Molecular cloning, characterization, and differential expression pattern of mouse lung surfactant convertase
Molecular cloning, characterization, and differential expression pattern of mouse lung surfactant convertase
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DOI：
10.1152/ajplung.1998.275.5.l969
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发表时间：
1998-11-01
影响因子：
4.9
通讯作者：
Gross, NJ
中科院分区：
文献类型：
--
作者：
Krishnasamy, S;Teng, AL;Gross, NJ
我们最近报道了“表面活性剂转化酶”的纯化和部分氨基酸序列，这是一种参与肺表面活性剂细胞外代谢的 72 kDa 糖蛋白（S. Krishnasamy、N. J. Gross、A. L. Teng、R. M. Schultz 和 R. Dhand. Biochem. Biophys. Res. Commun. 235: 180-184, 1997）。我们在这里报告从小鼠肺 cDNA 文库中分离出编码假定转化酶的 cDNA 克隆。该 cDNA 涵盖 1,836 bp 序列，具有编码成熟蛋白中 536 个氨基酸残基的开放阅读框和位于 NH2 末端的 18 个氨基酸信号肽。推导的氨基酸序列与先前从纯化蛋白质中获得的四个部分氨基酸序列（68 个残基）相匹配。推导的氨基酸序列包含一个18个氨基酸残基的信号肽、一个丝氨酸活性位点共有序列、一个组氨酸共有序列、五个潜在的N联糖基化位点和一个COOH末端分泌型序列His-Thr-Glu-His-Lys。引物延伸分析表明转录从起始密码子上游 29 个核苷酸处开始。对从不同小鼠器官中分离的 RNA 进行的 Northern 印迹分析表明，转化酶在肺、肾和肝脏中以 1,800 个核苷酸长的转录本表达。推定的转化酶的核苷酸和氨基酸序列与小鼠肝脏羧酸酯酶有98%的同源性。因此，它可能是在肺实质中表达的羧酸酯酶家族(EC 3.1.1.1)的第一个成员，并且是第一个具有已知生理功能的成员。
We recently reported the purification and partial amino acid sequence of "surfactant convertase," a 72-kDa glycoprotein involved in the extracellular metabolism of lung surfactant (S. Krishnasamy, N. J. Gross, A. L. Teng, R. M. Schultz, and R. Dhand. Biochem. Biophys. Res. Commun. 235: 180-184, 1997). We report here the isolation of a cDNA clone encoding putative convertase from a mouse lung cDNA library. The cDNA spans a 1,836-bp sequence, with an open reading frame encoding 536 amino acid residues in the mature protein and an 18-amino acid signal peptide at the NH2 terminus. The deduced amino acid sequence matches the four partial amino acid sequences (68 residues) that were previously obtained from the purified protein. The deduced amino acid sequence contains an 18-amino acid residue signal peptide, a serine active site consensus sequence, a histidine consensus sequence, five potential N-linked glycosylation sites, and a COOH-terminal secretory-type sequence His-Thr-Glu-His-Lys. Primer-extension analysis revealed that transcription starts 29 nucleotides upstream from the start codon. Northern blot analysis of RNA isolated from various mouse organs showed that convertase is expressed in lung, kidney, and liver as a 1,800-nucleotide-long transcript. The nucleotide and amino acid sequences of putative convertase are 98% homologous with mouse liver carboxylesterase. It thus may be the first member of the carboxylesterase family (EC 3.1.1.1)to be expressed in lung parenchyma and the first with a known physiological function.