Novel inter- and intrasubunit contacts between transport-relevant residues of the homodimeric mitochondrial phosphate transport protein.
Novel inter- and intrasubunit contacts between transport-relevant residues of the homodimeric mitochondrial phosphate transport protein.
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同二聚体线粒体磷酸转运蛋白的转运相关残基之间的新型亚基间和亚基内接触。
DOI：
10.1016/j.bbrc.2004.05.211
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
Wohlrab,Hartmut
中科院分区：
文献类型：
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作者：
Wohlrab,Hartmut
Ser 158位于连接线粒体磷酸盐转运蛋白（PTP）的跨膜螺旋C和D的基质环的中间附近。突变的Ser 158 Thr PTP是转运失活的。His 32位于跨膜螺旋A的中间附近，Thr 79位于距离跨膜螺旋B及其N-末端（基质末端）5个残基处。单位点突变PTP的残基被Ala取代是转运失活的。基于牛ADP/ATP转位酶亚基的高分辨率结构，线粒体转运蛋白家族成员之间的序列相似性，以及跨膜A螺旋之间的PTP亚基/亚基接触位点，现在建议Ser 158位点位于PTP亚基/亚基接触位点。这个接触位点对于保持由两个PTP亚基180°异相催化的运输循环是必不可少的。这些数据还表明，His 32和Thr 79的相同的亚基相互作用和耦合的磷酸盐和质子的运输路径。
Ser158 is located near the middle of the matrix loop connecting transmembrane helices C and D of the mitochondrial phosphate transport protein (PTP). The mutant Ser158Thr PTP is transport-inactive. His32 is located near the middle of transmembrane helix A and Thr79 is located 5 residues away from transmembrane helix B and its N-terminal (matrix end). Single site mutant PTPs that have either residue replaced with Ala are transport-inactive. Based on the high resolution structure of a subunit of the bovine ADP/ATP translocase, on sequence similarities between members of the mitochondrial transport protein family, and on the PTP subunit/subunit contact site between transmembrane A helices, it is now suggested that the Ser158 site is at the PTP subunit/subunit contact site. This contact site is essential for keeping the transport cycles catalyzed by the two PTP subunits 180° out of phase. The data also suggest that His32 and Thr79 of the same subunit interact and couple the phosphate and the proton transport paths.