The integrity of the α-helical domain of intestinal fatty acid binding protein is essential for the collision-mediated transfer of fatty acids to phospholipid membranes
The integrity of the α-helical domain of intestinal fatty acid binding protein is essential for the collision-mediated transfer of fatty acids to phospholipid membranes
复制标题
DOI：
10.1016/j.bbalip.2008.01.005
复制
发表时间：
2008-04-01
影响因子：
4.8
通讯作者：
Corsico, B.
中科院分区：
文献类型：
--
作者：
Franchini, G. R.;Storch, J.;Corsico, B.
肠 FABP (IFABP) 和肝 FABP (LFABP) 是在肠吸收细胞中高水平表达的同源蛋白，采用明显不同的脂肪酸转移至受体模型膜的机制。 IFABP 的转移发生在蛋白质-膜碰撞相互作用期间，而 LFABP 的转移则通过水相扩散发生。此外，从 IFABP 的传输速度明显快于从 LFABP 的传输速度。本研究的总体目标是进一步探讨 IFABP 和 LFABP 之间的结构差异，这些差异是它们在配体转运方面的巨大功能差异的基础。特别是，我们探讨了 α I-螺旋结构域在肠道 FABP 独特转运特性中的作用。利用 IFABP 的“主体”（配体结合结构域）和 LFABP 的 α I 螺旋（α(I) L beta IFABP）设计了嵌合蛋白，并使用荧光共振能量转移测定法检查了嵌合 FABP 的脂肪酸转移特性。结果显示，与 IFABP 相比，α(I)L beta IFABP 的 FA 转移绝对率显着降低。结果表明，α I 螺旋对于 IFABP 碰撞 FA 转移至关重要，并进一步表明全螺旋参与蛋白质膜“碰撞复合物”的形成。使用光活化试剂进行的光交联实验证明了 IFABP 与膜的直接相互作用，并进一步支持了 IFABP 的 α I 螺旋在其与膜的物理相互作用中的重要性。 (C) 2008 Elsevier B.V. 保留所有权利。
Intestinal FABP (IFABP) and liver FABP (LFABP), homologous proteins expressed at high levels in intestinal absorptive cells, employ markedly different mechanisms of fatty acid transfer to acceptor model membranes. Transfer from IFABP occurs during protein-membrane collisional interactions, while for LFABP transfer occurs by diffusion through the aqueous phase. In addition, transfer from IFABP is markedly faster than from LFABP. The overall goal of this study was to further explore the structural differences between IFABP and LFABP which underlie their large functional differences in ligand transport. In particular, we addressed the role of the alpha I-helix domain in the unique transport properties of intestinal FABP. A chimeric protein was engineered with the 'body' (ligand binding domain) of IFABP and the alpha I-helix of LFABP (alpha(I) L beta IFABP), and the fatty acid transfer properties of the chimeric FABP were examined using a fluorescence resonance energy transfer assay. The results showed a significant decrease in the absolute rate of FA transfer from alpha(I)L beta IFABP compared to IFABP. The results indicate that the alpha I-helix is crucial for IFABP collisional FA transfer, and further indicate the participation of the all-helix in the formation of a protein-membrane "collisional complex". Photo-crosslinking experiments with a photoactivable reagent demonstrated the direct interaction of IFABP with membranes and further support the importance of the alpha I helix of IFABP in its physical interaction with membranes. (C) 2008 Elsevier B.V. All rights reserved.