Soluble lactose-binding lectin from rat intestine with two different carbohydrate-binding domains in the same peptide chain.
Soluble lactose-binding lectin from rat intestine with two different carbohydrate-binding domains in the same peptide chain.
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DOI：
10.1016/s0021-9258(18)53409-8
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发表时间：
1993-03
期刊：
影响因子：
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通讯作者：
Yuko OdaST;Jorg Herrmannsq;Michael A. GittS;Christoph W. Turckll;Alma L. Burlingames;Samuel H. BarondesS-Samuel-H.
中科院分区：
文献类型：
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作者：
Yuko OdaST;Jorg Herrmannsq;Michael A. GittS;Christoph W. Turckll;Alma L. Burlingames;Samuel H. BarondesS-Samuel-H.
在大鼠肠道中的多种可溶性乳糖结合（S-Lac）凝集素中，主要的一种暂时命名为RI-H，以前分离为分子量约17，000的多肽。我们在这里报告的RI-H的序列，确定在肽水平和核苷酸水平。令人惊讶的是，cDNA编码分子量约为36，000的蛋白质，并且该蛋白质含有两个同源但不同的结构域，每个结构域具有在所有S-Lac凝集素中保守的序列元件。C-末端结构域，命名为结构域II，对应于先前从肠提取物中分离的M（r）为17，000的凝集素，并显示具有乳糖结合活性。通过制备仅含有N-末端结构域（称为结构域I）的重组蛋白，我们在此直接证明它也结合乳糖和与结构域II大致相似但明显不同的相关范围的糖。我们命名为L-36的新凝集素在大鼠小肠、大肠和胃中以全长形式高度表达，但在其他八种组织（包括肺、肝、肾和脾）中未检测到。每个结构域与另一个结构域以及与L-29（另一种S-Lac凝集素）的碳水化合物结合结构域具有约35%的序列同一性，但与其它已知的S-Lac凝集素仅具有约15%的同一性。
Of the multiple soluble lactose-binding (S-Lac) lectins in rat intestine, the major one, tentatively designated RI-H, was previously isolated as a polypeptide of molecular weight approximately 17,000. We here report the sequence of RI-H, as determined both at the peptide level and at the nucleotide level. Surprisingly the cDNA encodes a protein of molecular weight approximately 36,000, and this protein contains two homologous but distinct domains each with sequence elements that are conserved among all S-Lac lectins. The C-terminal domain, designated domain II, corresponds to the lectin with M(r) of 17,000 previously isolated from intestinal extracts and shown to have lactose binding activity. By preparing recombinant protein containing only the N-terminal domain, designated domain I, we here directly demonstrate that it too binds lactose and a related range of sugars that are roughly similar to domain II, but clearly distinct. The new lectin, which we designate L-36, is highly expressed in full-length form in rat small and large intestine and stomach but was not detected in eight other tissues including lung, liver, kidney, and spleen. Each domain has approximately 35% sequence identity with the other domain and with the carbohydrate-binding domain of L-29, another S-Lac lectin, but only about 15% identity with other known S-Lac lectins.