Complete primary structures of two major murine serum amyloid A proteins deduced from cDNA sequences.
Complete primary structures of two major murine serum amyloid A proteins deduced from cDNA sequences.
复制标题
从 cDNA 序列推导出的两种主要鼠血清淀粉样蛋白 A 的完整一级结构。
DOI：
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发表时间：
1985
影响因子：
11.1
通讯作者：
S. Migita
中科院分区：
文献类型：
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作者：
K. Yamamoto;S. Migita
从脂多糖刺激的 BALB/c 小鼠的肝脏 cDNA 文库中分离出编码两种主要小鼠血清淀粉样蛋白 A 蛋白 SAA1 和 SAA2 的 cDNA 克隆，并测定了它们的核苷酸序列。 SAA2 cDNA克隆的插入片段含有607个核苷酸，其中包含36个核苷酸的5'非翻译区、对应于19个氨基酸的信号肽区、对应于103个氨基酸的成熟蛋白区和202个核苷酸的3'非翻译区。 SAA1 cDNA 插入片段包含 549 个核苷酸，指定信号肽区域、成熟蛋白区域和 3' 非翻译区域的一部分。 SAA1 cDNA 与 SAA2 cDNA 的核苷酸序列和推导的氨基酸序列的比较显示出高度的同源性：编码区中的核苷酸序列同源性为 95%（氨基酸序列同源性为 91%），3'非翻译区中的同源性为 90%。从cDNA序列预测的SAA1和SAA2之间的九个氨基酸差异之一位于淀粉样蛋白A形成的推定蛋白水解切割位点：SAA2在该位点具有Thr-Met序列，而SAA1具有Thr-Ile序列。这表明 SAA1 不会以淀粉样 A 蛋白形式沉积，也可能对假定的蛋白水解酶敏感。此外，与小鼠SAA2、人SAA1、猴和水貂淀粉样蛋白A蛋白相比，小鼠SAA1具有两个独特的取代，这可能在淀粉样蛋白组织中小鼠SAA同种型的差异沉积中发挥作用。
cDNA clones encoding two major mouse serum amyloid A proteins, SAA1 and SAA2, were isolated from a liver cDNA library of the lipopolysaccharide-stimulated BALB/c mouse, and their nucleotide sequences were determined. The insert of the SAA2 cDNA clone contained 607 nucleotides with a 5' untranslated region of 36 nucleotides, a signal peptide region corresponding to 19 amino acids, a mature protein region corresponding to 103 amino acids, and a 3' untranslated region of 202 nucleotides. The SAA1 cDNA insert contained 549 nucleotides specifying a part of a signal peptide region, a mature protein region, and a 3' untranslated region. A comparison of the nucleotide and deduced amino acid sequences of SAA1 cDNA with that of SAA2 cDNA showed a high degree of homology: 95% nucleotide sequence homology in the coding region (91% amino acid sequence homology) and 90% homology in the 3' untranslated region. One of nine amino acid differences between SAA1 and SAA2 predicted from the cDNA sequences was located in a putative proteolytic cleavage site for amyloid A protein formation: SAA2 had the Thr-Met sequence in this site, while SAA1 had the Thr-Ile sequence. This suggests that SAA1, which does not deposit as amyloid A protein, is also potentially susceptible to putative proteolytic enzymes. In addition, as compared with mouse SAA2, human SAA1, monkey and mink amyloid A protein, mouse SAA1 had two unique substitutions, which may play a role in differential deposition of mouse SAA isotypes in amyloid tissues.