IMPORTANCE OF LOOPS OF MITOCHONDRIAL ADP/ATP CARRIER FOR ITS TRANSPORT ACTIVITY DEDUCED FROM REACTIVITIES OF ITS CYSTEINE RESIDUES WITH THE SULFHYDRYL REAGENT EOSIN-5-MALEIMIDE
IMPORTANCE OF LOOPS OF MITOCHONDRIAL ADP/ATP CARRIER FOR ITS TRANSPORT ACTIVITY DEDUCED FROM REACTIVITIES OF ITS CYSTEINE RESIDUES WITH THE SULFHYDRYL REAGENT EOSIN-5-MALEIMIDE
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DOI：
10.1021/bi00198a019
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发表时间：
1994-08-16
期刊：
影响因子：
2.9
通讯作者：
TERADA, H
中科院分区：
文献类型：
--
作者：
MAJIMA, E;SHINOHARA, Y;TERADA, H
本文研究了转运底物ADP、转运抑制剂羧甲苷（CATR）和米酵菌酸（BKA）等化合物对巯基试剂曙红-5-马来酰亚胺（EMA）标记牛心脏亚线粒体颗粒ADP/ ATP载体半胱氨酸残基的影响。在载体中的四个半胱氨酸残基中，EMA对Cys（159）的标记主要且快速地进行，Cys（56）和Cys（256）的标记中等地进行，但Cys（128）未被标记，如我们先前报道的[Majima，E.，等人（1993）J.Biol.Chem.268，22181-22187]。ADP抑制EMA对Cys（56）、Cys（159）和Cys（256）的标记。BKA可明显抑制EMA对Cys（159）的标记，也可抑制EMA对Cys（159）的标记。Cys（256），但不影响Cys（56）的标记，表明它从基质侧结合到第二环中靠近Cys（159）的区域，该区域面向基质空间。CATR完全抑制EMA的标记时，添加在胞质侧，但没有效果时，添加在基质侧。从这些结果，载体的构象变化引起的CATR，BKA，和ADP进行了讨论。此外，腺嘌呤核苷酸通过ADP/ATP载体的运输机制与其构象的变化提出。
The effects of various compounds such as the transport substrate ADP and the transport inhibitors carboxyatractyloside (CATR) and bongkrekic acid (BKA) on the labeling of cysteine residues in the ADP/ ATP carrier of bovine heart submitochondrial particles by the SH reagent eosin-5-maleimide (EMA) were studied. Of the four cysteine residues in the carrier, the labeling of Cys(159) by EMA progressed predominantly and rapidly, and those of Cys(56),,d Cys(256) moderately, but Cys(128) was not labeled, as we reported previously [Majima, E., et al. (1993) J. Biol. Chem. 268, 22181-22187]. ADP inhibited the labelings of Cys(56), Cys(159) and Cys(256) by EMA. BKA markedly inhibited the labeling of Cys(159) by EMA, and also the labeling of. Cys(256), but did not affect the labeling of Cys(56) suggesting that it binds from the matrix side to a region close to Cys(159) in the second loop facing the matrix space. CATR completely inhibited the labeling by EMA when added on the cytosolic side, but had no effect when added on the matrix side. From these results, the conformational changes of the carrier induced by CATR, BKA, and ADP are discussed. Furthermore, a mechanism of adenine nucleotide transport through the ADP/ATP carrier in association with change in its conformation is proposed.