The Amino Acid-Polyamine-Organocation Superfamily
The Amino Acid-Polyamine-Organocation Superfamily
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DOI：
10.1159/000338542
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发表时间：
2012-05
影响因子：
1.2
通讯作者：
F. Wong;Jonathan S. Chen;V. Reddy;Jonathan L. Day;Maksim A. Shlykov;Steven T. Wakabayashi;M. Saier Jr.
中科院分区：
文献类型：
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作者：
F. Wong;Jonathan S. Chen;V. Reddy;Jonathan L. Day;Maksim A. Shlykov;Steven T. Wakabayashi;M. Saier Jr.
氨基酸-多胺-有机配位（APC）超家族已被证明包括五个公认的家族，其中四个是氨基酸及其衍生物的特异性家族。最近的高分辨率x射线晶体学数据显示，另外四个转运蛋白家族(BCCT, TC 2.A.15； SSS, 2.A.21； NSS, 2.A.22；39)，运输广泛的溶质，表现出足够相似的褶皱，表明一个共同的进化起源。我们使用基于序列相似性的既定统计方法来显示这些家族实际上是APC超家族的成员。我们还确定了另外两个家族（NCS2, 2.A.40; SulP, 2.A.40）。53)作为这个超级家族的成员。重复序列，每个具有五个跨膜α-螺旋片段，并通过古老的基因内复制产生，证明了所有这些家族的同源性，进一步加强了同源性的结论。APC超家族似乎是二级载体的第二大超家族，最大的是主要促进者超家族（MFS）。尽管APC超家族成员的拓扑结构与MFS不同，但这两个家族似乎都起源于共同的祖先2 TMS发夹结构，该结构经历了基因内三倍复制，随后APC家族中TMS缺失，从而产生了这两个超家族特有的重复单元。
The amino acid-polyamine-organocation (APC) superfamily has been shown to include five recognized families, four of which are specific for amino acids and their derivatives. Recent high-resolution X-ray crystallographic data have shown that four additional transporter families (BCCT, TC No. 2.A.15; SSS, 2.A.21; NSS, 2.A.22; and NCS1, 2.A.39), transporting a wide range of solutes, exhibit sufficiently similar folds to suggest a common evolutionary origin. We have used established statistical methods, based on sequence similarity, to show that these families are, in fact, members of the APC superfamily. We also identify two additional families (NCS2, 2.A.40; SulP, 2.A.53) as being members of this superfamily. Repeat sequences, each having five transmembrane α-helical segments and arising via ancient intragenic duplications, are demonstrated for all of these families, further strengthening the conclusion of homology. The APC superfamily appears to be the second largest superfamily of secondary carriers, the largest being the major facilitator superfamily (MFS). Although the topology of the members of the APC superfamily differs from that of the MFS, both families appear to have arisen from a common ancestral 2 TMS hairpin structure that underwent intragenic triplication followed by loss of a TMS in the APC family, to give the repeat units that are characteristic of these two superfamilies.