The elongation factor 1 A-2 isoform from rabbit: Cloning of the cDNA and characterization of the protein
The elongation factor 1 A-2 isoform from rabbit: Cloning of the cDNA and characterization of the protein
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DOI：
10.1093/nar/26.8.1884
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发表时间：
1998-04-15
影响因子：
14.9
通讯作者：
Merrick, WC
中科院分区：
文献类型：
--
作者：
Kahns, S;Lund, A;Merrick, WC
真核细胞伸长因子1 A(eEF1A，前身为伸长因子-1α)是蛋白质合成装置的重要组成部分。本文报道了兔eEF1A-2亚型基因的分离和序列分析，并对两种亚型的结构和功能进行了比较。Northern分析表明，该亚型在骨骼肌、心脏、脑和主动脉中表达，而在肝、肾、脾和肺中未检测到转录本。相反，先前确定的eEF1A-1亚型在除骨骼肌以外的所有组织中都有表达。我们最近从兔骨骼肌中纯化了eEF1A-2。通过部分氨基酸测序和对eEF1A-2翻译后修饰的测定，我们发现eEF1A-1中观察到的两个甘油基磷酰乙醇胺修饰似乎都存在于eEF1A-2中，但在eEF1A-1中发现的两个二甲基化残基似乎在eEF1A-2中三甲基化，酶活性的比较表明eEF1A-1和eEF1A-2在体外翻译系统中具有难以区分的活性。相比之下，eEF1A-1的GDP解离速率常数约为eEF1A-2的7倍，核苷酸偏好比(GDP/GTP)为0.82，而eEF1A-2的偏好比为1.50。
Eukaryotic elongation factor 1 A (eEF1A, formerly elongation factor-1 alpha) is an important component of the protein synthesis apparatus. Here we report the isolation and characterization of the cDNA sequence encoding rabbit eEF1A-2, an isoform of eEF1A, as well as a structural and functional comparison of the two rabbit isoforms, Northern analysis of the expression pattern of eEF1A-2 showed that this isoform is expressed in skeletal muscle, heart, brain and aorta, while transcripts are not detected in liver, kidney, spleen and lung. In contrast, the previously characterized eEF1A-1 isoform is expressed in all tissues examined except skeletal muscle. We have recently purified eEF1A-2 from rabbit skeletal muscle. By partial amino acid sequencing and determination of the posttranslational modifications of eEF1A-2 we found that both of the glycerylphosphorylethanolamine modifications observed in eEF1A-1 appear to be present in eEF1A-2, However, two of the residues found dimethylated in eEF1A-1 appeared to be trimethylated in eEF1A-2, A comparison of the enzymatic activity showed that eEF1A-1 and eEF1A-2 have indistinguishable activity in an in vitro translation system. In contrast, the GDP dissociation rate constant is similar to 7 times higher for eEF1A-1 than for eEF1A-2, The nucleotide preference ratio (GDP/GTP) for eEF1A-1 was 0.82, while the preference ratio for eEF1A-2 was 1.50.