acid , inner mitochondrial membrane , mitochondrion , labelling , biochemistry , mitochondrial carrier , chemistry , photoaffinity labeling , binding site , brown adipose tissue , bacterial outer membrane , adipose tissue , escherichia coli , gene
Brown adipose tissue (BAT) mitochondria were incubated with the azido derivative of fatty acid (hexadecanoic) containing four tritium atoms, [ 3 H]AzHA, and among all mitochondrial proteins only a few proteins were photolabelled after irradiation with UV. It suggests the existence of specific fatty acid binding sites on mitochondrial proteins. It was also possible to label with [ 3 H]AzHA the isolated uncoupling protein (UcP) of BAT mitochondria with a low stoichiometry — lower than one AzHA per dimeric UcP. These results together with the observed competition (i.e. prevention of photolabelling) of various UcP anionic substrates with [ 3 H]AzHA and its dodecanoic acid analogue, suggest the existence of the specific fatty acid binding site on UcP identical with the anion channel or anion translocating site.