Disruption of the C-terminal helix by single amino acid deletion is directly responsible for impaired cholesterol efflux ability of apolipoprotein A-I Nichinan
Disruption of the C-terminal helix by single amino acid deletion is directly responsible for impaired cholesterol efflux ability of apolipoprotein A-I Nichinan
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DOI：
10.1194/jlr.m002113
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发表时间：
2010-04-01
影响因子：
6.5
通讯作者：
Saito, Hiroyuki
中科院分区：
文献类型：
--
作者：
Kono, Momoe;Tanaka, Toshitaka;Saito, Hiroyuki
载脂蛋白 A-I (apoA-I) Nichinan 是一种天然存在的变体，C 末端有 Delta E235，与低血浆 HDL 水平相关。在这里，我们研究了 apoA-I Nichinan 及其 C 末端肽的三级结构、脂质结合特性以及诱导细胞胆固醇流出的能力。热变性和化学变性实验表明，与野生型（WT）相比，Delta E235 突变降低了蛋白质稳定性。 ApoA-I Nichinan 表现出结合或溶解脂质囊泡的能力，该能力介于 WT 和 L230P/L233P/Y236P 变体的中间，其中 C 端 α 螺旋折叠完全破坏并形成相对较大且不稳定的盘状复合物，表明 Delta 对 C 端 α 螺旋结构的扰动 E235 突变导致脂质结合减少。支持这一点的是，apoA-I 209241/Delta E235 肽在无脂质和脂质结合状态下均表现出显着降低的形成 α 螺旋的能力，并且溶解囊泡的效率降低。此外，apoA-I Nichinan 及其 C 末端肽在 ABCA1 介导的细胞胆固醇流出中表现出活性降低。因此，E235 缺失引起的 C 端区域形成 α 螺旋能力的破坏似乎是脂质结合和胆固醇流出能力受损的重要决定因素，因此，apoA-I Nichinan 先证者的血浆 HDL 水平较低。-Kono, M., T. Tanaka, M. Tanaka, C. Vedhachalam, P. S. Chetty、D. Nguyen、P. Dhanasekaran、S. Lund-Katz、M. C. Phillips 和 H. Saito。单个氨基酸缺失对 C 末端螺旋的破坏是载脂蛋白 A-I Nichinan 胆固醇流出能力受损的直接原因。 J.脂质研究。 2010。51：809-818。
Apolipoprotein A-I (apoA-I) Nichinan, a naturally occurring variant with Delta E235 in the C terminus, is associated with low plasma HDL levels. Here, we investigated the tertiary structure, lipid-binding properties, and ability to induce cellular cholesterol efflux of apoA-I Nichinan and its C-terminal peptide. Thermal and chemical denaturation experiments demonstrated that the Delta E235 mutation decreased the protein stability compared with wild type (WT). ApoA-I Nichinan exhibited capabilities to bind to or solubilize lipid vesicles that are intermediate to that of WT and a L230P/L233P/Y236P variant in which the C-terminal alpha-helix folding is completely disrupted and forms relatively larger and unstable discoidal complexes, indicating that perturbation of the C-terminal alpha-helical structure by the Delta E235 mutation leads to reduced lipid binding. Supporting this, apoA-I 209241/Delta E235 peptide showed significantly decreased ability to form alpha-helix both in the lipid-free and lipid-bound states, and reduced efficiency to solubilize vesicles. In addition, both apoA-I Nichinan and its C-terminal peptide exhibited reduced activity in ABCA1-mediated cellular cholesterol efflux. Thus, the disruption of the ability of the C-terminal region to form alpha-helix caused by the E235 deletion appears to be the important determinant of impaired lipid binding and cholesterol efflux ability and, consequently, the low plasma HDL levels of apoA-I Nichinan probands.-Kono, M., T. Tanaka, M. Tanaka, C. Vedhachalam, P. S. Chetty, D. Nguyen, P. Dhanasekaran, S. Lund-Katz, M. C. Phillips, and H. Saito. Disruption of the C-terminal helix by single amino acid deletion is directly responsible for impaired cholesterol efflux ability of apolipoprotein A-I Nichinan. J. Lipid Res. 2010. 51: 809-818.