Zeng Wuwei, Zhang Jian, Chen Baosheng, Wu Gang, Xue Hong
Department of Biochemistry and Molecular Biology, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing 100005, China.
Chin Med J (Engl). 2003 Jun;116(6):928-31.
To obtain the nucleotide sequence and deduced amino acid sequence of cholesteryl ester transfer protein (CETP) cDNA from the tree shrew (Tupaia glis).
The cDNA sequence of the tree shrew CETP was obtained by utilizing the technique of switching mechanism at 5' end of RNA transcript (SMART) and rapid amplification of cDNA end (RACE) from the first strand of the cDNA. The amino acid sequence of CETP was deduced from the cDNA sequence and its primary and secondary structures were predicted.
The sequence of CETP cDNA from tree shrew (GenBank accession number AF334033) covers 1636 bp, including 178 bp at the 3' end of the untranslated region and a 1458 bp fragment in a coding region, which provides the complete sequence of mature tree shrew CETP, although not the initiator methionine. The first 24 bp encodes a partial signal peptide. The mature protein consists of 477 amino acids and is longer than the human version by one amino acid (Gly318). Comparing this amino acid sequence with those of other animals' CETPs, the identity between tree shrew and human and rabbit CETP is 88% and 82%, respectively. The protein is extremely hydrophobic as it contains many hydrophobic residues, especially at the C-terminal, consistent with its function in the transfer of neutral lipids. The amino acid residues concerning with binding and transferring neutral lipids are highly conserved. There is a deletion of an N-linked glycosylation site at Asn342 in the tree shrew CETP protein that may participate in the removal of peripheral cholesterol and cholesteryl ester by increasing its activity of transferring cholesteryl ester.
The possible glycosylation in the tree shrew CETP may be involved in the molecular mechanism of its insusceptibility to atherosclerosis.
获取树鼩（Tupaia glis）胆固醇酯转运蛋白（CETP）cDNA的核苷酸序列及推导的氨基酸序列。
利用RNA转录本5'端切换机制（SMART）技术和cDNA末端快速扩增（RACE）技术，从cDNA第一链中获得树鼩CETP的cDNA序列。从cDNA序列推导CETP的氨基酸序列，并预测其一级和二级结构。
树鼩CETP cDNA序列（GenBank登录号AF334033）全长1636 bp，包括3'端非翻译区178 bp和编码区1458 bp片段，该片段提供了成熟树鼩CETP的完整序列，但不包括起始甲硫氨酸。前24 bp编码部分信号肽。成熟蛋白由477个氨基酸组成，比人类版本长一个氨基酸（Gly318）。将该氨基酸序列与其他动物的CETP序列进行比较，树鼩与人类和兔CETP的同一性分别为88%和82%。该蛋白具有极强的疏水性，因为它含有许多疏水残基，尤其是在C末端，这与其在中性脂质转运中的功能一致。与结合和转运中性脂质有关的氨基酸残基高度保守。树鼩CETP蛋白在Asn342处缺失一个N-连接糖基化位点，该位点可能通过增加其胆固醇酯转运活性参与外周胆固醇和胆固醇酯的清除。
树鼩CETP中可能的糖基化作用可能参与了其对动脉粥样硬化不敏感的分子机制。
