Architectures of whole-module and bimodular proteins from the 6-deoxyerythronolide B synthase.
Architectures of whole-module and bimodular proteins from the 6-deoxyerythronolide B synthase.
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DOI：
10.1016/j.jmb.2014.03.015
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发表时间：
2014-05-29
影响因子：
5.6
通讯作者：
Khosla C
中科院分区：
文献类型：
--
作者：
Edwards AL;Matsui T;Weiss TM;Khosla C
6-脱氧红霉素B合酶（DEBS）是由放线菌黄多孢菌产生的原型装配线聚酮合酶（PKS），其合成抗生素红霉素6-脱氧红霉素B（6-dEB）的大环核心。大合成酶是一种2 MDa三聚体复合物，由三种独特的同源二聚体组成，这些同源二聚体由基因产物DEBS 1、DEBS 2和DEBS 3组装而成，这些基因产物位于红霉素生物合成基因簇内。每个同二聚体含有两个簇的催化独立的酶结构域，每个称为一个模块，其催化一轮聚酮化合物链延伸和修饰。模块顺序命名，以指示在6-dEB的合成过程中，它们被利用的顺序。我们报告小角X射线散射（SAXS）分析的一个整体模块和双模从DEBS以及一组域的高分辨率结构是可用的。在所有情况下，在先前建立的确保每种蛋白质具有催化活性的条件下探测溶液状态。SAXS数据与DEBS碎片的原子分辨率结构一致。因此，我们使用现有的高分辨率结构的DEBS域建模的架构较大的蛋白质组装体使用刚体细化。我们的数据支持一个模型，其中，第三模块的DEBS形成一个圆盘状的结构能够笼的酰基载体蛋白结构域接近每个活性位点。DEBS 3的分子包络是一个薄的，细长的椭球体，刚体建模的结果表明，模块5和6共线堆叠沿着2重对称轴。
The 6-deoxyerythronolide B synthase (DEBS) is a prototypical assembly line polyketide synthase (PKS) produced by the actinomycete Saccharopolyspora erythraea that synthesizes the macrocyclic core of the antibiotic erythromycin, 6-deoxyerythronolide B (6-dEB). The megasynthase is a 2 MDa trimeric complex comprised of three unique homodimers assembled from the gene products DEBS1, DEBS2, and DEBS3, which are housed within the erythromycin biosynthetic gene cluster. Each homodimer contains two clusters of catalytically independent enzymatic domains, each referred to as a module, which catalyzes one round of polyketide chain extension and modification. Modules are named sequentially to indicate the order in which they are utilized during synthesis of 6-dEB. We report small angle X-ray scattering (SAXS) analyses of a whole module and bimodule from DEBS as well as a set of domains for which high-resolution structures are available. In all cases, the solution state was probed under previously established conditions that ensure each protein is catalytically active. SAXS data are consistent with atomic-resolution structures of DEBS fragments. Therefore, we used the available high-resolution structures of DEBS domains to model the architectures of the larger protein assemblies using rigid body refinement. Our data supports a model in which, the third module of DEBS forms a disc-shaped structure capable of caging the acyl carrier protein domain proximal to each active site. The molecular envelope of DEBS3 is a thin, elongated ellipsoid, and the results of rigid body modeling suggest that modules 5 and 6 stack colinearly along the 2-fold axis of symmetry.
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DOI：
10.1016/j.str.2009.10.018
发表时间：
2010-01-13
期刊：
Structure (London, England : 1993)
影响因子：
--
作者：
Akey DL;Razelun JR;Tehranisa J;Sherman DH;Gerwick WH;Smith JL
通讯作者：
Smith JL
影响因子：
5.6
作者：
KATAOKA, M;HAGIHARA, Y;GOTO, Y
通讯作者：
GOTO, Y
影响因子：
56.9
作者：
Gokhale, RS;Tsuji, SY;Khosla, C
通讯作者：
Khosla, C
影响因子：
--
作者：
Broadhurst, RW;Nietlispach, D;Weissman, KJ
通讯作者：
Weissman, KJ
影响因子：
11
作者：
Doroghazi, James R.;Buckley, Daniel H.
通讯作者：
Buckley, Daniel H.