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标题：Difference between Yeast and Bovine Mitochondrial ADP/ATP Carriers in Terms of Conformational Properties of the First Matrix Loop as Deduced by Use of Copper-o-phenanthroline
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作者：Yoshitaka Kihira ; Masaharu Ueno ; Hiroshi Terada 等
期刊名称：Biological and Pharmaceutical Bulletin
印刷版ISSN：0918-6158
电子版ISSN：1347-5215
出版年度：2007
卷号：30
期号：5
页码：885-890
DOI：10.1248/bpb.30.885
出版社：The Pharmaceutical Society of Japan
摘要：The mitochondrial ADP/ATP carrier (AAC) has 6 transmembrane regions and 3 matrix loops. Our previous mutational study on the Cys residue in the LM1s of chimeric bovine type 1 AAC (yN-bAAC1), in which the N-terminal 11 amino acids of bovine type 1 AAC are substituted with the corresponding 26 amino acids of yeast type 2 AAC (yAAC2), and yAAC2 in the yeast expression system suggested the possibility of a different structural feature between their LM1s. In the present study, we compared the effects of the SH cross-linking reagent copper- o -phenanthroline (Cu(OP)₂) on yN-bAAC1 and yAAC2 in order to study the difference between these LM1s of the 2 carriers. Cu(OP)₂ is known to cross-link 2 AAC molecules in a functional dimer via a Cys residue in each first matrix loop (LM1). yN-bAAC1 exhibited intra- and inter-molecular cross-linking, in agreement with the results of a previous study on the native bovine carrier and suggesting that yN-bAAC1 had the same structure as the native carrier. yAAC2 also showed intra- and inter-molecular cross-linking. However, the speed of formation of the inter-molecular cross-linking of yN-bAAC1 was faster than that of yAAC2, suggesting that the conformational state of the LM1 was different between the 2 carriers. In addition, we also studied the effects of AAC-specific inhibitors and solubilization with Triton X-100 on the cross-linking.
关键词：ADP/ATP carrier;conformation;loop;membrane protein;mitochondria