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|Type:||Artigo de periódico|
|Title:||Photoaffinity Labeling Of The Nucleotide-binding Site Of The Uncoupling Protein From Potato Tuber Mitochondria|
Silva Jr. A.
|Abstract:||In the present work the nurleotide binding .site of ihe uncoupling protein from potato tuber mitochondria (PUMP) was probed bv photoaffinity labeling with 8-azido-ATP. An adenine nurleotide binding site is described which is distinct from the one present in the ADP/ATP carrier (AAC). This adenine nucleotide binding site is sensitive to CTP with a dissociation constant for 8-azido-ATP of 21 /iM and an optimum at acidic pH. The GTP sensitivity and pH dependence of the adenine nucleotide binding site detected in potato tuber mitochondria (PM) was not apparent in rat iivor mitochondria (KLM), and closely corresponds to the uncoupling protein (I'CP) of brown adipose tissue mitochondria (BATM). Photoaffinity labeling of potato mitochondria with 8azido-ATP showed incorporation of the probe into a protein with an apparent Mr 32,000, and a second one with an apparent Mr 30,000. These proteins would correspond to PUMP and AAC, since labeling was prevented by GTP or CAT, respectively. Similar results were obtained with BATM that contain UCP, but not with RLM that is devoid of this protein. These results show that many of the characteristics of PUMP resemble those presented by UCP of BATM. These observations address to the need of an in-depth revision of the proposed mechanism on the evolution of this protein in nature.|
|Appears in Collections:||Unicamp - Artigos e Outros Documentos|
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