Solution structure and dynamics of oxytetracycline polyketide synthase acyl carrier protein from Streptomyces rimosus
Solution structure and dynamics of oxytetracycline polyketide synthase acyl carrier protein from Streptomyces rimosus
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DOI：
10.1021/bi0342259
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发表时间：
2003-07-22
期刊：
影响因子：
2.9
通讯作者：
Crump, MP
中科院分区：
文献类型：
--
作者：
Findlow, SC;Winsor, C;Crump, MP
II型聚酮酶（PKS）在特定聚酮产物的生物合成中利用专用的和必需的酰基载体蛋白（ACP）。作为我们正在进行的研究的机制和控制聚酮生物合成的一部分，我们报告的聚酮合酶ACP的第二个结构。在这项工作中，多维，异相NMR研究的结构和动力学的ACP参与的生物合成的常用处方的聚酮抗生素，土霉素（otc）。用模拟退火法计算了95个氨基酸的28个结构的otc ACP（9916 Da），其中包括1132个实验约束。所有28个模型的平均结构的原子RMSD对于骨架原子为0.66埃，对于所有重原子为1.15埃（两个值都是针对蛋白质的折叠部分（残基3-80）计算的），并且对于二级结构内的骨架原子为0.41埃。Otc ACP采用目前已知ACP的典型右手四螺旋折叠，但添加了13个残基的柔性C-末端。所有结构特征的ACP的全球折叠的比较进行了描述，说明PKS ACP显示出明显的差异，以及FAS ACP的相似之处。N-15弛豫实验的蛋白质骨架也表明，螺旋I和II之间的长环是灵活的和螺旋II，蛋白质-蛋白质相互作用的建议网站，显示构象交换。ACP的螺旋形成蛋白质的刚性支架，但这些支架中散布着不寻常比例的柔性接头区域。
Type II polyketide synthases (PKSs) utilize a dedicated and essential acyl carrier protein (ACP) in the biosynthesis of a specific polyketide product. As part of our ongoing studies into the mechanisms and control of polyketide biosynthesis, we report the second structure of a polyketide synthase ACP. In this work, multidimensional, heteronuclear NMR was employed to investigate the structure and dynamics of the ACP involved in the biosynthesis of the commonly prescribed polyketide antibiotic, oxytetracycline (otc). An ensemble of 28 structures of the 95 amino acid otc ACP (9916Da) was computed by simulated annealing with the inclusion of 1132 experimental restraints. Atomic RMSDs about the mean structure for all 28 models is 0.66 Angstrom for backbone atoms, 1.15 Angstrom for all heavy atoms (both values calculated for the folded part of the protein (residues 3-80)), and 0.41 Angstrom for backbone atoms within secondary structure. Otc ACP adopts the typical right-handed, four-helix fold of currently known ACPs but with the addition of a 13-residue flexible C-terminus. A comparison of the global folds of all structurally characterized ACPs is described, illustrating that PKS ACPs show clear differences as well as similarities to FAS ACPs. N-15 relaxation experiments for the protein backbone also reveal that the long loop between helices I and II is flexible and helix II, a proposed site of protein-protein interactions, shows conformational exchange. The helices of the ACP form a rigid scaffold for the protein, but these are interspersed with an unusual proportion of flexible linker regions.