A XENOPUS RIBOSOMAL PROTEIN-S6 KINASE HAS 2 APPARENT KINASE DOMAINS THAT ARE EACH SIMILAR TO DISTINCT PROTEIN-KINASES
A XENOPUS RIBOSOMAL PROTEIN-S6 KINASE HAS 2 APPARENT KINASE DOMAINS THAT ARE EACH SIMILAR TO DISTINCT PROTEIN-KINASES
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DOI：
10.1073/pnas.85.10.3377
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发表时间：
1988-05-01
影响因子：
11.1
通讯作者：
ERIKSON, RL
中科院分区：
文献类型：
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作者：
JONES, SW;ERIKSON, E;ERIKSON, RL
我们报道了非洲爪蟾卵巢组织中S6激酶II (S6KII) mrna的分子克隆。将两个cdna与设计用于编码从S6KII分离的色氨酸的寡核苷酸探针杂交，分离得到。这两个cdna序列相似性为91%。这两个cdna预测733 （s6kii . α .）和629 （s6kii . β .）氨基酸的蛋白质，在它们共线性的629个氨基酸中显示95%的序列相似性。氨基酸44-733的s6kii . α。在大肠杆菌中表达重组蛋白，并用重组蛋白培养家兔抗血清。该抗血清与从爪蟾卵中提取的正宗S6KII反应。这种相互作用被来自大肠杆菌的重组蛋白特别阻断。s6kii . α。和度量。预测四种与从S6KII的胰蛋白酶消化中分离出的四种肽序列相同的胰蛋白酶肽。与先前研究的蛋白激酶相比，S6KII蛋白具有非常不寻常的结构。它们含有两个明显的激酶结构域，每个都类似于不同的蛋白激酶。氨基末端的366个氨基酸与蛋白激酶C （camp依赖性蛋白激酶的催化亚基）和cgmp依赖性蛋白激酶的区域具有高度的序列相似性，这些区域包含ATP结合位点，被认为是磷酸转移酶活性的催化中心。S6激酶分子的剩余部分与atp结合和推定的磷酸化酶b激酶的催化亚基具有高度的序列相似性。
We report the molecular cloning of cDNAs for S6 kinase II (S6KII) mRNAs present in Xenopus ovarian tissue. Two cDNAs were isolated by hybridization to oligonucleotide probes designed to encode tryptic peptides isolated from S6KII. The two cDNAs shows 91% sequence similarity to each other. These two cDNAs predict proteins of 733 (S6KII.alpha.) and 629 (S6KII.beta.) amino acids that show 95% sequence similarity over the 629 amino acids where they are colinear. Amino acids 44-733 of S6KII.alpha. were expressed in Escherichia coli and the recombinant protein was used to raise antiserum in rabbits. This antiserum reacted with authentic S6KII prepared from Xenopus eggs. This interaction was specially blocked by the recombinant protein from E. coli. The sequences of S6KII.alpha. and -.beta. predict four tryptic peptides whose sequences are identical to four peptides isolated from a tryptic digest of S6KII. The S6KII proteins have a very unusual structure when compared with previously studied protein kinases. They contain two apparent kinase domains, each similar to distinct protein kinases. The amino-terminal 366 amino acids show high sequence similarity to the regions of protein kinase C, the catalytic subunit of cAMP-dependent protein kinase, and cGMP-dependent protei kinase that contain the sites for ATP binding and are believed to be the catalytic centers for phosphotransferase activity. Teh remaineder of the S6 kinase molecule shows high sequence similarity to the ATP-binding and presumed catalytic subunit of phosphorylase b kinase.