摘要
为获得不易感动脉粥样硬化动物北京鸭卵磷脂胆固醇酰基转移酶 (LCAT)的cDNA和蛋白质序列 ,分析其结构特点 .以从北京鸭肝脏mRNA反转录获得的cDNA一链为模板 ,应用SMART RACE技术 ,获得了北京鸭LCAT的cDNA序列 ,推导出其蛋白质氨基酸序列 ,应用分子生物学软件对该蛋白的一级、二级结构进行分析和比较 .北京鸭LCATcDNA (在GenBank中的注册号为AF32 4 887)全长 195 3bp ,其中开放阅读框架 135 6bp ,编码 4 5 1个氨基酸 ,包括一个由 2 3个氨基酸构成的疏水性信号肽和一个由 4 2 8个氨基酸组成的成熟蛋白 .该成熟蛋白比人LCAT在C端多 12个氨基酸 ,其与鸡、人、家兔的同源性依次为 98%、83%和 82 % .与其它种属LCAT蛋白序列的比较结果表明 ,北京鸭LCAT蛋白质序列虽然在长度上和结构上与其它种属有一定的差异 。
To obtain the nucleotide sequence and deduced amino acid sequence of lecithin∶cholesterol acyltransferase (LCAT) cDNA from Beijing Duck, one kind of anti atherosclerosis animals. The sequence of lecithin:cholesterol acyltransferase cDNA from Beijing Duck was obtained by utilizing the technique of SMART(Switching Mechanism At 5′ end of RNA Transcript) and RACE(Rapid Amplification of cDNA End) from the first strand of cDNA. The amino acid sequence of Beijing Duck LCAT was deduced from this cDNA and its primary and secondary structures were predicted by using softwares for molecular biology. The cDNA sequence of lecithin∶cholesterol acyltransferase from Beijing Duck covered 1 953 bp, including a 1 356 bp fragment in an open reading frame(ORF) as well as 1bp and 596 bp at 5′ and 3′ of the untranslated regions respectively. The ORF encoded 451 amino acids(aa) precuser, which contained a hydrophobic signal peptide of 23 amino acids and a mature peptide of 428 amino acids. Comparing and aligning this amino acid sequence of LCAT with those of other published animals, it revealed that the mature protein had more 12 amino acids than that of the human, baboon and rabbit. The homology among Beijing Duck and chicken, human, rabbit LCAT were 98%, 83% and 82% at protein level,respectively. The amino acid residues concerned with the catalytic activity were highly conserved. The cDNA sequence of LCAT from Beijing Duck was registered at GenBank with the accession number of AF324887. Although the amino acid sequence of Beijing Duck LCAT has some difference from that of other species, the regions which are important to function of LCAT are highly preserved.
出处
《中国生物化学与分子生物学报》
CAS
CSCD
北大核心
2002年第1期64-69,共6页
Chinese Journal of Biochemistry and Molecular Biology
基金
国家攀登计划资助项目
国家自然科学基金资助课题 (No.39770 16 8)
