Crystallization, structure determination and least-squares refinement to 1.75 A resolution of the fatty-acid-binding protein isolated from Manduca sexta L.
Crystallization, structure determination and least-squares refinement to 1.75 A resolution of the fatty-acid-binding protein isolated from Manduca sexta L.
复制标题
从 Manduca sexta L 中分离的脂肪酸结合蛋白的结晶、结构测定和最小二乘精修至 1.75 A 分辨率。
DOI：
10.1016/0022-2836(92)90501-a
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发表时间：
1992
影响因子：
5.6
通讯作者：
Holden,HM
中科院分区：
文献类型：
--
作者：
Benning,MM;Smith,AF;Wells,MA;Holden,HM
烟草天蛾脂肪酸结合蛋白的分子结构分析已被确定并细化到1.75 A的标称分辨率。研究中所用的晶体是从用50 ml琥珀酸钠缓冲的pH 4.5的1.6 M硫酸铵溶液中生长的，属于空间群P2，晶胞尺寸为a= 27-5 A，B= 71.0 A，c= 28.7 A和B= 90.8”。一个电子密度图，与四个重原子衍生物相，并计算到2.5 A的分辨率，允许131个氨基酸残基的多肽链的完整跟踪。随后对模型进行最小二乘改进，使用从30.0 A到1.75 A的所有测量X射线数据将R因子从46.09/“降低到17.3 O/”。大约92“/B的氨基酸残基属于经典的二级结构元件，包括十条反平行b-折叠片、两个a-螺旋、一个I型转角、三个II型转角、四个II'型转角和一个III型转角。与其他脂肪酸结合蛋白一样，昆虫分子的整体分子结构由十条反平行的B折叠片组成，形成两层几乎相互正交的层。螺旋-转角-螺旋基序位于蛋白质的N-末端部分，位于上下/？-每桶脂肪酸的官能团在Gln 39、Tyr 129、Arg 127和硫酸酯分子的氢键距离内，而配体的脂肪族部分被衬在B-桶上的疏水性氨基酸残基包围。配体的羧酸部分的结合与在P2髓磷脂蛋白和鼠脂肪细胞脂质结合蛋白中观察到的非常相似，但是烃尾在大约β 16之后的定位完全不同。
The molecular structure of an insect fatty-acid-binding protein isolated from Manduca sexta L. has been determined and refined to a nominal resolution of 1.75 A. Crystals used in the investigation were grown from 1.6 M-ammonium sulfate solutions buffered at pH 4.5 with 50 mlvr-sodium succinate, and belonged to space group P2, with unit cell dimensions of a= 27-5 A, b= 71.0 A, c= 28.7 A and B= 90.8”. An electron density map, phased with four heavy-atom derivatives and calculated to 2.5 A resolution, allowed for complete tracing of the 131 amino acid residue polypeptide chain. Subsequent least-squares refinement of the model reduced the R-factor from 46.09/, to 17.3 O/” using all measured X-ray data from 30.0 A to 1.75 A. Approximately 92 “/b of the amino acid residues fall into classical secondary structural elements including ten strands of anti-parallel b-pleated sheet, two a-helices, one type I turn, three type II turns, four type II’turns and one type III turn. As in other fattyacid-binding proteins, the overall molecular architecture of the insect molecule consists of ten strands of anti-parallel B-pleated sheet forming two layers that are nearly orthogonal to one another. A helix-turn-helix motif at the N-terminal portion of the protein flanks one side of the up-and-down/?-barrel. The functional group of the fatt, y acid is within hydrogenbonding distance of Gln39, Tyr129, Arg127 and a sulfate molecule, while the aliphatic portion of the ligand is surrounded by hydrophobic amino acid residues lining the B-barrel. The binding of the carboxylic acid portion of t’he ligand is very similar t’o that observed in P2 myelin protein and the murine adipocyte lipid-binding protein, but the positioning of the hydrocarbon tail after approximately(16 is completely different.