THE SUCRASE-ISOMALTASE COMPLEX - PRIMARY STRUCTURE, MEMBRANE-ORIENTATION, AND EVOLUTION OF A STALKED, INTRINSIC BRUSH-BORDER PROTEIN
THE SUCRASE-ISOMALTASE COMPLEX - PRIMARY STRUCTURE, MEMBRANE-ORIENTATION, AND EVOLUTION OF A STALKED, INTRINSIC BRUSH-BORDER PROTEIN
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DOI：
10.1016/0092-8674(86)90739-7
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发表时间：
1986-07-18
期刊：
影响因子：
64.5
通讯作者：
LODISH, HF
中科院分区：
文献类型：
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作者：
HUNZIKER, W;SPIESS, M;LODISH, HF
从兔小肠蔗糖酶-异麦芽糖酶原（pro-SI）的近全长cDNA序列中推导出其完整的一级结构（1827个氨基酸）。Pro-SI通过仅一次跨越双层的单个20个氨基酸区段锚定在膜中。氨基末端的胞质结构域由12个氨基酸组成，并且前面没有切割的前导序列。这表明跨膜片段作为膜插入的未切割信号具有双重作用。随后是富含22个残基的丝氨酸/苏氨酸的、可能糖基化的延伸，推测形成柄，球状催化结构域在该柄上被引导到肠腔中。随后是异麦芽糖酶和蔗糖酶部分之间的高度同源性（41%氨基酸同一性），表明pro-SI通过部分基因复制进化。
The complete primary structure (1827 amino acids) of rabbit intestinal pro-sucrase-isomaltase (pro-SI) was deduced from the sequence of a nearly full-length cDNA. Pro-SI is anchored in the membrane by a single 20 amino acid segment spanning the bilayer only once. The amino-terminal, cytoplasmic domain consists of 12 amino acids and is not preceded by a cleaved leader sequence. This suggests a dual role for the membrane-spanning segment as an uncleaved signal for membrane insertion. This is followed by a 22 residue serine/threonine-rich, probably glycosylated, stretch, presumably forming the stalk on which the globular, catalytic domains are directed into the intestinal lumen. Following this is a high degree of homology between the isomaltase and sucrase portions (41% amino acid identity), indicating that pro-SI evolved by partial gene duplication.