Structure of the human-heart fatty-acid-binding protein 3 in complex with the fluorescent probe 1-anilinonaphthalene-8-sulphonic acid.
Structure of the human-heart fatty-acid-binding protein 3 in complex with the fluorescent probe 1-anilinonaphthalene-8-sulphonic acid.
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DOI：
10.1107/s0909049513021298
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发表时间：
2013-11
影响因子：
2.5
通讯作者：
Murata M
中科院分区：
文献类型：
--
作者：
Hirose M;Sugiyama S;Ishida H;Niiyama M;Matsuoka D;Hara T;Mizohata E;Murakami S;Inoue T;Matsuoka S;Murata M
在2.15 nm处解析了人心脏型脂肪酸结合蛋白与苯胺基萘-8-磺酸盐复合物的晶体结构，揭示了荧光探针1-苯胺基萘-8-磺酸盐的详细结合机理。 心脏型脂肪酸结合蛋白（Heart-type fatty-acid-binding protein，FABP 3）是一种在心肌细胞中大量存在的胞质蛋白，通过以相对高的亲和力可逆结合细胞内脂肪酸，在整个细胞区室中运输脂肪酸中发挥作用。荧光探针1-苯胺基萘-8-磺酸盐（ANS）被广泛用于检测配体与脂肪酸结合蛋白的相互作用。在ANS存在下测定了FABP 3的X射线结构，并揭示了详细的ANS结合机制。此外，在结合腔中清楚地识别出四个水分子。通过这些水分子，结合的ANS分子与FABP 3形成间接的氢键相互作用。脂肪细胞型脂肪酸结合蛋白（FABP 4）与FABP 3具有67%的序列同一性，其晶体结构与FABP 3几乎相同。然而，FABP 4可以以比FABP 3更高的亲和力与ANS结合。为了理解它们的配体特异性的差异，在FABP 3-ANS和FABP 4-ANS复合物之间进行结构比较。结果表明，ANS与FABP 3和FABP 4的结合方向完全相反，FABP 4中的缬氨酸被FABP 3中的亮氨酸取代可能导致Leu 115侧链与ANS苯胺环之间的空间位阻增大。
The crystal structure of human-heart-type fatty-acid-binding protein in complex with anilinonaphthalene-8-sulfonate was solved at 2.15 Å resolution revealing the detailed binding mechanism of the fluorescent probe 1-anilinonaphthalene-8-sulfonate. Heart-type fatty-acid-binding protein (FABP3), which is a cytosolic protein abundantly found in cardiomyocytes, plays a role in trafficking fatty acids throughout cellular compartments by reversibly binding intracellular fatty acids with relatively high affinity. The fluorescent probe 1-anilinonaphthalene-8-sulfonate (ANS) is extensively utilized for examining the interaction of ligands with fatty-acid-binding proteins. The X-ray structure of FABP3 was determined in the presence of ANS and revealed the detailed ANS-binding mechanism. Furthermore, four water molecules were clearly identified in the binding cavity. Through these water molecules, the bound ANS molecule forms indirect hydrogen-bond interactions with FABP3. The adipocyte-type fatty-acid-binding protein (FABP4) exhibits 67% sequence identity with FABP3 and its crystal structure is almost the same as that of FABP3. However, FABP4 can bind with a higher affinity to ANS than FABP3. To understand the difference in their ligand specificities, a structural comparison was performed between FABP3–ANS and FABP4–ANS complexes. The result revealed that the orientation of ANS binding to FABP3 is completely opposite to that of ANS binding to FABP4, and the substitution of valine in FABP4 to leucine in FABP3 may result in greater steric hindrance between the side-chain of Leu115 and the aniline ring of ANS.