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电压依赖性钙离子通道(voltage-dependent calcium channels,VDCC)是细胞膜上控制Ca2+进入胞内的特殊蛋白质,VDCCβ亚基具有调节其通道活性的作用.使用RT-PCR和RACE PCR技术,从海刺参(Stichopus japonicus)肠中克隆得到电压依赖性钙离子通道β亚基(SjCaβ)基因,所得序列提交GenBank,登录号EU853658.该基因全长1 867 bp,包含1个1 614 bp的开放阅读框(ORF),编码537个氨基酸.将SjCaβ与多种无脊椎动物钙离子通道β亚基进行分析比较,发现它们有较高的同源性,并具有钙离子通道β亚基基因内保守的2个功能区域,即SH3功能区(src-homology 3 domain)和GK功能区(guanylate kinase domain).在功能区域附近还具有电压依赖性钙离子通道β亚基特有的BID区(βinteraction domain),氨基酸保守序列为PYDVVP-RP---VGPSLKGYEVTDMMQKALFDF,进一步确定了得到的cDNA序列为海刺参电压依赖性钙离子通道β亚基.对SjCaβ的二级结构进行了预测,构建了系统进化发育树,并运用同源建模法构建了SjCaβ的三维结构模型.研究结果对深入研究海刺参离子通道的结构以及在信号传导过程中的作用有着重要意义,并为研究海刺参自溶等问题提供一定的理论基础.
Voltage-dependent calcium channels (VDCCs) are special proteins that regulate the entry of Ca2 + into the cell membrane, and VDCCβ subunits play a role in regulating their channel activity.Using RT-PCR and RACE PCR techniques, (Stjopus japonicus) was cloned to obtain a voltage-dependent calcium channel β subunit (SjCaβ) gene, the resulting sequence submitted to GenBank accession number EU853658. The full-length gene of 1 867 bp, contains a 1 614 bp open reading frame (ORF), which encodes 537 amino acids.Comparing SjCaβ with the β subunits of calcium channels in a variety of invertebrates, we found that they have high homology and have conserved 2 Function domains, ie, the src-homology 3 domain and the guanylate kinase domain, a Binteraction domain specific to the beta subunit of the voltage-dependent calcium channel in the vicinity of the functional domain, The conserved sequence was PYDVVP-RP --- VGPSLKGYEVTDMMQKALFDF, and the cDNA sequence of sea cucumber Apostichopus japonicus was determined to be the voltage-dependent Ca 2+ channel β subunit of S. japonicus. The secondary structure of SjCaβ was predicted, The phylogenetic tree was constructed and the three-dimensional structural model of SjCaβ was constructed by using the homology modeling method.These results are of great importance to further study the structure of the ion channel of sea cucumber and its role in signal transduction, Autolysis and other issues to provide a certain theoretical basis.