Liu Zhi-Guo, Qu Shen, Feng Ning, Zong Yi-Qiang, Deng Yao-Zu, Feng Zong-Chen
Department of Biochemistry & Molecular Biology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
Sheng Wu Hua Xue Yu Sheng Wu Wu Li Xue Bao (Shanghai). 2002 Mar;34(2):158-64.
The ligand-binding domain of the very low-density lipoprotein receptor (VLDL-R) contains eight cysteine-rich repeat sequences that have been postulated as ligand-binding sites. This is obviously different from that of low-density lipoprotein receptor (LDL-R) that includes seven similar repeats. To make clear the contribution of these repeats to ligand-binding and to explore the reason of both receptors' ligand-binding characteristic, the VLDL-R recombinants lacking different repeat(s) were constructed by oligonucleotide-directed mutagenesis and transfected into ldl-A7 cell. Ligand-binding results showed that repeat 1 and repeat 2 were the most important in binding with apoE-rich lipoprotein(VLDL and beta-VLDL). Repeat 3 and repeat 6 also important for binding VLDL. The results also showed that VLDL-R lacking LBR7 retained partly LDL-R ligand-binding properties. It suggests that LBR7 in VLDL-R may responsible for both receptors' ligand-binding properties differences.
极低密度脂蛋白受体（VLDL-R）的配体结合结构域包含八个富含半胱氨酸的重复序列，这些序列被认为是配体结合位点。这显然与低密度脂蛋白受体（LDL-R）不同，后者包括七个相似的重复序列。为了明确这些重复序列对配体结合的贡献，并探究两种受体配体结合特性的原因，通过寡核苷酸定向诱变构建了缺失不同重复序列的VLDL-R重组体，并将其转染到ldl-A7细胞中。配体结合结果表明，重复序列1和重复序列2在与富含载脂蛋白E的脂蛋白（VLDL和β-VLDL）结合中最为重要。重复序列3和重复序列6对结合VLDL也很重要。结果还表明，缺乏LBR7的VLDL-R保留了部分LDL-R配体结合特性。这表明VLDL-R中的LBR7可能是两种受体配体结合特性差异的原因。
